Intermittent fasting two days versus one day per week, matched for total energy intake and expenditure, increases weight loss in overweight/obese men and women

Nutr J. 2022 Jun 4;21(1):36. doi: 10.1186/s12937-022-00790-0.

Abstract

Background: Intermittent fasting (IF), consisting of either a one-day (IF1) or two consecutive days (IF2) per week, is commonly used for optimal body weight loss. Our laboratory has previously shown an IF1 diet combined with 6d/week of protein pacing (P; 4-5 meals/day evenly spaced, ~ 30% protein/day) significantly enhances weight loss, body composition, and cardiometabolic health in obese men and women. Whether an IF1-P or IF2-P, matched for weekly energy intake (EI) and expenditure (EE), is superior for weight loss, body composition, and cardiometabolic health is unknown.

Methods: This randomized control study directly compared an IF1-P (n = 10) versus an IF2-P (n = 10) diet on weight loss and body composition, cardiovascular (blood pressure and lipids), hormone, and hunger responses in 20 overweight men and women during a 4-week weight loss period. Participants received weekly dietary counseling and monitoring of compliance from a registered dietitian. All outcome variables were assessed pre (week 0) and post (week 5).

Results: Both groups significantly reduced body weight, waist circumference, percent body fat, fat mass, hunger, blood pressure, lipids, glucose, and increased percent fat-free mass (p < 0.05). However, IF2-P resulted in significantly greater reductions in body weight (-29%) and waist circumference (-38%) compared to IF1-P (p < 0.05), and showed a strong tendency for greater reductions in fat mass, glucose, and hunger levels (p < 0.10) despite similar weekly total EI (IF1-P, 9058 ± 692 vs. IF2-P, 8389 ± 438 kcals/week; p = 0.90), EE (~ 300 kcals/day; p = 0.79), and hormone responses (p > 0.10).

Conclusions: These findings support short-term IF1-P and IF2-P to optimize weight loss and improve body composition, cardiometabolic health, and hunger management, with IF2-P providing enhanced benefits in overweight women and men.

Trial registration: This trial was registered March 03, 2020 at www.

Clinicaltrials: gov as NCT04327141 .

Keywords: Fat mass; Fat-free mass; Hunger; Insulin-like growth factor -1 (IGF-1); Intermittent fasting; Protein pacing; Weight loss.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Body Composition
  • Cardiovascular Diseases*
  • Diet, Reducing / methods
  • Energy Intake / physiology
  • Fasting
  • Female
  • Glucose
  • Health Expenditures
  • Hormones
  • Humans
  • Lipids
  • Male
  • Obesity
  • Overweight*
  • Weight Loss / physiology

Substances

  • Hormones
  • Lipids
  • Glucose

Associated data

  • ClinicalTrials.gov/NCT04327141