Differential Effects of Alternate-Day Fasting Versus Daily Calorie Restriction on Insulin Resistance

Obesity (Silver Spring). 2019 Sep;27(9):1443-1450. doi: 10.1002/oby.22564. Epub 2019 Jul 22.


Objective: This study compared the effects of alternate-day fasting (ADF) with those of daily calorie restriction (CR) on body weight and glucoregulatory factors in adults with overweight or obesity and insulin resistance.

Methods: This secondary analysis examined the data of insulin-resistant individuals (n = 43) who participated in a 12-month study that compared ADF (25% energy needs on "fast days"; 125% energy needs on alternating "feast days") with CR (75% energy needs every day) and a control group regimen.

Results: In insulin-resistant participants, weight loss was not different between ADF (-8% ± 2%) and CR (-6% ± 1%) by month 12, relative to controls (P < 0.0001). Fat mass and BMI decreased (P < 0.05) similarly from ADF and CR. ADF produced greater decreases (P < 0.05) in fasting insulin (-52% ± 9%) and insulin resistance (-53% ± 9%) compared with CR (-14% ± 9%; -17% ± 11%) and the control regimen by month 12. Lean mass, visceral fat mass, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, blood pressure, C-reactive protein, tumor necrosis factor α, and interleukin 6 values remained unchanged.

Conclusions: These findings suggest that ADF may produce greater reductions in fasting insulin and insulin resistance compared with CR in insulin-resistant participants despite similar decreases in body weight.

Trial registration: ClinicalTrials.gov NCT00960505.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Caloric Restriction / methods*
  • Fasting / physiology*
  • Female
  • Humans
  • Insulin / blood*
  • Insulin Resistance / physiology*
  • Male
  • Middle Aged
  • Young Adult


  • Insulin

Associated data

  • ClinicalTrials.gov/NCT00960505