Body composition, energy utilization, and nitrogen metabolism with a 4.25-MJ/d low-energy diet supplemented with...

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. Energy deficit was calculated from resting metabolic rates. Subjects fed pyruvate showed a greater weight loss (PY = 5.9 +/- 0.7 kg, placebo = 4.3 +/- 0.3 kg, P less than 0.05), fat loss (PY = 4.0 +/- 0.5 kg, placebo = 2.7 +/- 0.2 kg, P less than 0.05), kg wt loss/4.25-MJ deficit (PY = 0.22 +/- 0.01 kg, placebo = 0.17 +/- 0.01 kg, P less than 0.05, and kg fat loss/4.25-MJ deficit (PY = 0.15 +/- 0.01 kg, placebo = 0.11 +/- 0.01 kg, P less than 0.05). 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.