Alternate-Day Fasting: You’ll Never Believe This Discovery

Americans spend billions each year in the next-best quest to lose weight. We try everything from low-fat programs to low-carb diets — and hope it works.

The hot diet trend these days seems to be fasting — in its various forms. While many people have found success using this method of weight loss, a new study now proves it might not be the best way to go.

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The study, published May 1 in the journal JAMA Internal Medicine, looked at whether alternate-day fasting was more effective for weight loss and weight maintenance compared with daily calorie restriction. The randomized clinical trial — which is the longest and largest trial of alternate-day fasting to date — followed 100 metabolically healthy obese adults for a year. They were placed into three groups: an alternate-day fasting group, a calorie-restriction group, and a no-intervention control group.

So what happened? A team of researchers from the University of Illinois at Chicago tracked the participants for a six-month weight-loss phase, followed by a six-month weight-maintenance phase. Those in the alternate-fasting group consumed 25 percent of their typical calorie intake (about 500 calories) on fasting days, and 125 percent of their typical intake on non-fasting days. The calorie-restriction group (on a traditional diet) consumed 75 percent of their typical caloric intake every day.

After collecting a massive amount of data, the authors determined that alternate-day fasting diet was not superior to the daily calorie-restriction diet with regard to adherence, weight loss, weight maintenance, or improvement in risk indicators for cardiovascular disease.

At first I thought: Yes! This is the diet that’s going to work for me.

How were the groups the same? Both groups did drop weight, with a 6 percent loss for the alternate-day fasting group and a 5.3 percent loss for the daily calorie-restriction group. As far as regaining the weight, the researchers determined there was not a significant difference between the two groups (of people) from months six to 12.

Where did the groups differ? “Alternate-day fasting has been promoted as a potentially superior alternative to daily calorie restriction under the assumption that it is easier to restrict calories every other day,” the researchers reported in the write-up in JAMA.

What they found instead was that the dropout rate in the alternate-day fasting group (38 percent) was higher than that of the daily calorie-restriction group (29 percent). More participants in the alternate-day fasting group also withdrew due to dissatisfaction with diet, compared with those in the daily calorie-restriction group.

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The authors concluded that “taken together, these findings suggest that alternate-day fasting may be less sustainable in the long term, compared with daily calorie restriction, for most obese individuals.”

So what’s the best diet for you? When I tried alternate-day fasting myself a few years ago, my initial reaction was: Yes, this is finally the one that’s going to work. And while I experienced some weight loss in a short amount of time, the longevity of the program was not for me.

After a few weeks of eating one day and not the next, I quit and gained the weight back rather quickly.

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What I discovered — and what most experts can agree on — is that the best diet for you is the one you are most likely to stick with over time.

Whether you choose to practice intermittent fasting or eat every day (all hours of the day), there are a few simple tips that most people can follow to help with weight loss and maintenance for life:

1.) Build your diet around lean proteins, fruits, vegetables, healthy fats, and complex carbohydrates.

2.) Minimize processed food and excess sugars.

3.) Exercise at least five times a week for 30-60 minutes per session (including weight training and cardiovascular exercise).

4.) Get enough sleep — aim for seven to nine hours a night.

5.) Minimize or eliminate alcohol and other calorie-containing drinks.

Sara Hermanson is a freelance writer in Washington State whose focus is health, wellness, fitness and parenting.