Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During Overeating

Abstract

Context The role of diet composition in response to overeating and energy dissipation in humans is unclear. Objective To evaluate the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition. Design, Setting, and Participants A single-blind, randomized controlled trial of 25 US healthy, weight-stable male and female volunteers, aged 18 to 35 years with a body mass index between 19 and 30. The first participant was admitted to the inpatient metabolic unit in June 2005 and the last in October 2007. Intervention After consuming a weight-stabilizing diet for 13 to 25 days, participants were randomized to diets containing 5% of energy from protein (low protein), 15% (normal protein), or 25% (high protein), which they were overfed during the last 8 weeks of their 10- to 12-week stay in the inpatient metabolic unit. Compared with energy intake during the weight stabilization period, the protein diets provided approximately 40% more energy intake, which corresponds to 954 kcal/d (95% CI, 884–1022 kcal/d). Main Outcome Measures Body composition was measured by dual-energy x-ray absorptiometry biweekly, resting energy expenditure was measured weekly by ventilated hood, and total energy expenditure by doubly labeled water prior to the overeating and weight stabilization periods and at weeks 7 to 8. Results Overeating produced significantly less weight gain in the low protein diet group (3.16 kg; 95% CI, 1.88–4.44 kg) compared with the normal protein diet group (6.05 kg; 95% CI, 4.84–7.26 kg) or the high protein diet group (6.51 kg; 95% CI, 5.23–7.79 kg) (P=.002). Body fat increased similarly in all 3 protein diet groups and represented 50% to more than 90% of the excess stored calories. Resting energy expenditure, total energy expenditure, and body protein did not increase during overfeeding with the low protein diet. In contrast, resting energy expenditure (normal protein diet: 160 kcal/d [95% CI, 102–218 kcal/d]; high protein diet: 227 kcal/d [95% CI, 165–289 kcal/d]) and body protein (lean body mass) (normal protein diet: 2.87 kg [95% CI, 2.11–3.62 kg]; high protein diet: 3.18 kg [95% CI, 2.37–3.98 kg]) increased significantly with the normal and high protein diets. Conclusions Among persons living in a controlled setting, calories alone account for the increase in fat; protein affected energy expenditure and storage of lean body mass, but not body fat storage.

Developing a new treatment paradigm for disease prevention and healthy aging

“…In addition, DASH can be the focus of treatment because recent evidence shows (1) the ready adaptability and enhanced metabolic and CVD risk benefits with DASH plus additional protein [30], (2) modest weight loss through exercise and DASH with reduced energy intake improves insulin sensitivity [31], (3) the association of refined carbohydrates, sugared beverages, and processed foods (i.e., high glycemic load)-and not all higher fat foods-with weight gain, while many foods featured in DASH (e.g., fruits and vegetables, whole grains, nuts) are associated with weight stabilization or loss [32,33], and (4) traditional reduced calorie, lower fat, and higher carbohydrate weight loss diets can result in reduced resting energy expenditure (REE) and total energy expenditure ( TEE), setting the stage for weight regain [7,11]. Studies indicate that the amount of initial weight loss often is not affected by the macronutrient content of the dietary plan, but a higher protein diet may limit weight regain [7,8,11,34,35]. However, the types of foods and meal patterns for DASH are quite PRACTICE AND PUBLIC HEALTH POLICIES different from how most US adults eat [36], raising issues of feasibility and adherence.…”

Effects of weight gain induced by controlled overfeeding on physical activity

“…Findings with respect to overfeeding and physical activity however, are less clear with reports suggesting that physical activity is increased (14), decreased (19) or maintained (7, 24). These discrepant observations could be explained by differences in diet composition which is a plausible explanation since diets varying in protein and fat can have profound effects on many components of daily energy expenditure (5,15,18). Changes in physical activity during the overfeeding of different diets remains largely unknown and has not been tested in a randomized controlled trial.…”

Why Obesity?

“…However, the individuals eating the low-protein diet stored more fat as a percentage of the energy eaten than the other groups. The major effects were thus on changes in various subcompartments of the body such as muscle, liver, and fat (25). During these 45 years, four research themes have emerged in my work.…”