Tom Baranowski, PhD - National Academies of …/media/Files/Activity...IOM-Committee on School...

IOM-Committee on School NutritionJanuary 28, 2009

Tom Baranowski, PhDProfessor of Pediatrics

(Behavioral Nutrition & PA)USDA/ARS Children’s Nutrition Research Center

Baylor College of MedicineHouston, Texas, 77030, USA


School Physical Activity Change Interventions

School Dietary Change Interventions

School Obesity Prevention Interventions□ F□ D□ C□ B□ A √ √

□ F□ D□ C□ B□ A √ √

□ F□ D□ C□ B□ A √ √


} Not a lack of consumer knowledge◦ Most children/people know they should be

eating more FV, less sugar, less fat◦ Informing about the nutrient characteristics

of foods likely will bore peopleñ “Model of enlightened self interest” likely doesn’t

work in regard to dietary intake} Few RCTs providing “best practices”} We need to find/understand the influences on

behavior (mediators), and learn how to change them


Intervention(s)Intervention(s)

Mediating Variable(s)Mediating Variable(s)

Health Outcome(s)Health Outcome(s)

Behavioral Outcome(s)Behavioral Outcome(s)

Moderating Variable(s)Moderating Variable(s)


} Assumptions◦ Behaviors are strongly causally related to health

outcomesñ If not causal – no effect on health outcomeñ If weakly related – weak effect on health outcome

◦ Mediators are strongly causally related to behaviorsñ Same rationales

◦ Interventions can induce enough change in mediators to have enough influence downstream on behaviors and health outcomesñ Relations are multiplicative


Behavioral OutcomesBehavioral Outcomes

Health OutcomesHealth Outcomes

} Not clear what percentages of obesity are due to diverse causes

} Not clear how causes interrelate} Not clear that diet & PA changes alone can

overcome some of the biological causes} Need research that looks at interrelationships

of diet and biological influences


} Taste} Cost} Convenience




} Personal characteristics ◦ Food preferences [marketers’ taste?]

(what?)◦ Skills & self efficacy (what?)ñ Eating – overcoming barriers – asking




} Situational characteristics◦ Hunger- eat many things if sufficiently

hungry (what? And how much?)◦ Availability [reflects cost?]ñ Desired food presentñ Undesired foods not




} Situational characteristics ◦ Accessibility – available in a form easy to eat

[marketers’ convenience] (what? And how much?)

◦ Portion size served [“mindless eating”] (how much?)

◦ Distractions → media/TV (how much?)




} Age & food differences in influences on intake for Elementary school?◦ Fruit/Juiceñ Home food availabilityñ Subjective normsñ Positive outcome experiences

◦ Vegetablesñ No influences




} Age & food differences in influences on intake for High school?◦ Fruit/Juice

ñ No influences◦ Vegetables

ñ Subjective normsñ Preferencesñ Self efficacy




} Genetics/hormones → satiety/hunger (how much?)

} May be more complicated than linear additive effects◦ Preferences X availability/accessibilityñ High preferences – availability aloneñ Low preferences – availability and accessibility




Model of Influences on Home Food Availability and ConsumptionEN

VIRO

NMEN

TAL

ENVI

RONM

ENTA

L

FV Purchases- Amount- Types (fresh,

frozen, canned,

etc)

Food Store

Selection

Home FV Pantry- Chilled- Frozen- Dry“Home FV Availability”

PSYC

HOSO

CIAL

PSYC

HOSO

CIAL Food

Store Selectio

nCriteria

Comparative FV Purchase Outcome Expectancies

Social Support for Buying FV

FV Purchase Outcome

Expectancies

FV Preference

s

BEHA

VIOR

ALBE

HAVI

ORAL

FV Shopping Frequenc

y

Home FV Pantry

Management Practices

FV Shopping Practices

Meal/Snack Preparation

FV Consumptio

n

Food Store Environment/

Desserts

Socio Demographics- Income (Resources)- Education- Occupation

Social Capital

CONT

EXTU

AL/

MOD

ERAT

ING

CONT

EXTU

AL/

MOD

ERAT

ING


} We have developed measures of all these constructs◦ Validated with IRM◦ Social Support was most important in pilot

study} More research: ↑availability→↑intake?

↑accessibility→↑intake?↑socialsupport→↑availability/

accessibility?


} Possible contributing factors◦ Virus (av36, av9)◦ Toxic exposures in childhood◦ Neonatal programming◦ Diet◦ Physical activity


} What we eat has multifactorial influences◦ Each account for small percentages of the

variance◦ Influences are not additive: they

interrelate} How much we eat has multifactorial

influences◦ No one policy change is likely to be

effective


} Self control procedures◦ Goal setting, goal review, problem solving

} Among adults – “tailored messages”◦ But not clear what the effective components

are◦ No work among children – how best deliver

InterventionsInterventions



} Less TV} Videogames for health behavior change

◦ Behavioral change procedures?◦ Story?




} Procedures for promoting change are not well known◦ The step by step process for each change

procedure is not known◦ Not clear whether there are synergistic effects

among change procedures} Seems unlikely that policy changes alone

will have deep or pervasive results


} Simple prescription◦ Food availability → Offer good

→ Restrict bad◦ However, “restrictive parenting” shows:ñ Boomerang effectñ Kids tended to like and eat more of the

restricted foods


} In one of our studies eliminated soft drinks, butñ Bus drivers sold cokesñ Kids went to local fast food after schoolñ Schools lost income, etc

} Innovations should be regularly evaluated to detect UC


} Capitalize on preferences for healthier options

} Restrict, but not eliminate} Offer concommitant education programs to

build self control/make healthier choices} Start efforts earlier in development so

elimination is not perceived as restriction/deprivation


} Need for better understanding (more research) of why children eat what they do or not (better mediators: causal, highly predictive)◦ Better conceptualizations (more complex, theory

driven conceptual models incorporating ecological, behavioral and biological variables)

◦ Better research design – longitudinal research◦ Better measures – more sophisticated metric

techniques◦ More sophisticated statistical modeling


} Need for better understanding of how to promote change in mediators◦ Based on best information on influences◦ RCTs with mediators as outcomes◦ Contingency/stepped interventions◦ Mediating variable analyses of behavior

change trialsñ Publish negative results


} Need blue ribbon panel to specify/simplify current complexity of influences & change◦ Need to formulate developmentally

appropriate Nutrition Education Guidelinesñ What kinds of experiences and education

should be provided at each grade/age to maximize likelihood of healthy eating child and adult?ñ Should be updated very five years based on

latest research (just like dietary guidelines)


Thank You!MUITO OBRIGADO!

MG̀ÒI! ARIGATŌ!

MERCI BEAUCOUP!MUCHAS GRACIAS!

SERDECZNIE DZIĘKUJĘ!DANKE!

SHUKRAN!TACK SÅMYCKET!

TAKK!EFHARISTÓ!


} Principles◦ Interventions change mediators◦ Changes in mediators change behavior◦ Changes in behavior change health outcomes◦ Some interventions only work with certain

people in certain situations (moderators)◦ Mediators come from research on influences ñ Can be ecological, psychosocial, biological, all


} Behavior to obesity linkage (multifactorial)} No clear evidence dietary intakes è obesity

◦ Complex path: intake, compensation, foods not eaten in isolation, biological variables

} Likely more a lack of self control/response to satiety cues?} Differences between influences on what vs. how much eaten} Other: viruses, toxic exposures?, perinatal programming,

genes (35)


Health OutcomesHealth Outcomes


} Although a large number of studies◦ Not well thought through or designed

} Genetics ◦ Bitter taste sensitivity (related to preferences, but

not intake)◦ Sweet & fat taste preferences◦ Numbers of taste buds (influences not clear)



ModeratorsModerators


} Characteristics of the foods (not my area of research)

◦ FV: preferred crunchy, not mushy (vary by age)

◦ Innate preference for sweets} Multiple exposures to the foods (10-14 max out

preference)

◦ Not clear if there is a critical age for this





} Social ◦ Modeling (especially if say how much they enjoy)

ñ Parents, siblings, peers (vary by age?)◦ Food parenting practices (not well understood),

(vary by age?)} Media

◦ Not sure how this works – lots of ideas, little empirical support (vary by age?)





} Food preferences are a primary determinant of intake ◦ Account for relatively small percentage of the variance◦ Few mediating variable studies

} No intervention studies → ↑ preference → ↑intake } Preference may be multi-faceted

◦ Flavor/taste, texture, emotional ties, preparation methods, cognitions, habit





} Operant Theory◦ Positive rewards are more effective than punishments◦ Principles: ñ Focus on positive changes to be made, ñ Shape change (in small steps)

} Parenting Literature◦ Most influential parents: Authoritative◦ Principles: ñ High expectationsñ Warm relationships ñ Rationale communication


} Self Determination Theory◦ Promote Intrinsic Motivation◦ Principles: ñ Offer choice, ñ Fun/excitement, ñ Build confidence


} Cognitive Communication Theory◦ Principles: ñ Keep message(s) simple ñ Internally consistentñ Use many channels ñ Consistency across channelsñ Repeat oftenñ Provide rationalesñ Appeal to emotions


} Self Control◦ Focus on specific foods? On satiety?◦ Goal setting, goal review, problem solving◦ Implementation intentions (action and

coping plans)


} Self Denial (change requires not doing something you probably like, and doing something you probably don’t like or you would be doing it already)◦ Train: willing/able to say “no” to one’s

desires◦ Train: knowing when/how to say “no”◦ Building alternative acceptable behavior

patterns to minimize self denial

Tom Baranowski, PhD - National Academies of …/media/Files/Activity...IOM-Committee on School...

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