A lower-carbohydrate, higher-fat diet reduces abdominal and intermuscular fat and increases insulin sensitivity in adults at risk of type 2 diabetes

J Nutr. 2015 Jan;145(1):177S-83S. doi: 10.3945/jn.114.195065. Epub 2014 Dec 3.

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).

Conclusion: 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.

Keywords: PCOS; body composition; glycemic load; insulin secretion; insulin sensitivity; visceral fat.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Abdominal Fat / physiopathology*
  • Adult
  • Biomarkers / blood
  • Blood Glucose / analysis
  • Body Composition
  • Body Weight
  • Cross-Over Studies
  • Diabetes Mellitus, Type 2*
  • Diet, Fat-Restricted*
  • Diet, High-Fat*
  • Energy Intake
  • Fasting
  • Female
  • Food Handling
  • Humans
  • Inflammation / blood
  • Insulin / blood
  • Insulin Resistance*
  • Islets of Langerhans / physiopathology
  • Male
  • Middle Aged
  • Obesity / complications
  • Obesity / physiopathology*
  • Overweight / complications
  • Overweight / physiopathology
  • Polycystic Ovary Syndrome / diet therapy
  • Risk Factors

Substances

  • Biomarkers
  • Blood Glucose
  • Insulin

Associated data

  • ClinicalTrials.gov/NCT00726908
  • ClinicalTrials.gov/NCT01028989