Rationale:

• Behavior therapy is one of the cornerstones of therapy for obesity.
• Reduced energy intake is essential for weight loss and is one side of the energy balance equation.
• Increasing physical activity helps increase energy expenditure, the other side of the energy balance.
• Exercise is particularly helpful in maintaining a lower weight.

Evidence:

• School-based programs focusing on nutrition (357), caloric sweetened beverages (357; 358), or increasing water intake (359) were beneficial for weight gain, but physical activity was not (360).
• Behavioral therapy and diet counseling can produce modest weight loss (approximately 5% to 10%) in adults (361), patients with diabetes (362; 363), and children (364; 365; 366). A meta-analysis of 46 trials of dietary counseling found a maximal effect of -1.9 BMI units (6 to 7 kg) at 12 months (367). A randomized trial found that increasing behavioral skills or social facilitation could improve maintenance of weight loss in children (368). Weight loss in black women may be less (369).
• Lifestyle intervention improves the metabolic syndrome (370; 371) and quality of life, as assessed by physical functioning and decreased depression (372), and can be implemented at the community level (373).
• A study found a 32-week personalized Polar weight management program to be superior to standard care (374) and a commercial program (375).
• Portion-controlled or structured meal plans and plates (376) can enhance calorie monitoring (377; 378), and can prevent weight gain induced by the anti-diabetes drug pioglitazone (379).
• Increasing therapist contact between patients and health care providers may enhance weight loss (380), as may use of financial incentives (183). Telephone and Internet use may also help (381; 382; 383; 384; 385; 386) and at little extra cost (387). Motivational interviewing may also improve weight loss (388; 389; 390).
• A seminar for college students on healthy lifestyle slowed weight gain over 2 years (391), and a simple weight loss intervention in adults produced clinically significant weight loss over 32 weeks (392).
• Improving diet pattern reduced weight and improved health more than exercise in the Oslo Diet and Exercise Study (393).
• Calorie reduction with very low calorie diets (289), food provision (394), structured meal plans (378), and eating foods with a low glycemic index (395) that are low fat (396; 397; 398) or vegan diets (399) can be beneficial in weight reduction (378; 395). Evaluating data in children is difficult due to lack of quality studies (400; 401).
• Weight gain during pregnancy can be ameliorated by nutrition counseling (402), and diet plus exercise is more effective than either alone in postpartum women (403).
• Brief clinic-based support can help patients with diabetes lose weight (404). Brief monthly personal contact provided modest benefit in maintaining an initial weight loss (405; 406; 407).
• In six randomized clinical trials, very-low-calorie diets produced greater weight loss and prevented weight gain (408).
• Compared to irregular meal frequency, eating meals regularly lowered food intake, increased thermogenesis, and lowered LDL cholesterol (409). However, a larger trial found no effects of macronutrient composition or weight loss at 6 months or 2 years (410).
• Very-low-carbohydrate (Atkins type) diets were more effective in three short-term trials at 6 months but not 12 months (411; 412; 413). In two head-to-head trials lasting 1 year, the Atkins diet was better in one trial (414) but not in another (415) when compared to the Ornish or Zone diets. In a 2-year trial the low-carbohydrate and Mediterranean diet had a 0.6 to 1.5 kg greater weight loss than the low-fat diet (416).
• A large trial (n=811) randomized obese men and women to 20% vs. 40% fat, 15% vs. 25% protein, and 35%, 45%, 55%, and 65% carbohydrate and found similar weight loss with all diets at 6 and 24 months (410). Diet composition also had no differential effect in preventing weight regain (417).
• Two other 1-year trials found no difference in weight loss between low-carbohydrate and low-fat diets in patients with (418) and without (419) diabetes.
• A meta-analysis of interventions to treat weight gain in schizophrenics showed that cognitive behavior therapy, diet, and exercise were associated with 4.9 kg [CI, 1.7 to 3.3] less gain than diet and exercise alone; behavior therapy produced 2.5 kg [CI, 2.7 to 3.3] less weight gain than placebo (420; 421).
• Family dietary coaching improves nutritional intake in free-living children and parents with beneficial weight control in parents (422).
• A meta-analysis of four studies comparing low glycemic and high glycemic diet favored low glycemic diets in adults (mean weight difference, -1.1 kg [CI, -1.99 to -0.18] (423) and adolescents with obesity (102), but not all studies find this (424; 425; 426).
• Higher protein diets decreased triacylglycerol and increased vitamin B₁₂ levels (427).
• Low-fat diets are effective in weight loss, but the effect is modest (398; 428; 429) and not more than in higher fat diets (430). Adding polyunsaturated n-3 fatty acids to a low-fat diet improved triglycerides and adiponectin (431).
• A DASH-type calorie-reduced diet may be more effective than a regular calorie-reduced diet (432). In a meta-analysis of 43 studies, exercise resulted in small weight loss compared to no treatment; increasing intensity increased weight loss, and exercise lowered diastolic blood pressure, triglycerides, and glucose (433).
• In a randomized trial, adding seafood to an energy-restricted diet enhanced weight loss in men but not women (434) and had no effect on bone turnover (435).
• A meta-analysis of weight loss trials lasting at least 1 year found that reduced energy with or without drugs had a 5% to 9% weight loss at 6 months and 3% to 6% at 48 months. Advise-only and exercise-alone groups had minimal weight loss (436).
• Exercise preserves lean body mass (437) but does not increase loss of visceral fat in women (438); exercise for 30 minutes or more five or more times a week is helpful in weight reduction in adults (439) and children (440); access to home equipment may be helpful (441; 442), but intensity and duration do not influence result (443; 444). A post-hoc analysis shows that 275 minutes per week or more of physical activity are needed to maintain weight loss (445). Weight loss may influence the body weight of an untreated spouse (446). A combination of aerobic and resistance training improves insulin sensitivity and physical function in older adults with central obesity (447).
• Walking assessed with pedometers improved weight loss and health (448; 449).
• Reducing television viewing and computer use may lower BMI in children (450).
• Rewarding physical activity in obese children can enhance weight loss (451; 452) and improve adolescents' psychopathology (453).
• Exercise decreases triglycerides in overweight and obese adults; an increase in HDL cholesterol was associated with an increase in maximum oxygen consumption (454) and a small weight loss (~1.0 kg) (455).
• Strength training over 2 years in pre-menopausal women reduced body fat -3.7% and slowed the rise in visceral fat (456); resistance training conserves fat-free mass and maintains resting energy expenditure following weight loss (457).
• Vigorous exercise may have more cardioprotective effects than moderate-intensity exercise (458; 459), and moderate-to-vigorous exercise for 60 minutes 6 days per week produced more weight loss (-1.4 kg in women; -1.8 kg in men) than in a non-exercise group in over 12 months (460).
• Diet and exercise may improve function in obese people with knee osteoarthritis (461; 462).
• Weight loss may improve asthma (463).
• In a study of 48 adults, calorie-restricted weight loss but not exercise-induced weight loss was associated with decreases in bone mineral density as measured at the hip and lumbar spine (464).
• A meta-analysis of interventions to promote physical activity in children and adolescents found strong evidence that school-based programs with family involvement can increase physical activity (465). Improving fitness in a school setting can reduce body fat (466) and BMI (467). However, there is currently little evidence to support school-based programs to prevent obesity (468).
• Participation in the Weight Watchers program was associated with a 5.3% weight loss at 1 year and 3.2% at 2 years (469).
• Calcium plus vitamin D supplements may slow weight regain (470).

Comments:

• Two large analyses compare strategies for weight loss in children (471).