Reducing total calories more effective than intermittent fasting, study suggests

A recent study found no association between timing from first meal to last meal and weight loss over the course of a six-year trial period.

The study, published in the Journal of the American Heart Association, was by Wendy Bennett, MD, MPH, an associate professor of medicine at John Hopkins University School of Medicine in Baltimore, Maryland. Several studies have explored the impact of time restricted eating, or intermittent fasting, on weight loss, but many have been inconclusive. For this investigation, scientists aimed to better understand the association between time from the first meal to the last meal and weight loss.

To do this, researchers analyzed the health records of nearly 550 adults from three healthcare systems in Maryland and Pennsylvania. In the two years prior to the study’s enrollment, each participant had at least one weight and height measurement registered. Of the participants, 80 percent were white adults, 12 percent were Black adults, and three percent identified as Asian adults. Their average age was 51 years, and their average body mass was 30.8, which is considered obese. The average follow-up time for weight recorded in the electrical health record was 6.8 years.

Researchers measured the time from the first meal to the last meal each day, the time lapse from waking up to first meal, and the interval from the last meal to sleep of each patient using data from a mobile application. In the application, participants cataloged sleeping, eating, and wake up time each day during the first month of the study. For the following six months, participants were asked to use the application one week every month.

Upon analysis, researchers found no association between weight change during the six-year follow-up period in a population with a wide range of body weight. Results showed that the daily number of large meals, an estimated 1,000 calories, and medium meals, estimated at 500 to 1,000 calories, were each associated with increased weight in the six-year follow up. Fewer small meals, however, estimated at less than 500 calories, were associated with decreasing weight.

According to the study’s authors, although the results indicated an association between fewer overall calories and weight loss, a direct link could not be determined. The study’s design, said the authors, had several limitations in that it didn’t evaluate the complex interactions between timing and frequency of eating and was unable to determine the participants’ intentionality of weight loss. Researchers suggested that future studies should focus on the cause and effect of intermittent fasting as well as include a more diverse population.