Effects of low-fat compared with high-fat diet on cardiometabolic indicators in people with overweight and obesity without overt metabolic disturbance: a systematic review and meta-analysis of randomised controlled trials

Br J Nutr. 2018 Jan;119(1):96-108. doi: 10.1017/S0007114517002902. Epub 2017 Dec 7.

Abstract

Randomised controlled trials comparing low- v. high-fat diets on cardiometabolic risk factors in people with overweight or obesity have shown inconsistent results, which may be due to the mixed metabolic status of people with excess adiposity. The role of dietary fat manipulation in modifying cardiometabolic indicators in people with overweight or obese without metabolic disturbance is unclear. Thus, meta-analysis was conducted to compare low- v. high-fat diets on cardiometabolic indicators in people who are overweight or obese without metabolic disturbance in the present study. Databases were searched until October 2016. The pooled effects of outcomes with heterogeneity were calculated with a random-effects model, heterogeneities were analysed by subgroup and meta-regression. As a result, twenty studies with 2106 participants were included in the meta-analysis. Total cholesterol and LDL-cholesterol levels were lower following low-fat diets compared with high-fat diets: weighted mean difference (WMD) was -7·05 mg/dl (-0·18 mmol/l; 95 % CI -11·30, -2·80; P=0·001) and -4·41 mg/dl (-0·11 mmol/l; 95 % CI -7·81, -1·00; P=0·011), respectively. Conversely, significant higher level of TAG (WMD: 11·68 mg/dl (0·13 mmol/l), 95 % CI 5·90, 17·45; P<0·001) and lower level of HDL-cholesterol (WMD: -2·57 mg/dl (-0·07 mmol/l); 95 % CI -3·85, -1·28; P<0·001) were found following low-fat diets compared with high-fat diets. In conclusion, dietary fat manipulation has a significant influence on blood lipid levels in people with overweight or obesity without metabolic disturbances.

Keywords: BW body weight; DBP diastolic blood pressure; Hs-CRP high-sensitivity C creative protein; MHO metabolically healthy obese; MUO metabolically unhealthy obese; RCT randomised controlled trial; SBP systolic blood pressure; TC total cholesterol; WMD weighted mean difference; Blood lipids; High-fat diets; Low-fat diets; Metabolically healthy obese.

Publication types

  • Comparative Study
  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Adiposity
  • Body Mass Index
  • Body Weight
  • Cardiovascular Diseases / metabolism*
  • Cholesterol / blood
  • Cholesterol, LDL / blood
  • Diet, Fat-Restricted*
  • Diet, High-Fat*
  • Dietary Fats
  • Female
  • Humans
  • Male
  • Obesity / metabolism*
  • Overweight / metabolism*
  • Phenotype
  • Randomized Controlled Trials as Topic
  • Regression Analysis
  • Sensitivity and Specificity
  • Treatment Outcome

Substances

  • Cholesterol, LDL
  • Dietary Fats
  • Cholesterol