Restricting calories, which is what we normally call dieting, is one of the most common ways people try to lose weight, but it can be extremely difficult to cut back enough on calories on a daily basis to make any headway. Researchers at the University of Illinois may have found a way to make it easier. In a small study published in the November 2009 issue of the American Journal of Clinical Nutrition, the researchers found that partial fasting, every other day, while eating normally on alternate days, helped participants lose up to 30 pounds in eight weeks.
Fasting, which often involves eating no food at all for a short period of time, is an age-old ritual in many religious and spiritual ceremonies. The medical pros and cons of fasting are debated among health experts, however, and little has been done in the way of clinical research to determine what long-term effect, if any, fasting or modified fasting has on weight, health or longevity.
In this study, participants followed a normal diet and exercise routine for two weeks. Once the diet component of the study began, participants ate normal meals on alternate "feeding days," and were restricted to about one-fourth of their normal calorie requirement on fasting days, which they consumed at lunchtime. A key factor in measuring the success of this plan was that, after four weeks in a clinical setting where meals were prepared for them, the dieters were able to stick to the plan on their own for the final four weeks of the study.
The twelve women and four men who participated were between the ages of 35 and 65, and each weighed more than 210 pounds, with a body mass index (BMI) between 30 and 39.9, which indicates clinical obesity. Although the researchers initially estimated that the participants would average about 5 pounds weight loss over the course of the study, they actually lost between 10 and 30 pounds each. In addition, participant's total cholesterol, circulating fat, blood pressure and heart rate dropped by the end of the study.
The next step for researchers is to set up a long-term study, to see if this diet plan is safe, effective, and doable for at least six months, and to determine if partial fasting works as well for weight maintenance as it appears to for weight loss.
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