title: A lower-carbohydrate, higher-fat diet reduces abdominal and intermuscular fat and increases insulin sensitivity in adults at risk of type 2 diabetes.
abstract: BACKGROUND
  Obesity, particularly visceral and ectopic adiposity, increases the risk of type 2 diabetes.
  
  
  OBJECTIVE
  The aim of this study was to determine if restriction of dietary carbohydrate is beneficial for body composition and metabolic health.
  
  
  METHODS
  Two studies were conducted. In the first, 69 overweight/obese men and women, 53% of whom were European American (EA) and 47% of whom were African American (AA), were provided with 1 of 2 diets (lower-fat diet: 55%, 18%, and 27% of energy from carbohydrate, protein, and fat, respectively; lower-carbohydrate diet: 43%, 18%, and 39%, respectively) for 8 wk at a eucaloric level and 8 wk at a hypocaloric level. In the second study, 30 women with polycystic ovary syndrome (PCOS) were provided with 2 diets (lower-fat diet: 55%, 18%, and 27% of energy from carbohydrate, protein, and fat, respectively; lower-carbohydrate diet: 41%, 19%, and 40%, respectively) at a eucaloric level for 8 wk in a random-order crossover design.
  
  
  RESULTS
  As previously reported, among overweight/obese adults, after the eucaloric phase, participants who consumed the lower-carbohydrate vs. the lower-fat diet lost more intra-abdominal adipose tissue (IAAT) (11 ± 3% vs. 1 ± 3%; P < 0.05). After weight loss, participants who consumed the lower-carbohydrate diet had 4.4% less total fat mass. Original to this report, across the entire 16-wk study, AAs lost more fat mass with a lower-carbohydrate diet (6.2 vs. 2.9 kg; P < 0.01), whereas EAs showed no difference between diets. As previously reported, among women with PCOS, the lower-carbohydrate arm showed decreased fasting insulin (-2.8 μIU/mL; P < 0.001) and fasting glucose (-4.7 mg/dL; P < 0.01) and increased insulin sensitivity (1.06 arbitrary units; P < 0.05) and "dynamic" β-cell response (96.1 · 10(9); P < 0.001). In the lower-carbohydrate arm, women lost both IAAT (-4.8 cm(2); P < 0.01) and intermuscular fat (-1.2 cm(2); P < 0.01). In the lower-fat arm, women lost lean mass (-0.6 kg; P < 0.05). Original to this report, after the lower-carbohydrate arm, the change in IAAT was positively associated with the change in tumor necrosis factor α (P < 0.05).
  
  
  CONCLUSIONS
  A modest reduction in dietary carbohydrate has beneficial effects on body composition, fat distribution, and glucose metabolism. This trial was registered at clinicaltrials.gov as NCT00726908 and NCT01028989.
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL bgower@uab.edu.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Gower
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Goss
mesh_terms: D050153:Abdominal Fat / Q000503:physiopathology*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D001835:Body Weight; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2; D018752:Diet, Fat-Restricted; D059305:Diet, High-Fat; D002149:Energy Intake; D005215:Fasting; D005260:Female; D005511:Food Handling; D006801:Humans; D007249:Inflammation / Q000097:blood; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D007515:Islets of Langerhans / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D050177:Overweight / Q000150:complications / Q000503:physiopathology; D011085:Polycystic Ovary Syndrome / Q000178:diet therapy; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin
keywords: PCOS; body composition; glycemic load; insulin secretion; insulin sensitivity; visceral fat