STUDY PROTOCOL Open Access

Baby-Led Introduction to SolidS (BLISS)study: a randomised controlled trial of ababy-led approach to complementaryfeedingLisa Daniels1,2, Anne-Louise M. Heath1*, Sheila M. Williams3, Sonya L. Cameron4, Elizabeth A. Fleming1,Barry J. Taylor4,5, Ben J. Wheeler4,5, Rosalind S. Gibson1 and Rachael W. Taylor2,5

Abstract

Background: In 2002, the World Health Organization recommended that the age for starting complementaryfeeding should be changed from 4 to 6 months of age to 6 months. Although this change in age has generatedsubstantial debate, surprisingly little attention has been paid to whether advice on how to introduce complementaryfoods should also be changed. It has been proposed that by 6 months of age most infants will have developedsufficient motor skills to be able to feed themselves rather than needing to be spoon-fed by an adult. This has thepotential to predispose infants to better growth by fostering better energy self-regulation, however no randomisedcontrolled trials have been conducted to determine the benefits and risks of such a “baby-led” approach tocomplementary feeding. This is of particular interest given the widespread use of “Baby-Led Weaning” by parentsinternationally.

Methods/Design: The Baby-Led Introduction to SolidS (BLISS) study aims to assess the efficacy and acceptability of amodified version of Baby-Led Weaning that has been altered to address potential concerns with iron status, chokingand growth faltering. The BLISS study will recruit 200 families from Dunedin, New Zealand, who book into the region’sonly maternity hospital. Parents will be randomised into an intervention (BLISS) or control group for a 12-monthintervention with further follow-up at 24 months of age. Both groups will receive the standard Well Child careprovided to all parents in New Zealand. The intervention group will receive additional parent contacts (n = 8) forsupport and education on BLISS from before birth to 12 months of age. Outcomes of interest include body mass indexat 12 months of age (primary outcome), energy self-regulation, iron and zinc intake and status, diet quality, choking,growth faltering and acceptability to parents.

Discussion: This study is expected to provide insight into the feasibility of a baby-led approach to complementaryfeeding and the extent to which this method of feeding affects infant body weight, diet quality and iron and zincstatus. Results of this study will provide important information for health care professionals, parents and health policymakers.

Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12612001133820.

Keywords: Baby-Led Weaning, Complementary feeding, Energy self-regulation, Childhood obesity, Iron deficiency

* Correspondence: anne-louise.heath@otago.ac.nz1Department of Human Nutrition, University of Otago, PO Box 56, Dunedin9054, New ZealandFull list of author information is available at the end of the article

© 2015 Daniels et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Daniels et al. BMC Pediatrics (2015) 15:179 DOI 10.1186/s12887-015-0491-8

BackgroundIn 2002, the World Health Organization (WHO) recom-mended that the age when complementary feeding, orthe introduction of “solid” foods, should start should bechanged from 4 to 6 months to 6 months of age [1, 2].This change was a consequence of the WHO recom-mending an extension to the exclusive breastfeedingphase from 4 to 6 months to 6 months (180 days) of age[3]. By 6 months of age, the infant’s renal function, di-gestive function and oral motor skills (i.e. chewing andswallowing) have developed enough to manage solidfoods [4]. Furthermore, by this age complementary feed-ing is needed to ‘complement’ the nutrients and energyprovided by breast milk to ensure appropriate growthand development [3]. Although there has been consider-able debate about this change in the age when comple-mentary feeding should be initiated [5–7], there hasbeen surprisingly little attention paid to whether adviceon how to introduce complementary foods should alsobe changed given the substantial development in gross,fine and oral motor skills that occurs between 4 and6 months of age.Traditionally, complementary feeding has been based

on graduated exposure to solid foods with different tex-tures [8–10]. This means that infants are given puréedfoods before progressing to mashed and chopped foods,with ‘finger’ foods not contributing a large part of thediet until later in the complementary feeding period(typically around 8–9 months of age). As outlined inTable 1, this advice has changed little in response to thechange in the recommended age for introducing com-plementary foods, despite marked changes in physicaldevelopment between 4 and 6 months of age. Puréedfoods may have been necessary at 4 months because in-fants have a limited ability to chew at this age and mostare not able to sit unsupported [11]. However, by 6–7 months of age most infants are able to chew, sit un-supported and bring foods to their mouth [11], suggest-ing that a gradual transition from purées to finger foods

may now not be necessary [12]. If this is indeed the case,then both the types of foods offered, and the role of par-ents in infant feeding, may be altered and this may haveimportant implications for infant health outcomes in-cluding obesity, nutritional status and choking risk.

Baby-Led WeaningBaby-Led Weaning (BLW) differs from the traditionalapproach to complementary feeding because the infantis encouraged to feed themselves all their foods fromthe beginning of the complementary feeding period [12].While most countries recommend that finger foods areincluded in the complementary feeding period, evenfrom as early as 6 months of age in the United Kingdom(UK) [8, 10, 13, 14], they generally only represent a smallcomponent of the complementary feeding diet, particu-larly in the first few months. In contrast, parents follow-ing BLW choose a range of foods to offer their infantand the infant decides which of the foods to eat, howmuch and at what pace they will eat them [12]. The keyfeatures of BLW are [12, 15]:

� Milk feeding – the infant will ideally be exclusivelybreastfed until 6 months of age, although it isacknowledged that some infants will be formula fed.When complementary feeding starts (once theinfant is ready, at around 6 months of age) theinfant continues to receive milk feeds (breast milk orinfant formula) on demand.

� Baby-led – the infant self-feeds from the beginningof the complementary feeding period. Generallyspeaking puréed foods are not eaten because theyneed to be spoon-fed and therefore fed by someoneother than the infant. Some families may offer thechild utensils so that they can feed themselves pu-rées or foods with a thin consistency (e.g., yoghurtand custard) but this is unlikely in the first fewmonths for developmental reasons.

� Family foods – the infant is offered the same foodsas the family but as finger food that is large enoughfor them to pick up. These pieces can get smallerwith increasing developmental age.

� Mealtimes – the family eats together at mealtimes.

Although BLW has received considerable attention inboth the scientific literature [11, 12, 16–22] and the laymedia, the New Zealand Ministry of Health does notcurrently recommend BLW as an alternative to currentcomplementary feeding advice because of the paucity ofresearch on the topic [23]. Although agencies such asthe United Kingdom Department of Health [13] andHealth Canada [14] suggest that finger foods can be of-fered as part of the diet from the beginning of comple-mentary feeding at 6 months of age, they do not

Table 1 Appropriate textures for complementary feedingaccording to current recommendations in New Zealand [8],United States of America [9], and Australia [10]

Approximate age Appropriate texture

0 – 6 months Liquid

6 – 7 months Puréed

7 – 8 months Mashed and “Finger”a foods

8 – 12 months Chopped

12 – 24 months “Family”b foodsa Finger foods are foods that can be picked up by the child and eaten “withthe fingers”b Family foods are foods that are eaten by the rest of the family, in the formthat they are eaten by the rest of the family

Daniels et al. BMC Pediatrics (2015) 15:179 Page 2 of 15

recommend a baby-led approach in which the entire dietis self-fed.

Potential advantages of Baby-Led WeaningA number of potential advantages of BLW have been pro-posed, including: a lower risk of obesity, as a result of bet-ter energy self-regulation; better diet quality; favourableeffects on parental feeding practices; and more highly de-veloped motor skills [24].

Lower risk of obesityOne potential advantage proposed by advocates of Baby-Led Weaning is that it may encourage improved energyself-regulation [12], defined as “the capacity to adjust thequantity eaten according to the physiological needs ofthe consumer” [25]. In turn, this is expected to lowerthe risk of obesity. Advocates propose that the milk-onlydiet that infants consume from birth allows them to bein control of when and how much they consume, par-ticularly if they are breastfed on demand. However, whencomplementary foods are introduced using the trad-itional spoon feeding approach, the parent has muchmore control and is likely to encourage the child to eatuntil they have consumed an amount of food that theparent, rather than the child, considers is “enough” [24].By contrast, BLW encourages the infant to be in controlof the amount eaten and it is suggested that this maysupport the responsiveness to internal hunger and sati-ety cues, leading to better energy self-regulation [16, 23,26]. There is increasing evidence that better energy self-regulation is associated with a lower risk of obesity [27].To date, only two studies have investigated rates of

obesity in infants following BLW [17, 21]. Brown andLee [21] found no association between the complemen-tary feeding method (BLW or spoon feeding) and paren-tally reported infant weight at 6 months in a large (n =652) cross-sectional study. However, when they mea-sured a subset (n = 298 participants at 18–24 months ofage who consented to follow-up contact and met inclu-sion criteria) they found that toddlers who had followedBLW as infants had significantly lower mean bodyweight (by 1.07 kg), than those who had followed a trad-itional ‘parent-led’ spoon feeding approach [28]. More-over, the infants who had followed BLW were reportedby their parent to be significantly more satiety-responsive (able to regulate intake of food in relation tosatiety) and significantly less food-responsive (eating inresponse to food stimuli regardless of hunger), than theirtraditionally fed peers [28]. Similarly, Townsend andPitchford [17] reported significantly lower Body MassIndex (BMI) and incidence of obesity in children at 20–78 months who had followed BLW compared to thosewho had been spoon-fed. However, different methodswere used to recruit the BLW and spoon-fed participants

and standardized procedures for measuring body weightwere only used in the spoon-fed group, making these re-sults difficult to interpret.These initial studies are intriguing and suggest that a

baby-led method of complementary feeding may help toaddress the growing obesity problem worldwide [23].However, it is not possible to conclude from thesecross-sectional studies that BLW itself was responsiblefor differences in body weight, or energy self-regulation, particularly because parents who followBLW have been shown to differ from parents follow-ing traditional methods of complementary feeding indemographic, psychological and parenting characteris-tics known to also be associated with body weight[19, 21]. Only a randomised controlled trial can con-firm whether a beneficial relationship exists betweeninfant self-feeding and body weight.

Better diet qualityWhile it is often assumed that infants following BLWwill consume diets of better quality, there are very lim-ited dietary data from infants following BLW. Rowanand Harris [22] used three day diet records to assessfoods eaten by parents whose infants were followingBLW, in order to determine whether BLW influencedthe parents’ food intake. Although the authors reportedthat a wide range of foods were offered to the infants,the infants’ actual nutrient intake was not determined.Furthermore, the study was a pilot study so was verysmall (n = 10 participants).It is possible that BLW may promote acceptance of a

wider range of foods as a result of early exposure to arange of different tastes and textures from a variety offoods [15], but this has not yet been formally investi-gated. One cross-sectional study found that infants whowere mostly being fed using the BLW method weremore likely to be consuming family foods (p = 0.018),were more likely to begin this at the start of comple-mentary feeding (p <0.001) and were less likely to begiven commercial infant foods (p = 0.002), comparedwith infants whose parents were following a more trad-itional ‘parent-led’ spoon feeding approach [19]. Familyfoods would be expected to be more varied in taste andtexture than the foods offered at the start of comple-mentary feeding (predominantly puréed fruit, vegetablesor cereal). However, a positive effect of family meals onthe infant’s diet relies on the family having healthy foodsthat are also suitable for the infant [18].

Favourable effects on parental feeding practicesOne area of recent interest concerns the role that paren-tal feeding practices may play in promoting excessiveweight gain in very young children [27, 29, 30]. Exertinggreater control over a young child’s food intake is

Daniels et al. BMC Pediatrics (2015) 15:179 Page 3 of 15

thought to negatively impact on the child’s ability toregulate their energy intake. Certainly parents who fol-low BLW have reported lower levels of restriction, pres-sure to eat and monitoring of the child’s food intake andare less concerned about the child’s body weight [21].However, it is not clear whether parents with these char-acteristics are more likely to choose, or to persist withBLW, or whether BLW encourages the development ofthese characteristics. Longitudinal or intervention stud-ies are needed to help determine the direction of thisassociation.

More highly developed motor skillsCarruth and Skinner [31] have suggested that some feed-ing behaviours may be achieved later by children whoseparents limit their opportunities to explore during feed-ing time, perhaps because of concerns about mess andspills [31]. They suggest that some parents may needmore encouragement to allow their child to engage inactivities relating to feeding in order to help their childdevelop feeding skills [31]. The ability of children tolearn to self-feed depends, therefore, not so much on theinnate development of fine, gross and oral motor skills,but on the opportunity to develop these skills throughapplying them repeatedly [31]. We hypothesize that ababy-led approach to complementary feeding would pro-vide an infant with greater opportunities (both in fre-quency and duration) to develop their gross and finemotor skills.

Potential disadvantages of Baby-Led WeaningSeveral concerns have also been raised about this alter-native approach to complementary feeding; namely thatBLW could increase the risk of iron deficiency, chokingand growth faltering in infants [12, 18, 23].

Iron deficiencyIt is important that complementary foods high in ironare introduced at 6 months of age in order to maintainadequate iron status [8]. Iron deficiency, a common nu-tritional deficiency globally, can lead to iron deficiencyanaemia which is associated with delays in cognitivefunction that may not be reversible [32].Unfortunately, the most common ‘first foods’ intro-

duced to infants, including fruits and vegetables, are nat-urally low in iron. Iron-fortified infant cereals can be animportant source of iron for this age group [33], how-ever they are not likely to be consumed by infants fol-lowing BLW because infants of this age will find itdifficult to feed themselves this relatively liquid food.Iron rich foods such as red meat may be served in formsthat can be easily picked up by a 6 month old so may beuseful foods to feed from the start of complementaryfeeding [19, 34], as long as they are not avoided due to

parental concerns about choking. To date, no studieshave examined either the iron intake or iron status ofchildren following a baby-led approach to complemen-tary feeding.

ChokingChoking can easily occur in infants learning to eat asthey are experimenting with moving foods around themouth, biting and chewing and they also have small airpassages [8]. The potential for choking to occur whenfollowing BLW is of considerable concern amongsthealth professionals and parents [18]. There are cur-rently very few data on the rates of choking during thecomplementary feeding period, and no data on chokingin infants following BLW. However, Cameron et al. [18]found 30 % of a group of women using BLW with theirinfants (n = 20) reported an episode of choking. This wascaused by consumption of raw apple in all cases wherethe mother was able to recall the food responsible.

Growth falteringIn the first year of life, the majority of infants receivemost of their energy from breast milk (or infant formula)[35]. However, complementary foods are an importantsource of energy and many nutrients in the second6 months of life [8, 35]. Some health professionals haveexpressed concern that infants following BLW may be atincreased risk of growth faltering, based on the assump-tion that not all infants will have the motor skills, or mo-tivation, to feed themselves the amount of food theyrequire, and that many of the first foods offered will below in energy [15]. However, only two cross-sectionalstudies appear to have examined growth in infants fol-lowing BLW [17, 28]. Townsend and Pitchford [17]found an association between weaning style and infantsclassified as underweight. Infants whose parents re-ported having followed BLW had a higher prevalence ofunderweight (4.8 %) than infants whose parents reportedfollowing a spoon-fed approach to complementary feed-ing (0 %) [17]. Similarly, Brown et al. [28] found a higherprevalence of underweight in their BLW group (5.4 %)compared with their standard complementary feedinggroup (2.5 %). However, both studies were limited bytheir cross-sectional design, the small numbers of partic-ipants classified as underweight (n = 3-11), parents retro-spectively self-reporting the type of complementaryfeeding method they had used and recruitment of BLWand control groups from different sources.

Other potential disadvantagesBecause of the limited research conducted on BLW, it isnot known whether BLW poses any risks for nutrientsother than iron (which is discussed above). In particular,zinc is found in limited amounts in foods that may be

Daniels et al. BMC Pediatrics (2015) 15:179 Page 4 of 15

used as first foods in BLW, such as fruit and vegetables,because they are easy to self-feed. Poorer zinc statuscould have implications for growth, motor and cognitivedevelopment, and immune function [36].Concerns have also been expressed that family foods

may not always be suitable for infants if the family isconsuming meals high in sugar or salt [15], both ofwhich are inappropriate for infants [8]. Family foods of-fered to infants must be suitable, both because of theimmediate risk to infant health and because the infantmay become accustomed to salt and sugar tastes, poten-tially predisposing them to poorer diets in later life andtherefore poorer health outcomes in adulthood.

SummaryAlthough a baby-led approach to complementary feedingappears to have many potential advantages, there are stillmany unanswered questions, in particular:

– What impact does it have on the growth anddevelopment of infants?

– Do infants consume foods containing sufficientmicronutrients?

– Does it affect the quality of infants’ diets overall?– Does it alter parental feeding behaviours?– Is it safe?– Is this alternative method of complementary feeding

acceptable to parents?

There are currently very limited longitudinal data andno randomised controlled trials investigating a baby-ledapproach to complementary feeding. A randomised con-trolled trial is urgently needed in order to determine theanswers to these questions, both because an increasingnumber of parents are choosing to follow BLW, and be-cause, if a baby-led approach to complementary feedingproves to be protective against excess weight gain in in-fancy, it is essential to know whether it is both safe forinfants and acceptable for parents, before it can be advo-cated as a public health intervention.

Aims and objectivesThe aim of the BLISS study is to determine whether anovel approach to complementary feeding using foodsthat an infant can feed themselves - ‘Baby-Led Introduc-tion to SolidS’ (BLISS) - prevents overweight in youngchildren by improving energy self-regulation, without in-creasing the risk of iron deficiency, choking and growthfaltering.The primary objective of the BLISS study is to deter-

mine whether BLISS improves weight status (BMI-for-age z-score) at 12 months of age. Secondary objectivesare to determine whether BLISS:

(i) improves energy self-regulation at 12 months(ii) improves iron and zinc intake and status at

12 months(iii) improves diet quality at 7 and 12 months(iv) impacts favourably on parental feeding behaviours

at 12 months(v) results in more highly developed motor skills at 6, 8

and 12 months(vi) is an acceptable option for parents (mess, overall

acceptability, adherence) at 7–9 months; or(vii) is not an acceptable approach to infant feeding

because it increases the risk of choking or growthfaltering between 6 and 12 months of age

(viii) improves weight status, energy self-regulation, dietquality, parental feeding behaviours and infant motorskills at follow up at 24 months of age.

Methods/DesignStudy designThe Baby-Led Introduction to SolidS (BLISS) study is a2-arm randomised controlled trial (Fig. 1), commencingin late pregnancy. Expectant mothers in their third tri-mester of pregnancy will be randomised into one of twogroups: control group - accessing standard care; or theBLISS (intervention) group - offered BLISS advice inaddition to accessing standard care. The study will con-sist of a 12-month intervention phase with the main out-comes at 12 months of age and a planned follow up at2 years of age.The study has been approved by the Lower South

Regional Ethics Committee (LRS/11/09/037) and isregistered with the Australian New Zealand ClinicalTrials Registry ACTRN12612001133820. Written in-formed consent will be obtained from all participantsbefore randomisation.

Participants and recruitmentAll pregnant women booked into the Queen Mary Ma-ternity Unit, Dunedin Hospital (Dunedin, New Zealand),will be invited to participate in the BLISS study duringthe third trimester of pregnancy. There are no otherbirthing facilities in Dunedin (population 120,000) andthe number of home births is <3 %. Each woman will re-ceive a letter that acknowledges their booking into thematernity unit and provides them with initial informa-tion about the study. Women requesting home birthswill be given similar information regarding the studyfrom their Lead Maternity Carer (LMC; all mothers inNew Zealand choose a LMC, usually a midwife, who isresponsible for their pregnancy-related health care frompregnancy to approximately 6 weeks after birth). Just be-fore 28 weeks gestation, the prospective participant’sLMC will be contacted to ensure that invitation lettersare not sent to women who have miscarried. At 28 weeks

Daniels et al. BMC Pediatrics (2015) 15:179 Page 5 of 15

gestation, the prospective participant will receive a letterinviting them to take part in the study. This letter con-tains an opt-out phone number for an answerphonewhere the woman can leave a message advising if theydo not wish to participate. Research staff will contactwomen who do not opt-out within 2 weeks to establisheligibility, explain the purpose of the study, answer anyquestions and if they are interested in participating,

organise a time for an individual meeting so that thewoman can give written informed consent to participate.

Inclusion criteriaWomen will be eligible to participate if they: book intothe birthing unit at Queen Mary Maternity Hospital be-fore 34 weeks gestation (those women who have chosena home birth will be considered eligible if their midwife

Fig. 1 Study design

Daniels et al. BMC Pediatrics (2015) 15:179 Page 6 of 15

notifies the study before 34 weeks gestation); speak Eng-lish or Te Reo Māori (the official language of the indi-genous people of New Zealand); plan to live in theDunedin, New Zealand, area until their child is at least2 years of age; and are 16 years of age or older.

Exclusion criteriaAfter birth, women will be excluded if their infant isborn before 37 weeks gestation; or if a congenital abnor-mality, physical condition, or intellectual disability,which is likely to affect the infant’s feeding or growth isidentified.

Sample sizeReference data for sample size calculations for our pri-mary aim were obtained from our ongoing Prevention ofOverweight in Infancy study for which we have data ongrowth from 0 to 12 months in 491 participants [37].Using a mean (standard deviation) of 17.3 kg/m2 (1.4)and a correlation between repeated measures (BMI at 6and 12 months) of 0.78, our study has 80 % power at the5 % level of significance to detect a difference in BMI of0.40 kg/m2 (25 % of a standard deviation) with 85 in-fants in each group. Comparable differences have beenobserved in other obesity prevention initiatives duringinfancy [38].Sample sizes for selected secondary objectives for

which appropriate data were available (power 80 %, sig-nificance 5 %) range from 63 to 84 as shown in Table 2.We will recruit 200 participants, which allows for a

15 % drop-out for the primary objective and providessufficient participants for the secondary objectives listedin Table 2.

RandomisationThe participants will be randomised into one of the twostudy groups using numbers from random length blocks,after stratification for parity (including the current preg-nancy: 1 child vs >1 child) and education (non tertiaryvs tertiary), as these may affect responsiveness to theintervention. Research staff will open the next consecu-tive opaque, pre-sealed envelope in the stratum to whichthe participant belongs and inform the participant whichgroup they have been assigned to. All outcome assess-ment data will be collected by research staff blinded togroup allocation.

Study groupsAll participants will receive standard Well Child care (a na-tionally funded health care programme for children under5 years of age [39]) from the LMC and then Well Childagency of their choice. These free home and clinic visitsprovide advice on feeding, sleep and safety; and assessgrowth and development, hearing, vision and wellness forall children within New Zealand. Visits are typically sched-uled for: birth, 1 week, 2–4 weeks, and 4–6 weeks (pro-vided by an LMC – typically a community-based midwife);and 8–10 weeks, 3–4 months, 5–7 months, 9–12 months,15–18 months, and 2–3 years (typically provided by a WellChild nurse) [39].

Control groupParticipants randomised to the control group will receivestandard Well Child care (as described above) from theproviders of their choice and no additional intervention.

BLISS groupParticipants randomised to the BLISS group will receivestandard Well Child care (as described above) from theproviders of their choice, as well as additional parent con-tacts for support and education from before birth to9 months of age delivered by the BLISS study. The inter-vention will be delivered by an experienced lactation con-sultant and trained research staff who will be supervised bya multidisciplinary team (dietitian, paediatrician, speech-language therapist) throughout the study. The interventionhas three key components:Professional lactation consultant service (third tri-

mester of pregnancy to 6 months of age) - There will beat least five contacts with an International Board Certi-fied Lactation Consultant (IBCLC):

a) An anticipatory guidance group session beforebirth (at approximately 34–35 weeks gestation) todiscuss breastfeeding (benefits, challenges anddeveloping a “breastfeeding plan”), explain thenature of the free support service on offer untiltheir infant is 6 months of age and introduce theconcept of Baby-Led Introduction to SolidS.

b) A home visit in the first week after the motherreturns home from hospital, or during the firstweek following a planned homebirth; a supportphone call and offer of a home visit at 3–4

Table 2 Sample size calculations for secondary outcomes

Reference data Source of reference data Difference detecteda Number needed per group

Mean (SD)

Energy self-regulation scale 3.9 (0.8) [45] 0.4 63

Plasma ferritin (μg/L) 16.0 (0.6) [65] 5.0 84a The difference that could be detected with 80 % power and a significance level of 5 %

Daniels et al. BMC Pediatrics (2015) 15:179 Page 7 of 15

weeks; a home visit at 3–4 months; and a phonecall at 5 months of age, to provide support andeducation around breastfeeding (or formulafeeding if requested), and to assess how therecommended approach of milk only until6 months is going. Support will includeencouraging: exclusive breastfeeding to 6 months,breastfeeding to at least 12 months and delayingthe introduction of complementary foods until6 months of age.

c) The lactation consultant will also be available tosupply additional support when requested by theparticipant until her infant is 6 months of age. Thiswill involve providing specific individualized adviceto address problems with breastfeeding (or formulafeeding) via extra home visit(s), phone or emailcontact. In our earlier Prevention of Overweight inInfancy study [37], this additional support wasutilized by 36 % of families (Davies, personalcommunication).

BLISS advice (5.5–9 months of age) – There will beat least three contacts with a trained researcher.

a) A home visit at 5.5, 7 and 9 months of age providingindividualized advice and support for the introductionof complementary foods using the BLISS approach.Parent participants will be advised that they must notstart BLISS until their infant is 180 days (i.e. 6 monthsof age). Research staff will encourage responsivefeeding [40], ensuring that: the infant is not distractedwhile eating, and caregivers pay attention to the infant’shunger and satiety cues and respond to the infantpromptly and supportively. Parents will be encouragedto offer “easy” foods and more frequent milk feedsduring both illness and recovery [1]. A range ofresources will be given to participants explaining howto follow BLISS and providing age-appropriate familyrecipes (see below).

b) The researcher will also be available to provideadditional support when requested by theparticipant.

BLISS resources (third trimester of pregnancy to9 months of age) - A range of resources developedand pretested for the purposes of this study will beprovided to the participants, including informationabout the BLISS study, recipe books, everyday foodlists and safety information [41]. These resources fol-low the philosophy of BLW but also address the threekey concerns that some health professionals haveexpressed about BLW [18]: inadequate iron intake,choking and growth faltering. All resources have beendeveloped in conjunction with a paediatric speech-

language therapist to address concerns about choking.In particular, the resources encourage parents to:

a) Test foods before they are offered to ensure they aresoft enough to mash with the tongue on the roof ofthe mouth (or are large and fibrous enough thatsmall pieces do not break off when sucked andchewed, e.g., strips of meat).

b) Avoid offering foods that form a crumb in themouth.

c) Make sure that the foods offered are at least as longas the child’s fist, on at least one side of the food.

d) Make sure the infant is always sitting upright whenthey are eating – never leaning backwards.

e) Always have an adult with the child when they areeating.

f ) Never put whole foods into the infant’s mouth – theinfant must do this at their own pace and undertheir own control.

Parents will be encouraged to offer three food types ateach meal:

1. An iron-rich food (e.g., red meat, iron fortified infantcereal).

2. An energy-rich food.3. A food such as a fruit or vegetable.

A range of resources will be used at the different visits:ante-natal (n = 1), 3–4 months (n = 1), 5.5 months (n = 6),7 months (n = 2) and 9 months (n = 1). Figure 2 shows anexample of a resource – the “BLISS in a nutshell” resourcewhich is used (at the 5.5 month visit) to provide an overallsummary of the BLISS approach to complementaryfeeding from 6 months of age and which parents areencouraged to use to help explain BLISS to their infant’sother carers.

AdherenceAdherence to infant self-feeding will be determinedusing data provided in the 3-day diet record on whofed the child each food (child, parent, or both) for3 days over a period of a month. This will providevery detailed data on adherence collected in “real-time”. However, it is likely that not all participantswill complete all 3 days of diet recording. For thisreason, we will also use a brief (5–10 min) feedingquestionnaire at 2, 4, 6, 7, 8, 9 and 12 months to as-sess adherence to self-feeding. Adherence to the rec-ommendation to exclusively breastfeed to 6 months,and to introduce complementary foods at 6 months,will also be determined using the brief feeding ques-tionnaires at 2, 4, 6, 7, 8, 9 and 12 months.

Daniels et al. BMC Pediatrics (2015) 15:179 Page 8 of 15

Fig. 2 BLISS in a Nutshell

Daniels et al. BMC Pediatrics (2015) 15:179 Page 9 of 15

Outcome measuresThe timing of the outcome measures is presented inTable 3. The primary outcome measure is BMI-for-agez-score (calculated using body weight and length). Sec-ondary outcome measures include: energy self-regulation, iron and zinc intake and status, diet quality,parental feeding behaviour, overall acceptability, choking,and growth faltering.

Anthropometric measuresBirth weight will be accessed from hospital records.Length will be measured at 6 and 12 months and bodyweight at 6, 7, 8, 9 and 12 months of age by trainedanthropometrists, using standard paediatric anthropo-metric techniques [42]. All infant participants will weara standard nappy of known weight which is provided tothe parent and a singlet top. The weight of both items ofclothing will be subtracted from the reported bodyweight before analysis. Body weight will be measuredand recorded to the nearest 0.1 kg using digital scales(Seca, Model 334, Hamburg, Germany), which will becalibrated (using a 1 kg or 5 kg calibration weight) priorto each measurement session. Recumbent length will bemeasured to the nearest 0.1 cm using a portable lengthboard (Harlow Healthcare Rollameter, UK) which will becalibrated (using a 90 cm calibration rod) prior to eachmeasurement session.Body weight and length measurements will be taken in

duplicate and if the second measurement differs by more

than 0.1 kg for weight and 0.7 cm for length, a thirdmeasure will be taken [42]. An average of the measureswill be recorded (where there are three measurementstaken, the two closest will be averaged; where the threemeasures are equidistant the median value will be used).The following will then be calculated: BMI and BMI-for-age z-score at 6 and 12 months of age, and weight-for-age z-score at 6, 7, 8, 9 and 12 months of age, using theWHO child growth standards [43].Repeated body weight assessment of infants from 6 to

12 months (monthly from 6 to 9 months) will be used toidentify growth faltering. Any infant identified as pos-sibly growth faltering (defined as either (a) weight nothaving increased since the previous measurement, or (b)the difference in weight-for-age z-score between thismeasurement and the previous one (or the measurementat 6 months) being more negative than -1) will be re-ferred to a paediatrician for further assessment. Growthfaltering will be defined (using the WHO growth charts)as ‘a weight deceleration crossing more than two majorcentile lines, where the major centile lines are 2/3rds ofa standard deviation apart’.

QuestionnairesA self-administered baseline questionnaire will collectsocio-demographic information such as ethnicity, ma-ternal and paternal education, and New ZealandDeprivation Index 2013 score, an indicator of thelevel of household deprivation [44].

Table 3 Interventions and outcome measures at specified time points

Daniels et al. BMC Pediatrics (2015) 15:179 Page 10 of 15

A questionnaire will be completed by adult partici-pants when their infant is 6 and 12 months of age whichwill assess the infant’s energy self-regulation using an 8-item scale created by Tan et al. [45]. At 6, 7, 8, 9 and12 months, questions regarding cup or bottle emptyingwill be used as an indicator of self-regulation of milk in-take for those who are offered infant formula orexpressed breast milk [46].Infant temperament will be assessed at 6 months of

age using the revised infant temperament question-naire [47]. The ‘Ages and Stages’ questionnaire [48]will be used in questionnaires at 6, 8 and 12 monthsof age to assess fine and gross motor skills. Parentalfeeding behaviour and perception of “picky eating”will be assessed when the infant is 12 months of age[49]. Eating behaviour will also be assessed at12 months using the Children’s Eating BehaviourQuestionnaire by Wardle et al. [50].Brief feeding questionnaires will be administered at 7,

8, 9 and 12 months of age to assess a range of issues in-cluding the acceptability to parents of the complemen-tary feeding approach used. Acceptability will focusparticularly on “mess”, convenience, cost and the extentto which the approach “suits you as a parent”. At 8 and9 months, the primary carer will also be asked abouttheir perception of their partner’s attitude to the com-plementary feeding approach used.

ChokingQuestions on gagging and choking, including frequencyand a description of the cause and outcome of the mostserious choking event in the past month, will be askedin questionnaires at 6, 7, 8, 9 and 12 months of age.Calendars will also be distributed to parents at 6 and

8 months of age and parents will be asked to indicate onthe calendar, each day for a month, whether the infanthas gagged or choked that day. Education will be pro-vided on the difference between gagging and choking tohelp parents distinguish between them. If a choking epi-sode occurs, further information will be requested in-cluding the food or drink involved, the form of the foodor drink and how the choking episode was resolved.

Dietary assessmentThe parent will complete a 3-day weighed diet recordfor the infant at 7 and 12 months of age. Dietary scalesaccurate to ±1 g (Salter Electronic, Salter HousewaresLtd. Tonbridge, UK) will be used to measure all foodand drink consumed by the infant on three randomlyassigned non-consecutive days of the week (2 week daysand 1 weekend day) over a 3-week period. Each day ofthe week will be represented an approximately equalnumber of times among participants to control for day-of-the-week effects. Parents will receive detailed oral and

written instructions from trained research staff on howto complete the 3-day diet record.The diet record will have four key components: (a) the

diet record, where information will be recorded regard-ing the time of the day, type and brand of the food ordrink, preparation method, weight of the food or drink,consistency of the food or drink (puréed, mashed, dicedor whole), who fed the child (parent, child or both) andthe total weight and estimated proportions of leftoverfood or drink; (b) a description of any recipes used, in-cluding the raw amounts of ingredients, the cookingmethod and proportion of the total recipe fed to thechild; (c) an “end of day questionnaire”, which will deter-mine whether this was a typical eating day for the childand how the meals compared to those consumed by therest of the family; and (d) whether the child had any ironor zinc containing supplements, including type, brandand amount taken.On completion of the 3-day diet record, a re-

searcher will check the record for omissions and clar-ify these with the parent. All diet records will beentered into the dietary analysis software programmeKai-culator (University of Otago, New Zealand) foranalysis. Kai-culator uses the New Zealand FoodComposition Database, FOODfiles [51]; nutrient datafor commonly consumed recipes collated in the 2008/09 New Zealand Adult Nutrition Survey [52]; and nu-trient data for commercial infant foods collated bythe research team [53].The diet records will be used to determine mean daily

intakes of nutrients and food components including: en-ergy, protein, fat, carbohydrate, iron, zinc and phytate;phytate-to-zinc and phytate-to-iron molar ratios [54];grams of red meat (beef and lamb) and all flesh foods(red meat, non-red meat, poultry and fish); and iron andzinc from different food sources.

Biochemical assessmentAt 12 months of age a non-fasting venous blood samplewill be taken from an antecubital vein between 8:30 and11:30 am. A questionnaire will be completed 24 h beforethe blood test appointment to determine any recent ill-ness which may affect blood analyses. If the infant is un-well (presence of fever, diarrhoea or vomiting), the bloodsample collection will be delayed for 14 days.Parents will be asked to:

a) Give their infant a milk feed and stop feeding exactly90 min prior to the blood test appointment [55].

b) Not give their infant any other food or fluid (exceptwater) until after the blood test appointment.

c) Apply a local anaesthetic, Ametop gel (Smith &Nephew Ltd., Auckland, New Zealand), 1–4 h priorto the blood test appointment. The gel is to be

Daniels et al. BMC Pediatrics (2015) 15:179 Page 11 of 15

applied to the inside elbow crease of both arms tonumb the phlebotomy site, and so that if the initialattempt is unsuccessful, the blood sample can becollected from the other arm.

A trained phlebotomist will collect one peripheralvenipuncture blood sample (7.5 mL) from each infantparticipant into a trace element-free lithium heparinanticoagulated tube (Sarstedt S-Monovette, Nümbrecht,Germany). Blood samples will be refrigerated immedi-ately after collection and for no longer than 2 hours be-fore centrifuging at 2500 × g for 10 min. Beforecentrifuging, 1 mL of whole blood will be removed foranalysis of complete blood count and plasma ferritin. Al-iquots of plasma will then be stored at −80 °C until sub-sequent analysis of soluble transferrin receptor (sTfR),C-reactive protein (CRP), α-1 acid glycoprotein (AGP)and plasma zinc. A Cobas C311 automatic electronicanalyzer (Roche, New Zealand) will be used to determinesTfR, CRP and AGP concentrations in the Departmentof Human Nutrition Trace Element Laboratory (Univer-sity of Otago, New Zealand).Complete blood count will be determined using a Sys-

mex XE 5000 automatic electronic analyzer (Kobe,Japan) and plasma ferritin concentration using a Cobas8000 unit e 602 (Roche, United States of America) onthe day of blood collection by Southern Community La-boratories Ltd. (Dunedin, New Zealand).Any infant with iron results that are of concern

(haemoglobin ≤105 g/L and/or plasma ferritin ≤15 ug/L)will be referred to their general practitioner for treat-ment but will remain in the study so they can be in-cluded in the intention to treat analysis.The International Zinc Nutrition Consultative Group

(IZiNCG) protocol for measuring plasma zinc concentra-tion will be followed [56] ensuring that trace element freetechniques are used throughout – from sample collectionto analysis. Plasma zinc concentration will be determinedusing flame atomic absorption spectrophotometry(ContraAA 700, Analytik Jena, Germany) in theDepartment of Human Nutrition Trace ElementLaboratory (University of Otago, New Zealand).A CRP of >5 mg/L will be used as an index of acute

inflammation and an α-1 acid glycoprotein concentra-tion of >1 g/L as an index of chronic inflammation [57].Soluble transferrin receptor will be converted to beequivalent with the Flowers assay using the followingequation: Flowers sTfR = 1.5 × Roche sTfR + 0.35 mg/L[58] then body iron will be calculated as the log ratio ofsTfR to plasma ferritin concentration [58]. Iron deficiencywill be defined as a body iron concentration <0 mg/kg,and iron deficiency anaemia as iron deficiency and haemo-globin <110 g/L. Low iron stores will be defined as bodyiron ≥0 mg/kg and serum ferritin concentration <12 μg/L.

A plasma zinc <9.9 μmol/L will be used to define zinc de-ficiency [56].

Adverse eventsThe study will identify and monitor adverse events (de-fined as any untoward or unfavourable medical occur-rence in a participant, including any abnormal sign,symptom, or disease, temporally associated with the par-ticipant’s participation in the research, whether or not it isconsidered to be related to the participant’s participationin the study) and “serious adverse events” (defined as anyadverse event temporally associated with the participant’sparticipation in the BLISS study that results in death, islife-threatening, requires inpatient hospitalization, resultsin a persistent or significant disability or incapacity, anyother adverse event that, based upon appropriate medicaljudgment, may jeopardize the participant’s health and mayrequire medical or surgical intervention to prevent one ofthe other outcomes listed) [59].Specific arrangements will be in place for immediate

investigation and referral to the study’s paediatric clini-cians of choking episodes (reported directly by the par-ticipant, or where the involvement of a healthprofessional for a choking incident is reported in theCalendar or in study questionnaires) and growth falter-ing (identified during the 6, 7, 8, 9 and 12 month an-thropometric measurement sessions).Care will also be taken to identify and investigate: (a)

multiple occurrences of the same adverse event in thesame participant, (b) occurrence of different adverseevents in the same participant, (c) occurrence of thesame adverse event in multiple participants.

Quality controlMeasures will be put in place during the course of thestudy to ensure that the information provided to partici-pants is standardized, that data collected are of highquality and that data collection is as complete aspossible.

Standard operating procedures – Detailed protocolswill be developed and used for all study-related tasksincluding participant contacts and data managementtasks.Observed interviews – Research staff will be observedby the investigators of the study twice yearly to ensurethat the standard operating procedures are beingfollowed.Data audits - Every 3 months a data audit will beconducted to check for completeness of collected data.Technical error of measurement – Inter-evaluatortechnical error of measurement (TEM) will be deter-mined for all research staff who are responsible formaking anthropometric measurements, after initial

Daniels et al. BMC Pediatrics (2015) 15:179 Page 12 of 15

training and then annually. The TEM will be deter-mined by repeated anthropometric measurements on aseparate sample of 5–10 infants [60].Checking of weighed diet records – Diet records willbe checked when they are received. If any data aremissing or unclear the participant will be contacted forclarification. After the diet records have been enteredin Kai-culator, a New Zealand Registered Dietitian willcheck each diet record and correct any errors made inthe initial calculation and entry of the record, and en-sure consistency in the data entry decisions.Biomarkers ─ The precision of the biochemical assayswill be checked using a pooled plasma sample and theiraccuracy via the use of certified reference materials ormanufacturer’s controls, where appropriate.

Follow-up at 24 months of ageParticipants will be followed up when the child partici-pant is 24 months of age. The follow up will consist ofanthropometric measurements, a 3-day diet record anda comprehensive questionnaire assessing most of thevariables outlined previously (energy self-regulation, par-ental feeding practices, infant fine and gross motor skills,perception of “picky eating” and acceptability of thecomplementary feeding approach - all as describedabove).

Statistical analysisThe initial analyses will be conducted using intention totreat. The primary analysis will determine whetherBLISS results in differences in BMI-for-age z-score at12 months of age (i.e. at the end of the intervention) and24 months (i.e. at the end of the planned follow up) ofage. Regression analyses will be used to analyze second-ary outcomes including iron and zinc intake and status.All plasma zinc analyses will control for time of day,fasting status and time of last food/drink. We will con-sider adjusting plasma ferritin and zinc concentrationswhere there is evidence of infection or inflammation, in-dicated by elevated C-reactive protein or α-1 acid glyco-protein [57, 61]. Statistical significance will be defined asP <0.05.Subsequent to this we will also do a per protocol ana-

lysis in order to identify any differences to the intentionto treat analysis, which may occur because of differentialcompliance with the research protocol.

DiscussionWith the increasing popularity of BLW amongst parentsand interest from health professionals who need to pro-vide evidence-based advice to parents on how to safelyintroduce complementary foods, there is an urgent needfor data on the potential benefits and risks of a baby-ledapproach to complementary feeding. To our knowledge,

this is the first randomised controlled trial of a baby-ledapproach to complementary feeding so it will generatemuch new evidence in the area of infant feeding, par-ticularly during the second 6 months of life. While somegovernments are already modifying their advice on themost appropriate texture for first foods [13, 14, 62],countries such as New Zealand are waiting for evidencefrom well-designed randomised controlled trials.The primary aim of this intervention study is to deter-

mine whether a baby-led approach to complementaryfeeding can improve body weight status at 12 months ofage. With childhood obesity rates growing worldwide[63], the study will provide insight into the developmentand establishment of eating patterns from the start ofthe complementary feeding period and their effect onbody weight during infancy and early childhood. Wehypothesize that self-feeding throughout the comple-mentary feeding period may help infants maintain anddevelop the energy self-regulation skills they have devel-oped while exclusively milk-feeding [64] and that thisbehaviour will continue into later childhood.The BLISS study will also investigate the potential

negative effects of BLW and determine whether thismodified approach, BLISS, is able to prevent iron defi-ciency and minimize any risk of choking or growth fal-tering. This information is extremely important both toenable health professionals to advise parents who wouldlike to follow a baby-led approach to complementaryfeeding and to advise policy-makers on whether this ap-proach should replace current advice on complementaryfeeding for parents in general.

AbbreviationsBLISS: Baby-Led Introduction to SolidS; BLW: Baby-Led Weaning; BMI: bodymass index; CRP: C-reactive protein; IBCLC: International Board CertifiedLactation Consultant; IZiNCG: International Zinc Nutrition Consultative Group;LMC: lead maternity carer; sTfR: soluble transferrin receptor; UK: UnitedKingdom; WHO: World Health Organization.

Competing interestsThe study is partially funded by Meat & Livestock Australia. The authorsdeclare no conflicts of interest.

Authors’ contributionsAL MH and RWT are the co-Principal Investigators of the BLISS study anddesigned the research project, applied for funding and made a considerableintellectual contribution to the writing of this manuscript. LD contributed tothe design of the blood sample methods and prepared the first full draft ofthis manuscript. SMW advised on study design, sample size analysis and thestatistical design. SLC developed the BLISS resources and applied for ethicalapproval. LAF, RSG, BJT and BJW provided expert input into the design ofthe study and ongoing advice and support. All authors have made an im-portant intellectual contribution to the manuscript and have read andapproved the final manuscript.

AcknowledgementsWe would like to acknowledge the following people who contributed to thedevelopment of this study including members of the BLISS team: RhonddaDavies, Jenny McArthur, Brittany Morison, Elizabeth Williams, Louise Fangupoand Sabina Bacchus; and Speech-Language Therapists Lisa Gallagher and

Daniels et al. BMC Pediatrics (2015) 15:179 Page 13 of 15

Siobhan McKinlay from CARA (Community Assessment and RehabilitationAssociates) Ltd (Dunedin, New Zealand).

FundersLottery Health Research, Meat & Livestock Australia, The New ZealandWomen’s Institute, Karitane Products Society, Perpetual Trustees, University ofOtago. RWT is supported by a Fellowship from Karitane Products Society. LDis supported by a University of Otago Doctoral Scholarship.

Author details1Department of Human Nutrition, University of Otago, PO Box 56, Dunedin9054, New Zealand. 2Department of Medicine, University of Otago, PO Box56, Dunedin 9054, New Zealand. 3Department of Preventive and SocialMedicine, Dunedin School of Medicine, University of Otago, PO Box 56,Dunedin 9054, New Zealand. 4Department of Women’s and Children’sHealth, Dunedin School of Medicine, University of Otago, PO Box 56,Dunedin 9054, New Zealand. 5Edgar Diabetes and Obesity Research Centre,Dunedin School of Medicine, University of Otago, PO Box 65, Dunedin 9054,New Zealand.

Received: 6 March 2015 Accepted: 20 October 2015

References1. World Health Organization (WHO). Guiding principles of complementary

feeding of the breastfed child. Geneva: World Health Organization;2004. p. 1–38.

2. World Health Organization (WHO). Guiding principles for feeding non-breastfed children 6–24 months of age. Geneva: World Health Organization;2005. p. 1–40.

3. World Health Organization (WHO). Infant and young child feeding: modelchapter for textbooks for medical students and allied health professionals.Geneva: World Health Organization; 2009.

4. Naylor AJ, Morrow AL. Developmental readiness of normal full term infantsto progress from exclusive breastfeeding to the introduction ofcomplementary foods: Reviews of the relevant literature concerning infantimmunologic, gastrointestinal, oral motor and maternal reproductive andlactational development. Washington: The Linkages Project and WellstartInternational; 2001.

5. Agostoni C, Decsi T, Fewtrell M, Goulet O, Kolacek S, Koletzko B, et al.Complementary feeding: a commentary by the ESPGHAN committee onnutrition. J Pediatr Gastroenterol Nutr. 2008;46:99–110.

6. Prescott SL, Smith P, Tang M, Palmer DJ, Sinn J, Huntley SJ, et al. Theimportance of early complementary feeding in the development of oraltolerance: Concerns and controversies. Pediatr Allergy Immunol.2008;19:375–80.

7. Fewtrell MS, Lucas A, Morgan JB. Factors associated with weaning in fullterm and preterm infants. Arch Dis Child Fetal Neonatal Ed.2003;88:F296–301.

8. Ministry of Health (MOH). Food and nutrition guidelines for healthy infantsand toddlers (Aged 0–2): a background paper. 4th ed. Wellington: Ministryof Health; 2008.

9. United States Department of Agriculture. Infant nutrition and feeding. In:Chapter 5: Complementary foods. 2009. p. 101–28.

10. National Health and Medical Research Council (NHMRC), Department ofHealth and Ageing, Australian Government. Infant feeding guidelines:information for health workers. Canberra: National Health and MedicalResearch Council; 2012. p. 1–160.

11. Wright CM, Cameron K, Tsiaka M. Is baby-led weaning feasible? When dobabies first reach out for and eat finger foods? Matern Child Nutr.2011;7(1):27–33.

12. Rapley G. Baby-led weaning: transitioning to solid foods at the baby’s ownpace. Community Pract. 2011;84:20–3.

13. Department of Health United Kingdom (UK). Birth to five (Updated June2010). United Kingdom: Department of Health; 2009. p. 1–192.

14. Health Canada. Nutrition for healthy term infants: recommendations fromsix to 24 months. Health Canada; 2014. http://www.hc-sc.gc.ca/fn-an/nutrition/infant-nourisson/recom/recom-6-24-months-6-24-mois-eng.php

15. Cameron SL, Heath ALM, Taylor RW. How feasible is baby-led weaning as anapproach to infant feeding? A review of the evidence. Nutrients.2012;4:1575–609.

16. Arden MA, Abbott RL. Experiences of baby-led weaning: trust, control andrenegotiation. Maternal Child Nutr. 2014;11(4):829–44.

17. Townsend E, Pitchford NJ. Baby knows best? The impact of weaning styleon food preferences and body mass index in early childhood in a case-controlled sample. BMJ Open. 2012;2:e000298.

18. Cameron SL, Heath ALM, Taylor RW. Healthcare professionals’ and mothers’knowledge of, attitudes to and experiences with, Baby-Led Weaning: acontent analysis study. BMJ Open. 2012;2:1–9.

19. Cameron SL, Taylor RW, Heath ALM. Parent-led or baby-led? Associationsbetween complementary feeding practices and health-related behaviours ina survey of New Zealand families. BMJ Open. 2013;3:1–9.

20. Brown A, Lee M. A descriptive study investigating the use and nature of baby-ledweaning in a UK sample of mothers. Maternal Child Nutr. 2011;7:34–47.

21. Brown A, Lee M. Maternal control of child feeding during the weaningperiod: differences between mothers following a baby-led or standardweaning approach. Matern Child Health J. 2011;15:1265–71.

22. Rowan H, Harris C. Baby-led weaning and the family diet. A pilot study.Appetite. 2012;58:1046–9.

23. Ministry of Health (MOH). Baby-Led Weaning – Ministry position statement.Ministry of Health; 2012. http://www.health.govt.nz/our-work/preventative-health-wellness/nutrition/baby-led-weaning-ministry-position-statement.Accessed 12 May 2014.

24. Rapley G, Murkett T. Baby-Led Weaning. London: Vermilion; 2008. p. 1–256.25. Schwartz C, Scholtens PA, Lalanne A, Weenen H. Development of healthy

eating habits early in life. Review of recent evidence and selectedguidelines. Appetite. 2011;57:796–807.

26. Brown A, Lee M. An exploration of experiences of mothers following ababy-led weaning style: developmental readiness for complementary foods.Maternal Child Nutr. 2013;9:233–43.

27. Gross RS, Mendelsohn AL, Fierman AH, Messito MJ. Maternal controllingfeeding styles during early infancy. Clin Pediatr (Phila). 2011;50:1125–33.

28. Brown A, Lee MD. Early influences on child satiety-responsiveness: the roleof weaning style. Pediatr Obes. 2013;10:57–66.

29. Faith MS, Scanlon KS, Birch LL, Francis LA, Sherry B. Parent–child feedingstrategies and their relationships to child eating and weight status. ObesRes. 2004;12:1711–22.

30. Brown A, Lee M. Maternal child-feeding style during the weaning period:Association with infant weight and maternal eating style. Eat Behav.2011;12:108–11.

31. Carruth BR, Skinner JD. Feeding behaviors and other motor development inhealthy children (2-24 months). J Am Coll Nutr. 2002;21:88–96.

32. Domellöf M, Braegger C, Campoy C, Colomb V, Decsi T, Fewtrell M, et al.Iron requirements of infants and toddlers. J Pediatr Gastroenterol Nutr.2014;58:119–29.

33. Walter T, Dallman PR, Pizarro F, Velozo L, Pena G, Bartholmey SJ, et al.Effectiveness of iron-fortified infant cereal in prevention of iron-deficiencyanemia. Pediatrics. 1993;91:976–82.

34. Szymlek-Gay EA, Ferguson EL, Heath ALM, Gray AR, Gibson RS. Food-basedstrategies improve iron status in toddlers: a randomized controlled trial. AmJ Clin Nutr. 2009;90:1541–51.

35. Heinig MJ, Nommsen LA, Peerson JM, Lönnerdal B, Dewey KG. Energy andprotein intakes of breast-fed and formula-fed infants during the first year oflife and their association with growth velocity: the DARLING study. Am JClin Nutr. 1993;58:152–61.

36. Gibson R, Heath AL. Population groups at risk of zinc deficiency in Australiaand New Zealand. Nutr Diet. 2011;68:97–108.

37. Taylor BJ, Heath ALM, Galland BC, Gray AR, Lawrence JA, Sayers RM, et al.Prevention of Overweight in Infancy (POI.nz) study: a randomised controlledtrial of sleep, food and activity interventions for preventing overweightfrom birth. BMC Public Health. 2011;11:942.

38. Wen LM, Baur LA, Simpson JM, Rissel C, Wardle K, Flood VM. Effectiveness ofhome based early intervention on children’s BMI at age 2: randomisedcontrolled trial. BMJ. 2012;344:e3732.

39. Ministry of Health (MOH). Well Child/Tamariki Ora. Ministry of Health; 2014.http://www.health.govt.nz/your-health/services-and-support/health-care-services/well-child-tamariki-ora. Accessed 11 May 2014.

40. Black MM, Aboud FE. Responsive feeding is embedded in a theoreticalframework of responsive parenting. J Nutr. 2011;141:490–4.

41. Cameron SL. Is Baby-led Weaning a feasible method for introducingcomplementary foods to infants in New Zealand? PhD Thesis. University ofOtago, Department of Human Nutrition; 2014.

Daniels et al. BMC Pediatrics (2015) 15:179 Page 14 of 15

42. de Onis M, Onyango AW, Van den Broeck J, Chumlea WC, Martorell R.Measurement and standardization protocols for anthropometry used in theconstruction of a new international growth reference. Food Nutr Bull.2004;25:S27–36.

43. World Health Organization (WHO). WHO Child growth standards and theidentification of severe acute malnutrition in infants and children. Geneva:World Health Organization and Unicef; 2009. p. 1–11.

44. Atkinson J, Salmond C, Crampton P. NZDep2013 index of deprivation user’smanual. Wellington: Department of Public Health, University of Otago; 2014.

45. Tan CC, Holub SC. Children’s self-regulation in eating: Associations withinhibitory control and parents’ feeding behavior. J Pediatr Psychol.2011;36:340–5.

46. Li R, Fein SB, Grummer-Strawn LM. Do infants fed from bottles lack self-regulation of milk intake compared with directly breastfed infants?Pediatrics. 2010;125:e1386–e93.

47. Gartstein MA, Rothbart MK. Studying infant temperament via the revisedinfant behavior questionnaire. Infant Behav Dev. 2003;26:64–86.

48. Ages and Stages Questionnaire (ASQ-3). Brookes Publishing Co. 2015.www.agesandstages.com/asq-products/asq-3/. Accessed 3 July 2014.

49. Horodynski MA, Stommel M, Brophy-Herb H, Xie Y, Weatherspoon L. Low-income African American and Non-Hispanic white mothers’ self-efficacy,‘picky eater’ perception, and toddler fruit and vegetable consumption.Public Health Nurs. 2010;27:408–17.

50. Wardle J, Guthrie CA, Sanderson S, Rapoport L. Development of the children’seating behaviour questionnaire. J Child Psychol Psychiat. 2001;42:963–70.

51. Ministry of Health (MOH), New Zealand Institute for Plant and FoodResearch Limited. New Zealand food composition database (FOODfiles).2013. www.foodcomposition.co.nz/foodfiles. Accessed 4 July 2014.

52. Ministry of Health (MOH), University of Otago. Methodology report for the2008/09 New Zealand adult nutrition survey. Wellington: Ministry of Health; 2011.

53. Clouston A. The role of commercial processed baby foods in the diets ofNew Zealand toddlers. MDiet Thesis. University of Otago, Department ofHuman Nutrition; 2014.

54. Hotz C, Brown KH. International Zinc Nutrition Consultative Group (IZiNCG)technical document. Food Nutr Bull. 2004;25:S91–S204.

55. Arsenault JE, Wuehler SE, de Romaña DL, Penny ME, Sempertegui F, BrownKH. The time of day and the interval since previous meal are associatedwith plasma zinc concentrations and affect estimated risk of zinc deficiencyin young children in Peru and Ecuador. Eur J Clin Nutr. 2011;65:184–90.

56. International Zinc Nutrition Consultative Group (IZiNCG). IZiNCG technicalbrief 2: assessing population zinc status with serum zinc concentration.Davis, California: International Zinc Nutrition Consultative Group; 2007.

57. Thurnham DI, McCabe LD, Haldar S, Wieringa FT, Northrop-Clewes CA,McCabe GP. Adjusting plasma ferritin concentrations to remove the effectsof subclinical inflammation in the assessment of iron deficiency: a meta-analysis. Am J Clin Nutr. 2010;92:546–55.

58. Cogswell ME, Looker AC, Pfeiffer CM, Cook JD, Lacher DA, Beard JL, et al.Assessment of iron deficiency in US preschool children and nonpregnantfemales of childbearing age: National Health and Nutrition ExaminationSurvey 2003-2006. Am J Clin Nutr. 2009;89:1334–42.

59. U.S. Department of Health and Human Services. Guidance on reviewing andreporting unanticipated problems involving risks to subjects or others andadverse events. http://www.hhs.gov/ohrp/policy/advevntguid.html.Accessed 24 October 2014.

60. World Health Organization (WHO) Multicentre Growth Reference StudyGroup. Reliability of anthropometric measurements in the WHO MulticentreGrowth Reference Study. Acta Paediatr. 2006;450:38–46.

61. Brown KH, Lanata CF, Yuen ML, Peerson JM, Butron B, Lönnerdal B. Potentialmagnitude of the misclassification of a population’s trace element statusdue to infection: example from a survey of young Peruvian children. Am JClin Nutr. 1993;58:549–54.

62. Department of Health United Kingdom (UK). Birth to five. Chapter 3.Introducing your baby to solid food. 2013. p. 40–60.

63. Dinsdale H, Ridler C, Ells L. NOO National Obesity Observatory: a simpleguide to classifying body mass index in children. 2011.

64. Dewey KG, Lönnerdal B. Infant self-regulation of breast milk intake. ActaPaediatr Scand. 1986;75:893–8.

65. Soh P, Ferguson EL, McKenzie JE, Homs M, Gibson RS. Iron deficiency andrisk factors for lower iron stores in 6–24-month-old New Zealanders. Eur JClin Nutr. 2004;58:71–9.

Submit your next manuscript to BioMed Centraland take full advantage of:

• Convenient online submission

• Thorough peer review

• No space constraints or color figure charges

• Immediate publication on acceptance

• Inclusion in PubMed, CAS, Scopus and Google Scholar

• Research which is freely available for redistribution

Submit your manuscript at www.biomedcentral.com/submit

Daniels et al. BMC Pediatrics (2015) 15:179 Page 15 of 15