Does Fish Oil Have an Anti-Obesity Effect in Overweight/Obese Adults? A Meta-Analysis of Randomized Controlled Trials

PLoS One. 2015 Nov 16;10(11):e0142652. doi: 10.1371/journal.pone.0142652. eCollection 2015.


Context: Accumulating evidence has suggested favorable effects of fish oil on weight loss in animal experiments; however, findings remain inconsistent in humans.

Objects: The meta-analysis was performed to investigate the influence of fish oil on some parameters of body composition in overweight/obese adults.

Design: Human randomized, placebo-controlled trials were identified by a systematic search of Embase, PubMed, the Cochrane Library, web of science and reference lists of related reviews and articles. The random-effects model was used to estimate the calculated results.

Results: In total, 21 studies with 30 study arms were included in this analysis. Calculated results of the meta-analysis demonstrated that fish oil had no effect on reducing body weight (overall SMD = -0.07, 95% CI -0.21 to 0.07, P = 0.31) and BMI (overall SMD = -0.09, 95% CI -0.22 to 0.03, P = 0.14) whether alone or combined with life modification intervention in overweight/obese subjects. However, waist circumference was significantly reduced (SMD = -0.23, 95% CI -0.40 to -0.06, P = 0.008) in those with fish oil supplementation combined with life modification intervention. Waist hip ratio (WHR) was significantly reduced (overall SMD = -0.52 95% CI -0.76 to -0.27, P < 0.0005) in fish oil supplemented individuals with or without combination life modification intervention.

Conclusion: Current evidence cannot support an exact anti-obesity role of n-3 polyunsaturated fatty acids (PUFAs) in overweight/obese subjects. However, these subjects may benefit from reducing abdominal fat with fish oil supplementation especially when combined with life modification intervention. Further large-scale and long-term clinical trials are needed to gain definite conclusions.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Obesity Agents / therapeutic use*
  • Body Mass Index
  • Dietary Supplements
  • Fish Oils / therapeutic use*
  • Humans
  • Obesity / drug therapy*
  • Randomized Controlled Trials as Topic
  • Treatment Outcome
  • Weight Loss


  • Anti-Obesity Agents
  • Fish Oils

Grants and funding

This work was supported by a research grant of Shanghai municipal commission of health and family planning, No.20144Y0140, to SD.