The American journal of clinical nutrition
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To determine the effects on weight loss of feeding isonitrogenous diets in mildly restricted (4.2 MJ/d) and severely restricted (2.1 MJ/d) amounts, we measured body composition, weight loss-energy deficit ratio, and nitrogen metabolism in 14 obese women housed in a metabolic ward consuming hypoenergetic diets for 21 d. Subjects consumed either a 4.2-MJ/d diet (50 g protein, 175 g carbohydrate) or a 2.1-MJ/d diet (50 g protein, 75 g carbohydrate). Body composition and leucine oxidation and turnover were determined before and after weight loss. ⋯ Weight loss-energy deficit ratio was the same with both diets. Nitrogen balance and leucine oxidation and turnover were similar in both groups. We conclude that with feeding of isonitrogenous hypoenergetic diets, severe restriction of energy content (2.1 MJ/d, 75 g carbohydrate) will enhance weight and fat loss without increasing nitrogen loss compared with mild restriction of energy (4.2 MJ/d).
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Clinical Trial Controlled Clinical Trial
Body composition, energy utilization, and nitrogen metabolism with a 4.25-MJ/d low-energy diet supplemented with pyruvate.
We measured body composition, energy deficit, and nitrogen metabolism in 14 obese women housed in a metabolic ward, who consumed a 4.25-MJ/d liquid diet (68% carbohydrate, 22% protein) for 21 d with or without pyruvate (PY; n = 7) partially, isoenergetically substituted for glucose (placebo; n = 7). Body composition and leucine oxidation and turnover were determined before and after weight loss. ⋯ Nitrogen balance (urine and stool) and leucine oxidation and turnover were similar in both groups. We conclude that the dietary modification whereby the three-carbon compound pyruvate is isoenergetically substituted for the six-carbon compound glucose in a 4.25-MJ/d, low-energy diet will increase fat and weight loss.