Potatoes or Bacon:Which is better for weight loss?
Potatoes or Bacon:Which is better for weight loss?
Laura Zakowski, MDLaura Zakowski, MD
ObjectivesObjectives
Compare various low carbohydrate Compare various low carbohydrate dietsdiets
Review risks of low carbohydrate dietsReview risks of low carbohydrate diets Define net carbohydratesDefine net carbohydrates Define glycemic indexDefine glycemic index Review year long weight loss studiesReview year long weight loss studies
Copyright restrictions may apply.Mokdad, A. H. et al. JAMA 2003;289:76-79.
Prevalence of Obesity and Diagnosed Diabetes Among US Adults,
1991 and 2001
55 year old female interested in weight loss
55 year old female interested in weight loss
Wants to take medications or use the Wants to take medications or use the Atkin’s dietAtkin’s diet
PMH:PMH: DiabetesDiabetes HypercholesterolemiaHypercholesterolemia HypertensionHypertension ObesityObesity
YearYear WeightWeight HgbA1cHgbA1c TxTx
19901990 242242
19911991 160160 Diet and Diet and exerciseexercise
19961996 279279 Phen-fenPhen-fen
19991999 264264 6.7%6.7% Diet and Diet and exerciseexercise
11/13/0311/13/03 248248 7.9%7.9%
Atkin’s dietAtkin’s diet
Atkin’s Dietatkins.comAtkin’s Dietatkins.com
Phase 1: InductionPhase 1: Induction 20 gm carbs20 gm carbs
Phase 2: On going weight lossPhase 2: On going weight loss Add 5 gms carbs per weekAdd 5 gms carbs per week
Phase 3: PremaintenancePhase 3: Premaintenance Add 10 gms per weekAdd 10 gms per week
Phase 4: Lifetime MaintenancePhase 4: Lifetime Maintenance Usually about 45-100 gms per dayUsually about 45-100 gms per day
“Net Carbs”“Net Carbs”
Net carbs = Net carbs =
Total carbs – (Fiber + “carbs not turned in Total carbs – (Fiber + “carbs not turned in blood glucose”)blood glucose”) MaltitolMaltitol SucraloseSucralose GlycerinGlycerin PolydextrosePolydextrose
Zone dietzoneperfect.com
Zone dietzoneperfect.com
Zone dietZone diet
Glycemic indexGlycemic index
The rate at which a carbohydrate enters The rate at which a carbohydrate enters the blood stream as glucosethe blood stream as glucose
Low glycemic index: fruits and Low glycemic index: fruits and vegetablesvegetables
High glycemic index: breads, pasta, High glycemic index: breads, pasta, grains, starchesgrains, starches
Unfavorable carbohydratesUnfavorable carbohydrates
Breads, Rice, Pasta, PotatoesBreads, Rice, Pasta, Potatoes BananasBananas CarrotsCarrots CornCorn PeasPeas PineapplePineapple WatermelonWatermelon
South Beach Dietsouthbeachdiet.com
South Beach Dietsouthbeachdiet.com
Phase 1Phase 1 Limit carbsLimit carbs No: Breads, rice, potatoes, pasta, baked goods, No: Breads, rice, potatoes, pasta, baked goods,
fruitfruit
Phase 2Phase 2 Add back carbs in moderationAdd back carbs in moderation Based on glycemic indexBased on glycemic index
Phase 3Phase 3 ““A diet for life”A diet for life”
Risks of low carbohydrate diets
Risks of low carbohydrate diets
Bone loss:Bone loss: Protein affects how calcium is handled in Protein affects how calcium is handled in
the kidneythe kidney Study over 9 weeks showed no change in:Study over 9 weeks showed no change in:
Urinary calcium excretionUrinary calcium excretion 25OH Vit D, PTH25OH Vit D, PTH
Evidence of less bone turnover in high Evidence of less bone turnover in high protein groupprotein group
Conclusion: no negative effect on CaConclusion: no negative effect on Ca
Dawson-Hughes, et al. J Clin Endocrinol Metab 2004; 89: 1169-73.
Risks of low carbohydrate diets
Risks of low carbohydrate diets
HypercholesterolemiaHypercholesterolemia Impaired hepatic and renal functionImpaired hepatic and renal function Accumulation of ketonesAccumulation of ketones Salt and water depletionSalt and water depletion ConstipationConstipation
Systematic reviewSystematic review
Randomized controlled and cross over Randomized controlled and cross over studies:studies: 7 low carb diets and 75 higher carb7 low carb diets and 75 higher carb
OK studiesOK studies 34 low carb and 130 higher carb34 low carb and 130 higher carb
None longer than 90 daysNone longer than 90 days Very limited studies of patients Very limited studies of patients
Over 50Over 50 With co-morbid illnessesWith co-morbid illnesses
Bravata, et al. JAMA2003;289:1837-50
Systematic reviewSystematic review
No evidence of adverse effects onNo evidence of adverse effects on Serum lipidsSerum lipids Serum glucoseSerum glucose Blood pressureBlood pressure
Areas for further study:Areas for further study: Long-term outcomesLong-term outcomes Ethnic groupsEthnic groups ExerciseExercise Intention to treat analysesIntention to treat analyses
What about longer studies?What about longer studies?
6 month and 12 month outcome studies6 month and 12 month outcome studies EvaluatingEvaluating
Weight lossWeight loss Diabetes outcomesDiabetes outcomes Cholesterol valuesCholesterol values
Low carb vs Conventional Diet:
One year outcome
Low carb vs Conventional Diet:
One year outcome Philadelphia VA outpatient practicePhiladelphia VA outpatient practice BMI > 35 kg/m2BMI > 35 kg/m2 N = 132N = 132 All: weekly then monthly counselingAll: weekly then monthly counseling Randomized: Low carbohydrate or Low Randomized: Low carbohydrate or Low
fatfat
Stern, L. et. al. Ann Intern Med 2004;140:778-785
Study subjectsStudy subjects
60% African American60% African American 80% Male80% Male 40% diabetic40% diabetic 50% hyperlipidemic50% hyperlipidemic 60% hypertensive60% hypertensive
Are the results likely to be valid?
Are the results likely to be valid?
Patients randomized and similarPatients randomized and similar Follow-up long and complete??Follow-up long and complete??
1 year study1 year study Continued in entire study 66%Continued in entire study 66% Final weight: 96%Final weight: 96%
Patients analyzed in their groupPatients analyzed in their group Patients not blind; Researchers??Patients not blind; Researchers?? Groups treated equallyGroups treated equally
Stern, L. et. al. Ann Intern Med 2004;140:778-785
Dietary resultsDietary results
BaselineBaseline 1 Year1 Year
CALORIESCALORIES Not sigNot sig
Low calorieLow calorie 19191919 18221822
Low carbLow carb 19721972 14621462
CARBSCARBS p = 0.01p = 0.01
Low calorieLow calorie 252252 230230
Low carbLow carb 251251 120120
Blood test resultsBlood test resultsBaselineBaseline 1 year1 year
TGsTGs p = 0.041p = 0.041
Low calLow cal 162162 166166
Low carbLow carb 201201 144144
HDLHDL p = 0.014p = 0.014
Low calLow cal 4141 3636
Low carbLow carb 4141 4040
HgbA1cHgbA1c Not sigNot sig
Low calLow cal 7.37.3 7.27.2
Low carbLow carb 7.4 7.4 6.66.6
ConclusionsConclusions
Needed 284 persons to show a Needed 284 persons to show a differencedifference
Is the low carb diet less sustainable?Is the low carb diet less sustainable? What are the long term outcomes?What are the long term outcomes?
A second Study:One year outcomeA second Study:
One year outcome
N = 63N = 63 68% female68% female Excluded patients with diabetesExcluded patients with diabetes Randomized to Atkins or low fatRandomized to Atkins or low fat
60% carbs, 25% fat, 15% protein60% carbs, 25% fat, 15% protein No counseling sessionsNo counseling sessions
Foster, et al. NEJM 2003;348:2082-90
A second Study:One year outcomeA second Study:
One year outcome 37 subjects completed the study37 subjects completed the study HDL increased significantlyHDL increased significantly
P = 0.04P = 0.04 11% change11% change
TGs decreased significantlyTGs decreased significantly P = 0.04P = 0.04 17% change17% change
Diastolic BP and insulin sensitivity better in Diastolic BP and insulin sensitivity better in both groupsboth groups
Foster, et al. NEJM 2003;348:2082-90
ConclusionsConclusions
Similar findings to other weight loss Similar findings to other weight loss treatmentstreatments
High attritionHigh attrition How safe is it?How safe is it?
DateDate WeightWeight HgbA1cHgbA1c TxTx
11/13/0311/13/03 248248 7.9%7.9% Zone dietZone diet
2/09/042/09/04 231231 6.9%6.9%
5/20/045/20/04 235235 6.6%6.6%
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