title: A higher-carbohydrate, lower-fat diet reduces fasting glucose concentration and improves β-cell function in individuals with impaired fasting glucose.
abstract: The objective was to examine the effects of diet macronutrient composition on insulin sensitivity, fasting glucose, and β-cell response to glucose. Participants were 42 normal glucose-tolerant (NGT; fasting glucose <100 mg/dL) and 27 impaired fasting glucose (IFG), healthy, overweight/obese (body mass index, 32.5 ± 4.2 kg/m(2)) men and women. For 8 weeks, participants were provided with eucaloric diets, either higher carbohydrate/lower fat (55% carbohydrate, 18% protein, 27% fat) or lower carbohydrate/higher fat (43:18:39). Insulin sensitivity and β-cell response to glucose (basal, dynamic [PhiD], and static) were calculated by mathematical modeling using glucose, insulin, and C-peptide data obtained during a liquid meal tolerance test. After 8 weeks, NGT on the higher-carbohydrate/lower-fat diet had higher insulin sensitivity than NGT on the lower-carbohydrate/higher fat diet; this pattern was not observed among IFG. After 8 weeks, IFG on the higher-carbohydrate/lower-fat diet had lower fasting glucose and higher PhiD than IFG on the lower-carbohydrate/higher-fat diet; this pattern was not observed among NGT. Within IFG, fasting glucose at baseline and the change in fasting glucose over the intervention were inversely associated with baseline PhiD (-0.40, P < .05) and the change in PhiD (-0.42, P < .05), respectively. Eight weeks of a higher-carbohydrate/lower-fat diet resulted in higher insulin sensitivity in healthy, NGT, overweight/obese individuals, and lower fasting glucose and greater glucose-stimulated insulin secretion in individuals with IFG. If confirmed, these results may have an impact on dietary recommendations for overweight individuals with and without IFG.
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA. bgower@uab.edu
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Gower
authors.forename: Laura Lee
authors.initials: LL
authors.lastname: Goree
authors.forename: Paula C
authors.initials: PC
authors.lastname: Chandler-Laney
authors.forename: Amy C
authors.initials: AC
authors.lastname: Ellis
authors.forename: Krista
authors.initials: K
authors.lastname: Casazza
authors.forename: Wesley M
authors.initials: WM
authors.lastname: Granger
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001835:Body Weight / Q000502:physiology; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004041:Dietary Fats / Q000494:pharmacology*; D005215:Fasting / Q000502:physiology*; D005260:Female; D044882:Glucose Metabolism Disorders / Q000097:blood / Q000178:diet therapy*; D005951:Glucose Tolerance Test; D006728:Hormones / Q000097:blood; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000502:physiology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy / Q000503:physiopathology; D050177:Overweight / Q000178:diet therapy / Q000503:physiopathology; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D006728:Hormones