Recent diet trends have promised that watches are just as important as scales for weight loss. Such a diet is known as intermittent fasting, which involves a schedule of alternating fasting and eating. A popular intermittent fasting plan is time-restricted eating. By restricting eating to a limited number of hours per day, some proponents of this diet argue that people can use their body’s natural rhythms to shed pounds.
But according to new research, most recently a study published in the Journal of the American Heart Association On January 18th, the time you eat doesn’t seem to be helpful for weight loss in and of itself.
In the study, 547 participants used a phone application to track their daily meals over a six-month period, which the researchers used to average what times each person ate each day. how many meals they ate; whether participants labeled each meal as small, medium, or large; and how much weight they gained or lost. Ultimately, they found that the time between the participants’ first and last meal and when they ate relative to the time they woke up or went to sleep did not affect weight. The decisive factor was the size of the participants’ meals: those who ate large or medium-sized meals tended to gain weight, those who ate small meals tended to lose weight.
The co-author of the study, Dr. Wendy Bennett, a family doctor and associate professor at the Johns Hopkins School of Medicine, stressed that this wasn’t the final word on eating timing, partly because it was an observational study — meaning the researchers didn’t control the conditions , while they take place, such as B. the calories they have burned. Krista Varady, a nutrition researcher who studied intermittent fasting at the University of Illinois, Chicago, and did not participate in the study, says there are several factors that can cloud the results, including the small sample size and the dependence of participants, describing the size of their meals as large or small — and not logging specific calorie counts — and using different scales to weigh participants in doctors’ offices.
Despite this, Varady agrees that food doesn’t seem to have magic at any given time. But that doesn’t mean it’s a completely useless concept. Restricting eating to certain times can help people lose weight, Varady says, as long as it causes you to eat less. And for some, she notes, it can be easier to stick to than other diets that require you to count calories. For example, she says, previous research shows that it can help if you only eat within a six to eight hour window — say, 10 a.m. to 4 p.m. (six hours) or 9 a.m. to 5 p.m. (eight hours).
dr Nisa Maruthur, an associate professor at the Johns Hopkins School of Medicine, agrees. “If you have the same calories regardless of when you eat them, it doesn’t affect the weight,” says Maruthur. However, it can be helpful to set time limits. “If you decide that you only eat between 10 a.m. and 4 p.m., the fact is that you may be consuming fewer calories just because you’re just fit [in] so many [meals] During this time.” Maruthur, who did not participate in this particular study but is involved in a broader initiative at Johns Hopkins to study meal timing, says that while eating at a specific time isn’t beneficial, she but would still recommend timed eating if it helps a particular person eat healthier.”The best diet for anyone is probably the diet they can follow,” she says. “If some people find it easier to eat healthier foods because they plan a bit more,” she says, a time-restricted diet might be beneficial.
More must-reads from TIME