Energetics of Obesity and Weight Control: Does Diet Composition Matter?

Department of Nutritional Sciences, University of Wisconsin-Madison, 53706, USA.
Journal of the American Dietetic Association (Impact Factor: 3.92). 05/2005; 105(5 Suppl 1):S24-8. DOI: 10.1016/j.jada.2005.02.025
Source: PubMed


Greater average weight losses (2.5 kg over 12 weeks) have been reported for low-carbohydrate diets (<90 g/day) compared with traditional low-fat (<25% of energy), hypocaloric diets, implying a 233 kcal/day greater energy deficit. It has therefore been suggested that a low-carbohydrate diet may provide a metabolic advantage (an increase in energy expenditure), resulting in a positive effect on weight loss and maintenance. However, a review of studies in which 24-hour energy expenditure was measured did not provide evidence to support a metabolic advantage of low-carbohydrate diets and showed little evidence of a metabolic advantage of high-protein (>25% of energy) diets. Nonetheless, diets high in protein, but either low or modest in carbohydrate, have resulted in greater weight losses than traditional low-fat diets. We speculate that it is the protein, and not carbohydrate, content that is important in promoting short-term weight loss and that this effect is likely due to increased satiety caused by increased dietary protein. It has been suggested that the increased satiety might help persons to be more compliant with a hypocaloric diet and achieve greater weight loss. The current evidence, combined with the need to meet all nutrient requirements, suggests that hypocaloric weight-loss diets should be moderate in carbohydrate (35% to 50% of energy), moderate in fat (25% to 35% of energy), and protein should contribute 25% to 30% of energy intake. More studies of the efficacy of weight-loss and weight-maintenance diets that address protein content are needed. In addition, controlled studies of total energy expenditure or physical activity measured under free-living conditions that directly compare high-protein diets with those containing low and moderate carbohydrate content should also be performed.

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    ABSTRACT: Background Strategies that may increase compliance to reduced energy intakes are needed to reduce the health burden of obesity. Conflicting evidence exists regarding the effects of snacking on satiety and energy intake. Methods This study compared short-term satiety from two common snack foods, low fat popcorn or potato chips. Using a counterbalanced within-subject design, 35 normal weight non-smoking participants (17 men, 18 women) ages 20–50 years (mean age 33 ± 11, BMI 23 ± 2 kg/m2) consumed four conditions each: 200 mL of water (control), one cup (4 g, 15 kcal) popcorn, 6 cups (27 g, 100 kcal) popcorn, and one cup (28 g, 150 kcal) potato chips, each with 200 mL water. Participants rated their hunger, satisfaction, prospective consumption, and thirst on 100 mm visual analogue scales 30 minutes after commencement of snack consumption. In addition, post-snack energy intake from an ad libitum meal (amount served less amount remaining) was measured, and the test food and meal combined energy intake and energy compensation were calculated. Results Participants expressed less hunger, more satisfaction, and lower estimates of prospective food consumption after six cups of popcorn compared to all other treatments (P < 0.05). Energy compensation was 220% ± 967%, 76% ± 143% and 42% ± 75% after one cup popcorn, six cups popcorn and one cup potato chips, respectively. Combined energy intake was significantly greater (P < 0.01) during the potato chips condition (803 ± 277 kcal) compared to control (716 ± 279 kcal) or popcorn conditions (698 ± 286 kcal for one cup and 739 ± 294 kcal for six cups). Combined energy intakes from both popcorn conditions were not significantly different than control (p > 0.05). Conclusion Popcorn exerted a stronger effect on short-term satiety than did potato chips as measured by subjective ratings and energy intake at a subsequent meal. This, combined with its relatively low calorie load, suggests that whole grain popcorn is a prudent choice for those wanting to reduce feelings of hunger while managing energy intake and ultimately, body weight.
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    • "Protein, carbohydrate, and fat in food stimulate oxygen consumption to different degrees (12), which suggests that dietary composition might affect energy expenditure (13) and thus the rate of weight loss. Mikkelsen et al (14) found that substituting either animal protein (pork) or soy protein for carbohydrate increased energy expenditure by 3% in mildly obese men over 24 hours in a respiration calorimeter. "
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    ABSTRACT: Weight loss reduces energy expenditure, but it is unclear whether dietary macronutrient composition affects this reduction. We hypothesized that energy expenditure might be modulated by macronutrient composition of the diet. The Prevention of Obesity Using Novel Dietary Strategies (POUNDS) LOST study, a prospective, randomized controlled trial in 811 overweight/obese people who were randomized in a 2 × 2 design to diets containing 20en% or 40en% fat and 15en% or 25en% protein (diets with 65%, 55%, 45%, and 35% carbohydrate) provided the data to test this hypothesis. Resting energy expenditure (REE) was measured at baseline, 6, and 24 months using a ventilated hood. REE declined at 6 months by 99.5 ± 8.0 kcal/day in men and 55.2 ± 10.6 kcal/day in women during the first 6 months. This decline was related to the weight loss, and there was no difference between the diets. REE had returned to baseline by 24 months, but body weight was still 60% below baseline. Measured REE at 6 months was significantly lower than the predicted (-18.2 ± 6.7 kcal/day) and was the result of significant reductions from baseline in the low-fat diets (65% or 55% carbohydrate), but not in the high fat diet groups. By 24 months the difference had reversed with measured REE being slightly but significantly higher than predicted (21.8 ± 10.1 kcal/day). In conclusion, we found that REE fell significantly after weight loss but was not related to diet composition. Adaptive thermogenesis was evident at 6 months, but not at 24 months.
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    • "TEF is the energy cost associated with processing of the food for utilization and storage in the body. The composition of food matters: proteins have much higher TEF than fat, and there are some indications that diets high in protein help in regulating weight [14]. AEE includes exercise energy expenditure (EEE) and nonexercise activity thermogenesis (NEAT), which is the energy spent on daily chores, occupational activity, maintaining posture, and fidgeting [15]. "
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