111 DIVERGENT EFFECTS OF WEIGHT LOSS AND MACRONUTRIENT COMPOSITION ON 24-HOUR LIPIDS WITH LOW-CALORIE/LOW-FAT VERSUS LOW-CARBOHYDRATE DIETS. Issue 1 (1st January 2007)

• Record Type: Journal Article
• Authors: Allian-Sauer, M.; Capell, W. H.; Sutherland, J. P.; Wolfe, P.; Talley, N. D.; Hernandez, T. L.; Wyatt, H. R.; Klein, S.; Foster, G.; Hill, J. O.; Eckel, R. H.
• Is Part Of: Journal of investigative medicine. Volume 55:Issue 1(2007)
• Page Start: S95
• Page End: S95
• Publication Date: 2007-01-01
• Subjects: Clinical medicine -- Periodicals; Medicine -- Research -- Periodicals; Medicine; Research -- United States; Clinical medicine; Medicine -- Research; Periodicals; 616.075
• Languages: English
• ISSNs: 1081-5589

Abstract

Abstract : Introduction: Diets with altered macronutrient composition have become a popular method of weight loss. Because a frequent claim made about low-carbohydrate diets relates to the beneficial effects on lipid and lipoprotein metabolism, ie lower triglycerides and higher HDL cholesterol, we sought to assess the impact of low-calorie/low-fat vs low-carbohydrate diets on fasting and 24-hour excursions of triglycerides (TGs) and free fatty acids (FFAs). Methods: Thirty-five subjects were randomized to either a low-calorie/low-fat (LCAL; calorie restricted, < 30% fat, 15% protein and > 55% carbohydrate) or low-carbohydrate (LCARB; < 20 g carbohydrate/day, no limitations on fat or protein intake) diet. Subjects underwent two 24-hour feeding studies on the GCRC at baseline and 6 weeks following randomization. During each feeding study, subjects consumed three standardized meals during which TGs, FFAs, insulin, and glucose were measured hourly. During baseline studies, test meals contained 50% carbohydrates, 35% fat, and 15% protein for all subjects. During the 6- week studies, test meal composition reflected each subject's randomized diet. Results: The average weight loss at 6 weeks was not significantly different by diet (−12.92 ± 7.3 and −14.47 ± 10.6 pounds) for the LCAL and LCARB groups, respectively. Twenty-four-hour TG excursions also did not differ between both groups at 6 weeks. In contrast, 24-hour FFAs were nearly twofold higher in the LCARB group (AUC, 9, 864.3 ± 1711.9 vs 5, 199.6 ± 1, 119.1, p < .0001), associated with persistently low insulin and glucose levels on the low-carbohydrate diet. When comparing baseline with 6 weeks within diet groups, fasting and 24-hour TG were significantly lowered in both the LCAL and LCARB groups, despite the dramatic differences in 24-hour FFA. Conclusion: Our data suggest that the effects of weight loss predominate over dietary macronutrient composition in the overall reduction of TGs. Conversely, the persistently elevated 24-hour FFA levels on the low-carbohydrate diet are likely a direct effect of differing dietary macronutrient compositions. The clinical implications of these divergent effects on lipids have not yet been defined.