Alternate-day fasting as a diet strategy

Alternate-day fasting as a diet strategy

Researchers at the University of Illinois at Chicago examined the effects of alternate-day fasting under controlled conditions on body weight and coronary artery disease risk in obese adults.

First, the details.

  • 16 obese people completed 10 weeks of a treatment, which consisted of 3 phases.
    • 2-week control phase
    • 4-week weight loss/alternate-day fast controlled food intake phase
    • 4-week weight loss/alternate-day fast self-selected food intake phase
  • The baseline energy requirement was determined for each participant.
  • Participants consumed 25% of their baseline energy needs on the “fast” day and then consumed food ad libitum (at one’s pleasure) on each alternate “feed” day.
  • During this controlled food intake phase, they were provided with a calorie-restricted meal on each fast day, and consumed food ad libitum at home on the alternate day.
  • On the ad libitum food intake day, they were instructed to limit fat intake to 30% of energy needs by choosing low-fat meat and dairy options.

And, the results.

  • The rate of weight loss was about the same during controlled food intake (0.67 kg/week) and self-selected food intake phases (0.68 kg/week).
  • Body weight decreased significantly (5.8%) after 8 weeks of diet.
  • Percentage body fat decreased significantly from 45% to 42%.
  • Total cholesterol, LDL (bad) cholesterol, and triglyceride concentrations were lowered significantly by 21%, 25%, and 32%, respectively, after 8 weeks of alternate day fast; whereas HDL (good) cholesterol was unchanged.
  • Systolic blood pressure decreased significantly from 124 to 116 mm Hg.

The bottom line?

The authors concluded, “These findings suggest that alternate-day fasting is a viable diet option to help obese individuals lose weight and decrease coronary artery disease risk.”

There’s no free lunch. Remember, even on the alternate (non-fasting) day, the participants had to follow a diet protocol.

12/24/10 21:18 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.