Safety of alternate day fasting and effect on disordered eating behaviors

Nutr J. 2015 May 6;14:44. doi: 10.1186/s12937-015-0029-9.

Abstract

Background: Alternate day fasting (ADF; ad libitum intake "feed day" alternated with 75% restriction "fast day"), is effective for weight loss, but the safety of the diet has been questioned. Accordingly, this study examined occurrences of adverse events and eating disorder symptoms during ADF.

Findings: Obese subjects (n = 59) participated in an 8-week ADF protocol where food was provided on the fast day. Body weight decreased (P < 0.0001) by 4.2 ± 0.3%. Some subjects reported constipation (17%), water retention (2%), dizziness (<20%), and general weakness (<15%). Bad breath doubled from baseline (14%) to post-treatment (29%), though not significantly. Depression and binge eating decreased (P < 0.01) with ADF. Purgative behavior and fear of fatness remained unchanged. ADF helped subjects increase (P < 0.01) restrictive eating and improve (P < 0.01) body image perception.

Conclusions: Therefore, ADF produces minimal adverse outcomes, and has either benign or beneficial effects on eating disorder symptoms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Body Image / psychology
  • Body Mass Index
  • Body Weight / physiology
  • Constipation / epidemiology
  • Constipation / etiology
  • Depression / epidemiology
  • Depression / etiology
  • Diet, Reducing / adverse effects*
  • Diet, Reducing / methods*
  • Dizziness / epidemiology
  • Dizziness / etiology
  • Energy Intake / physiology
  • Fasting / adverse effects*
  • Feeding Behavior / psychology*
  • Feeding and Eating Disorders / epidemiology
  • Feeding and Eating Disorders / etiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Weight Loss*