Is intermittent fasting or restricting calories better for weight loss? New study offers answer

When it comes to weight loss, the timing of food consumption is far less important than the amount of food consumed, the authors of a new study suggest.

After analyzing data on the eating habits of nearly 550 adults from three health systems in Maryland and Pennsylvania, the researchers concluded that timing of food consumption has little impact on weight gain or loss, while the main driver of weight gain is the amount of food people eat, according to the report published in the Journal of the American Heart Association.

“We were most interested in weight gain prevention,” study co-author Dr. Wendy Bennett, associate professor of medicine at Johns Hopkins School of Medicine, tells TODAY.com. “Over time, people tend to gain about one pound per year. So our question was: If you change your eating patterns a little bit, can you prevent weight gain creep?”

Bennett notes that none of the people in the study said they were dieting or were participating in a time restricted eating pattern —commonly known as intermittent fasting. “These aren’t people who were told when they should eat,” she said. “These are free-living patients from three health systems.”

To take a closer look at how people’s eating patterns might impact weight gain, Bennett and her colleagues recruited 547 people who were willing to document on a specialized app what they ate during the day, when they slept, how long after waking they consumed their first meal and how many hours elapsed between their last meal and going to sleep.

Overall, most of the volunteers (80%) in the study were white, with 12% identifying as Black and 3% identifying as Asian. The average age of the participants was 51, and most had a college education or higher. The average body mass index (BMI) was 30.8, which is considered obese.

The researchers obtained background health information on the volunteers through their electronic health records. The volunteers completed an online survey at the start of the study and after four months. The surveys asked about weight, race, sex, education, income, smoking status, weight intentions and behavioral factors.

In the app, volunteers reported approximate meal timing and approximate sizes, which they estimated by looking at an illustration that showed small (a slice of pizza at 500 calories), medium (half a pizza at 500 to 1,000 calories) and large (a whole pizza at more than 1,000 calories).

On average, the time between the volunteers’ first meal and last was 11.5 hours, and the researchers reported that this timing was not associated with weight change. The average amount of time between waking and breakfast was 1.6 hours; the average amount of time between dinner and going to sleep was 4.0 hours; and the average amount of time sleeping was 7.5 hours.

Bennett her colleagues wrote that they “found an association between the eating of more frequent and larger meals per day and weight increase, indicating that total overall caloric intake is the major driver of weight gain.” They added that their findings “did not support the use of time-restricted eating as a strategy for long-term weight loss in a general medical population.”

But Dr. Holly Lofton, director of the NYU Langone Weight Management Program, who wasn’t involved in the study, tells TODAY.com that the researchers didn’t present enough data to back up this conclusion. That said, she agrees the main message from this study is that the high caloric intake is the driver of weight gain.

Dr. Anu Lala, a cardiologist at Mount Sinai Health, also tells TODAY.com that she questions whether the study allowed for directly comparing one method of weight loss to another.

She adds: “The goal should be to pursue a heart healthy lifestyle, which depends on the types of foods we eat and how frequently we eat them in addition to physical exercise. Exercise is not captured here.”

This article was originally published on TODAY.com

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