DIET AND EXERCISE STRATEGIES FOR WEIGHT LOSS AND WEIGHT MAINTENANCE

Transcription

1 DIET AND EXERCISE STRATEGIES FOR WEIGHT LOSS AND WEIGHT MAINTENANCE 40 yo woman, BMI 36. Motivated to begin diet therapy. Which of the following is contraindicated: Robert B. Baron MD MS Professor and Associate Dean UCSF School of Medicine Declaration of full disclosure: No conflict of interest 1. Meal replacement, very low calorie diet 2 Atkins diet 3 Ornish diet 4. Zone diet 5. All are contraindicated 6. None are contraindicated COMPARISON OF ATKINS, ORNISH, WEIGHT WATCHERS, AND ZONE 160 patients, randomly assigned Intention to treat at 1 year Atkins Ornish WW Zone Wt Loss (kg) Completers (%) Completers at 1 year Atkins Ornish WW Zone Wt Loss (kg) COMPARISON OF ATKINS, ORNISH, WEIGHT WATCHERS, AND ZONE Weight loss associated with adherence, but not diet type Each group: 25% lost 5%, 10% lost 10% of initial weight Each diet reduced LDL/HDL by 10% No significant effects on BP or glucose CRP and insulin reductions associated with weight loss, but not diet Dansinger, JAMA 2005 Dansinger, JAMA,

2 META ANALYSIS OF LOW CARB STUDIES 5 studies, 447 subjects 6 months 12 months Favors low-carb Wt Loss (kg) -3.3* -1.0 Yes LDL-C (mg/dl) 8.9* 10.1* No HDL-C (mg/dl) 4.6* 3.1 Yes Triglycerides mg/dl -22.1* -31.0* Yes SBP (mm Hg) Yes DBP (mm Hg) Yes Yellow = favors low carb * p < 0.5 Nordmann, Arch Int Med 2006 COMPARISON OF ATKINS, ZONE, ORNISH, AND LEARN 311 patients, randomly assigned Intention to treat at 1 year Atkins Zone LEARN Ornish Wt Loss (kg) 4.7 * LDL-C (mg/dl) HDL-C (mg/dl) 4.9* Glucose (mg/dl) SBP (mm Hg) -7.6* DBP (mm Hg) -4.4* * p < 0.5 Gardner, JAMA 2007 Heterogeneity of Response to Weight Loss Diets: Insulin Resistance Insulin sensitive: low carb and high carb both effective for weight loss Insulin resistant: low carb more effective COMPARISON OF DIETS WITH DIFFERENT MACRONUTRIENTS RCT of 811 patients, 4 diets: fat/protein/carbs 20/15/65; 20/25/55; 40/15/45; 40/25/35 6 months: 6kg, 7% weight; at 2 years: completers lost 4kg; 15% lost 10% of weight Results similar for: 15% pro v. 25% pro 20% fat v. 40% fat 35% carbs v. 65% carbs Attendance highly correlated with weight loss; satiety, hunger, attendance, lipids, insulin all equal Sacks, NEJM,

3 Which Diet Works Best? Low-fat, Low-carb or Mediterranean 322 moderately obese subjects (40-65 y) randomized to 1 of 3 diets for 2 years Low-carb (Atkins) - no calorie restriction Low fat cal/day Mediterranean cal/day Workplace-based study in Israel Self-service cafeteria with labeled food Many resources (18 dietician sessions) High adherence: 95% at 1 y; 85% at 2 y Shai et al. NEJM 2008 Which Diet Works Best? Low-fat, Low-carb or Mediterranean Greatest weight lost with lowcarb and Mediterranean Greatest reduction in lipids with low-carb Best glycemic control with Mediterranean Shai I et al. NEJM 2008;359: yo woman, BMI 36. Motivated to begin diet therapy. Which of the following is contraindicated: 1. Meal replacement, very low calorie diet 2 Atkins diet 3 Ornish diet 4. Zone diet 5. All are contraindicated 6. None are contraindicated 3

4 VLCD s vs LCD s: Meta-analysis of 6 RCTs Trials with direct comparisons Short-term: mean 12.7 weeks Long-term: mean 1.9 years Weight loss (as % of initial weight): short-term long-term LCDs VLCDs (p) (0.001) (0.2) 40 yo woman, BMI 33. Which abnormality best predicts her 10 year mortality? 1. Waist circumference: 36 inches 2 Fasting blood sugar: 110 mg/dl 3 Systolic BP: 140 mm Hg 4. Triglycerides: 185 mg/dl 5. Exercise test: early stage 2 (fatigue) Tsai and Wadden, Obesity, 2006 FITNESS AND MORTALITY Aerobics Center Longitudinal Study 25,714 men, 44 years old, 14 year observational study CV death (RR) normal overweight obese Fit Not fit Total death (RR) normal overweight obese Fit Not fit Wei, JAMA 1999 Relative Risk* of Death According to Body Mass and Physical Activity Multivariate relative risk of death Physical activity level > 3.5 hours/week hours/week < 1 hour/week ** < > 30 Body mass index (BMI) * RR s adjusted for age, smoking status, family history, menopausal status, hormone use, and other factors ** Reference group = women with 3.5 or > hours/week of physical activity and BMI of 25 or less Hu FB, et al. N Engl J Med 2004;351:

5 40 yo woman, BMI 33. Which abnormality best predicts 10 year all cause mortality? 1. Waist circumference: 36 inches 2 Fasting blood sugar: Systolic BP: Triglycerides: Exercise test: early stage 2 (fatigue) 60% US adults don t exercise regularly 25% are sedentary Epidemic of Inactivity EXERCISE FOR OBESITY Meta-analysis of 43 RCTs: 3476 participants Exercise vs no Rx small weight losses Exercise plus diet vs diet alone -1.1 kg Increased intensity of exercise -1.5 kg Exercise without weight loss -BP, -TG, -FBS Benefits of Physical Activity Increases cardio-respiratory fitness Decreases risk of chronic diseases Heart disease, high blood pressure, diabetes, some cancers, osteoporosis Promotes psychological well-being Improves functional independence Decreases abdominal fat Improves cognition, dementia Reduces mortality Shaw, Cochrane,

6 40 yo woman, BMI 36. Much to your surprise (and satisfaction), she has lost 35 pounds. In order to maintain her new weight, her lifelong daily calorie intake should be: kcals kcals kcals kcals kcals SUCCESSFUL WEIGHT LOSS MAINTENANCE 3000 subjects in National Weight Control Registry: 30-lb weight loss for 1-year Average weight loss 33 kg (10 BMI units less), average weight maintenance 5.5 years 45 years old, 80% women, 97% Caucasian 46% overweight as child, 46% one parent obese, 27% both parents Wing, Am J Clin Nutr, 2005 SUCCESSFUL WEIGHT LOSS MAINTENANCE High levels of physical activity Women 2545 kcal/week, men 3293 kcal/week (1-hour moderate intensity per day Only 9% report no physical activity Diet low in fat, high in carbohydrate 1381 kcal day, 24% fat, 19% protein, 56% CHO 4.87 meals or snacks/day Fast food 0.74/week Regular self-monitoring of weight 44% weigh once per day; 31% once per week META ANALYSIS OF WEIGHT LOSS MAINTENANCE: 42 RCTs Medications and diet modification (especially after VLCD) Lower fat diets Continued contact Problem-solving therapy Increased caffeine intake Acupressure Wing, Am J Clin Nutr, 2005 Turk, J Cardiovasc Nursing

7 Why It s Hard to Lose/Maintain Weight as We Age We lose 0.33% muscle mass/year starting in our mid-20 s, which results in a 5% decline/decade in resting metabolic rate This reduces # of calories needed to maintain our weight Age 20: 2000 calories/day Age 30: 1900 calories/day Age 40: 1805 calories/day When we lose weight, we need fewer calories Most adults become > sedentary as they age 40 yo woman, BMI 36. Much to your surprise, she has lost 35 pounds. In order to maintain her new weight, her lifelong daily calorie intake should be: kcals kcals kcals kcals kcals Outcomes of Obesity Treatment in Activated Patients Pharmacotherapy: 4-5% Commercial programs (Jenny Craig, Weight Watchers): 5-7% Intensive programs in AMCs: 7-10% Medically supervised programs (Optifast, HMR): 15-25% (but not all sustained) GOALS OF MANAGEMENT Be as fit as possible at current weight Prevent further weight gain If successful at 1 and 2, begin weight loss Surgery: 15% (banding) - 25% (bypass) Tsai, JGIM,

8 The Magic Formula 8