Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials

J Transl Med. 2018 Dec 24;16(1):371. doi: 10.1186/s12967-018-1748-4.


Background: This systematic review and meta-analysis summarized the most recent evidence on the efficacy of intermittent energy restriction (IER) versus continuous energy restriction on weight-loss, body composition, blood pressure and other cardiometabolic risk factors.

Methods: Randomized controlled trials were systematically searched from MEDLINE, Cochrane Library, TRIP databases, EMBASE and CINAHL until May 2018. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI).

Results: Eleven trials were included (duration range 8-24 weeks). All selected intermittent regimens provided ≤ 25% of daily energy needs on "fast" days but differed for type of regimen (5:2 or other regimens) and/or dietary instructions given on the "feed" days (ad libitum energy versus balanced energy consumption). The intermittent approach determined a comparable weight-loss (WMD: - 0.61 kg; 95% CI - 1.70 to 0.47; p = 0.87) or percent weight loss (WMD: - 0.38%, - 1.16 to 0.40; p = 0.34) when compared to the continuous approach. A slight reduction in fasting insulin concentrations was evident with IER regimens (WMD = - 0.89 µU/mL; - 1.56 to - 0.22; p = 0.009), but the clinical relevance of this result is uncertain. No between-arms differences in the other variables were found.

Conclusions: Both intermittent and continuous energy restriction achieved a comparable effect in promoting weight-loss and metabolic improvements. Long-term trials are needed to draw definitive conclusions.

Keywords: Continuous energy restriction; Fasting glucose; Intermittent energy restriction; Triglycerides; Weight loss.

Publication types

  • Comparative Study
  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Adult
  • Aged
  • Biomarkers / metabolism
  • Caloric Restriction*
  • Female
  • Heart / physiology*
  • Humans
  • Male
  • Metabolism*
  • Middle Aged
  • Publication Bias
  • Randomized Controlled Trials as Topic*
  • Weight Loss*


  • Biomarkers