A Calorie is a Calorie Or is It? 6 th Biennial Childhood Obesity Conference, June 30, 2011

Transcription

1 A Calorie is a Calorie Or is It? 6 th Biennial Childhood Obesity Conference, June 30, 2011 Jeff S. Volek, Ph.D., R.D. Human Performance Laboratory Department of Kinesiology University of Connecticut Storrs, CT

2 Disclosures Grant Support: Glanbia Nutritionals, National Dairy Counsel, Smart Balance, Lonza, Atkins Nutritionals, Egg Nutrition Center Consultant: UCAN Co, Medifast, Atkins Nutritionals Inc

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4 70 Prevalence (%) Overweight BMI Obese BMI

5 The increase in calories during the obesity epidemic was due largely to carbohydrate intake CARBOHYDRATE PROTEIN FAT

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7 1. Adolescents and adults vary in their ability to metabolize carbs 2. Those who can easily manage carbs have more options 3. Those who can t easily manage carbs should be allowed to self-identify themselves as carbohydrate intolerant 4. For those who are carbohydrate intolerant, carbohydrate restriction is a life-style that saves lives

8 Low fat diets match the metabolic fingerprint of less than half the population The majority of people are hardwired to respond favorably to a low carbohydrate intake

9 Insulin Resistance: Reduced ability of peripheral tissues to respond properly to insulin Since the inability to properly metabolize dietary carbohydrate is the direct result when insulin action is impaired IR = Carbohydrate Intolerance

10 Re-examination of the A to Z Study [Gardner et al. JAMA 2007] Women divided into tertiles based on insulin resistance Weight loss at 12 mo: Low Carb Low Fat Simply put, insulin resistance strongly influences how we respond to different diets Insulin Resistant Insulin Sensitive lbs -3.3 lbs lbs -9.0 lbs Gardner, C.D., et al., Insulin Resistance - An Effect Moderator of Weight Loss Success on High vs. Low Carbohydrate Diets. Obesity, : p. S82.

11 Sugar Spike Causes the body to overreact with large amounts of INSULIN Sugar Crash As a result, blood sugar levels dip below normal

12 Maximum Low Carbohydrate Diet Fat Breakdown High Carbohydrate Diet Minimum Low High Insulin Concentration Jenson et al. Diabetes. 38: , 1989

13 Minimal Small to moderate Large

14 >10x

15 Ingest Carbohydrate Fructose Blood Glucose (1-2 teaspoons) Road to Health Road to Metabolic Syndrome Glycogen ( 400 g) Oxidation Glycogen ( 100 g) Lipogenesis (fat synthesis) FAT

16 Features of MetS Weight Fat TG HDL Glu Insulin BP Improved by CHO Restriction Weight Fat TG HDL Glu Insulin BP

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19 Limit your intake of saturated fat to <7% of energy.

20 SFA Intake Plasma LDL Heart Disease? Renowned science writer Gary Taubes What if It s All Been a Big Fat Lie? Good Calories, Bad Calories 2007 Why We Get Fat Carefully referenced articles/books exposing the lack of quality science behind low-fat diets.

21 Diet Heart Hypothesis Metabolic Syndrome

22 Conclusions Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk.

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24 Replacing 5%en of SFA w/ carbs coronary events (HR 1.07) Jakobsen et al. AJCN Feb 11 (Epub)

25 Low Fat Low SFA Low Carbohydrate Diet 12 wk Low Fat Diet ~1500 kcal/day Low Carb Diet ~1500 kcal/day PRO CHO PRO CHO FAT Saturated Fat = 12 g FAT Saturated Fat = 36 g

26 Blood Saturated Fat Levels Low Fat Diet 12 g SFA/d 208 CHO/d Saturated Fat Low Carbohydrate Diet 36 g SFA/d 45 CHO/d Saturated Fat

27 Change Plasma SFA (%wt) in TAG Low Fat Low Carb Change Plasma SFA (mg/dl) in TAG Low Fat Low Carb 0 Despite eating 3 times more SFA compared to low-fat, subjects showed significantly greater reductions in plasma SFA on a low carbohydrate diet Forsythe et al. Lipids. 43(1):65-77, 2008

28 Dietary Matrix SFA CHO Saturated fat has a totally different metabolic behavior when consumed in the context of a low carbohydrate diet. Path Dependence on Ambient CHO Plasma SFA; 16:1 Insulin Sensitivity Normolipidemia Metabolic Health Continuum Plasma SFA; 16:1 Insulin Resistance Dyslipidema

29 or you are what you do with what you eat!

30 The cause of insulin resistance remains unclear, but a wellformulated low carbohydrate diet consistently makes it better Dietary saturated fat is efficiently metabolized in the presence of low carbohydrate The immediate opportunity is to harness these benefits in the management of obesity, metabolic syndrome, and diabetes