title: Protein sparing during treatment of obesity: ketogenic versus nonketogenic very low calorie diet.
abstract: Although it is generally agreed that both ketogenic and nonketogenic very low calorie diets promote weight reduction, there is no consensus on a preference of one diet over the other in regard to protein sparing. In the present study, we compared the effects of isocaloric (600 kcal/d) and isonitrogenous (8 g nitrogen/d) ketogenic (low carbohydrate) and nonketogenic diets on parameters of protein and amino acid metabolism, in 16 morbidly obese women maintained on these diets for 4 weeks while confined to a metabolic ward. Cumulative urinary nitrogen excretion (g/4 wk) was significantly (P less than .01) greater (248 +/- 6 v 207 +/- 12, mean +/- SEM, n = 8), and cumulative nitrogen balance significantly (P less than .02) more negative (-50.4 +/- 4.4 v -18.8 +/- 5.7), during treatment with the ketogenic than with the nonketogenic diet. Plasma leucine concentration (mumol/L) was significantly higher (P less than .05) during treatment with the ketogenic than with the nonketogenic diet at day 14 (210 +/- 17 v 150 +/- 8), but not at day 28 (174 +/- 9 v 148 +/- 8). Whole-body rates of leucine oxidation (mmol/h) were significantly higher (P less than .05) during treatment with the ketogenic than with the nonketogenic diet at day 14 (1.29 +/- 0.20 v 0.92 +/- 0.10) and at day 28 (1.00 +/- 0.16 v 0.75 +/- 0.10). Conversely, proteolysis, as measured by leucine turnover rate and urinary excretion of 3-methylhistidine, was not significantly different between the diets.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Montefiore University Hospital, Pittsburgh, PA 15213.
authors.forename: J A
authors.initials: JA
authors.lastname: Vazquez
authors.forename: S A
authors.initials: SA
authors.lastname: Adibi
mesh_terms: D000596:Amino Acids / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism; D015992:Body Mass Index; D003404:Creatinine / Q000652:urine; D004038:Diet, Reducing; D004044:Dietary Proteins; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D007657:Ketone Bodies / Q000378:metabolism; D008762:Methylhistidines / Q000652:urine; D008875:Middle Aged; D009584:Nitrogen; D009767:Obesity, Morbid / Q000178:diet therapy* / Q000378:metabolism / Q000503:physiopathology; D013997:Time Factors; D015431:Weight Loss
chemical_list: D000596:Amino Acids; D001798:Blood Proteins; D004044:Dietary Proteins; D006728:Hormones; D007657:Ketone Bodies; D008762:Methylhistidines; D003404:Creatinine; C028118:3-methylhistidine; D009584:Nitrogen