Skip to content

Intermittent Fasting Does Work for Weight Loss, Doctor Clarifies

A study suggested the healthy eating plan may not be effective, but further research gives perspective.

There's been a lot of talk about the effectiveness of popular weight-loss plan intermittent fasting. With many studies being done on this time-restricted eating plan, there's also always new information being presented, but the end result is largely the same: intermittent fasting works for weight loss.

Recently, a study was published in JAMA that looked at time-restricted eating and its weight loss effects in both men and women. As the results were shared, some of the information seemed to get misconstrued, according to a doctor who now wants to clarify.

Monique Tello, M.D., MPH, a practicing physician at Massachusetts General Hospital, director of research and academic affairs for the MGH DGM Healthy Lifestyle Program, and clinical instructor at Harvard Medical School, was not involved in the study. But, she recently published a blog post on Harvard Health's blog saying she had seen headlines about this study claiming that intermittent fasting doesn't work and has a significant negative impact on muscle mass. She believes, though, that these research results have largely been misinterpreted. (Related: 5 Science-Backed Benefits of Intermittent Fasting.)

The original study tested 141 overweight patients over a period of 12 weeks. Some were put on a time-restricted eating plan while others followed a traditional eating plan. Dr. Tello points out that there was no true control group in the study because each patient was put on a schedule of some sort. A true control group would have been given no instructions or guidelines.

weight loss
Shutterstock

In the end, both groups lost weight, but the study showed that the intermittent fasting group lost more, including muscle mass that wasn't identified in those on a traditional eating plan. But as Dr. Tello explains in her post, the study makes no mention about the quality of food both groups were eating.

"By the way, all of these folks may have been eating fried or fast foods, and sugary sodas and candy—we don't know," writes Dr. Tello in Harvard Health. "The study doesn't mention quality of diet or physical activity. This isn't how IF is supposed to be done! And yet the IF folks still lost between half a pound and 4 pounds."

Plus, Dr. Tello notes that both groups were given a structured eating plan. Dr. Tello believes having a true control group, in which participants continued to eat as they normally would, could've made these research findings more conclusive.

She reiterated that the study did, in fact, show that intermittent fasting works for weight loss, it's just that some of the results weren't necessarily presented properly, and the study was, perhaps, a bit flawed in its setup.

"While this one negative study adds to the body of literature on IF, it doesn't reverse it," Dr. Tello writes in her post. "We simply need more high-quality studies in order to have a better understanding of how to most effectively incorporate IF into a healthy lifestyle."

To get more weight-loss news delivered straight to your email inbox every day, sign up for our newsletter!

Hedy Phillips
Hedy is a freelance writer with years of experience covering buzzy food trends, wellness, and weight loss. Read more about Hedy