- Researchers from Johns Hopkins University in Maryland report that time-restricted eating and calorie counting lead to similar weight loss results.
- The study suggests time-restricted eating naturally results in a reduction of about 200 to 550 calories per day.
- Experts say this eating pattern can work well for some people, but the quality and quantity of what you eat still matters most.
The weight loss results of time-restricted eating are nearly identical to traditional calorie counting, according to a study from Johns Hopkins University in Maryland published today in the Annals of Internal Medicine.
Time-restricted eating is a dieting method that defines which hours of the day a person consumes daily calories. Also known as intermittent fasting, popular fasting schedules include 16:8 (fasting for 16 hours, eating in an 8-hour window), or the once-weekly 24-hour fast while following a relaxed eating schedule throughout the rest of the week.
Specific calorie counting is generally not part of time-restricted eating.
Past research and promoters of time-restricted eating have stated this diet pattern improves longevity, encourages weight loss through nutritional ketosis, decreases the risk of various diseases, and improves cognition.
In their randomized controlled trial, researchers looked at 41 adults with obesity and prediabetes.
They randomly assigned the participants to follow a fasting schedule or to count calories. Both groups received identical prepared meals with specific directions on when to eat.
Participants assigned to time-restricted eating followed a 14:10 fasting schedule — fasting for 14 hours and eating between 8 a.m. to 6 p.m. They consumed most of their calories before 1 p.m.
Participants assigned to general calorie counting ate between 8 a.m. and midnight, consuming most of their calories in the evening.
After three months, participants in both groups were assessed for weight loss and changes in fasting glucose levels, waist circumference, blood pressure, and lipid levels.
Researchers concluded that the results between the two groups were essentially the same.
“The findings of the study that the Health benefits of intermittent fasting are solely due to calorie restriction completely supports my own opinion,” Dr. Julie Manasseh, a specialist in obesity medicine at Weight Journey: Medical Weight Loss who was not involved in the study, told Medical News Today.
While she supports intermittent fasting as a method for weight loss, Manasseh says the benefits seen in research are the results of the weight loss itself, not fasting. Other experts agree with her assessment.
“It’s hard to say if I fully agree with the conclusion of this recent study or not,” explained Shetal Desai Rautela, a registered dietitian and owner of Diabetes & Lifestyle Care.
Rautela, who was not involved in the research, suggested using caution before buying into any particular diet or nutrition study.
“As a professional in the field of nutrition, it’s extremely important to keep up with recent research,” Rautela told Medical News Today. “The American Heart Association (AHA) recently published the results of a
Some experts criticized the AHA’s report. In addition, another recent study published in 2023 by the Endocrine Society concluded nearly the opposite — stating that a 16:8 fasting schedule improved glucose levels and cardiometabolic health.
“Overall, what matters is what helps one lose weight safely,” said Rautela, suggesting those considering fasting should have a thoughtful discussion with their healthcare provider first.
“Intermittent fasting can be difficult to keep up with day-in and day-out, both physiologically and practically,” said Rautela.
“Any sort of caloric restriction will always provide initial results for a person trying to lose weight,” said Rautela. “The higher the weight loss goal, the faster the initial weight loss will be on the scale. But is it sustainable?”
“For some people, if any diet feels too forced, restrictive, and difficult to sustain, then it’s likely not worth the effort,” cautioned Rautela, adding that it may still improve your relationship with your body’s natural hunger pangs.
“I always let my clients know that there’s no quick fix for weight loss,” explained Rautela, adding that she often dispels myths about intermittent fasting.
“Intermittent fasting is not just about when you eat,” she explained. “It does still matter how and what you eat. The quality and the quantity of your calories do matter, even if you’re fasting.”
Rautela noted there is big difference in processing the calories from a Big Mac compared to a well-balanded meal comprised of fresh, whole foods.
Manasseh suggested three basic approaches to reducing your calorie intake: consuming low-calorie foods with more fiber, eating smaller portions at meals, and eating less often — which includes intermittent fasting.
“You can use one, two, or all of these methods to achieve calorie restriction,” she said.
Like Rautela, Manasseh cautions against intensely restrictive diets.
“Highly restrictive diets — which have been the mainstay of the diet industry — often involve cutting out whole food groups,” she said. “Diets like 5:2, which involve people having to fast for two whole days a week, are unsustainable long-term.”
Hunger cues and ideal eating patterns also vary from one person to the next.
“I have patients who never eat breakfast because they just don’t feel hungry early in the morning,” explained Manasseh. “For these patients, I advise them to continue not eating breakfast and just have lunch and dinner when they are hungry. These patients are following a fasting schedule, but it suits them because it fits with the pattern of their internal hunger cues.”
“Culturally, we’re constantly surrounded by food,” said Rautela, adding that following a fasting schedule has helped some of her clients re-learn how to recognize genuine hunger cues.
Rautela said she tries to embrace her clients’ enthusiasm for any nutrition or weight loss approach.
“If they’re eager to try something, it shows they care about their health and want to explore it further,” she explained. “My job is to build their knowledge base so they are empowered to make the right and safe decision with support from their healthcare team.”
Like Rautel, Manasseh said mindless eating when you’re not actually hungry is a consistent challenge that fasting can help address.
“Emotional eating and stress eating, or excessive alcohol consumption, are also major factors for the majority of my patients,” said Manasseh. “This needs to be addressed.”
Manasseh and Rautela both expressed the importance of helping each individual develop an approach to nutrition that suits their goals, habits, lifestyle, and personality.
“I start with the patient’s normal diet and help them make improvements to reduce calories while ensuring it’s sustainable long-term,” said Manasseh. “Providing regular support and accountability with progress visits is critical to their success.”
“Over the years, I’ve moved away from a one-size-fits-all approach,” added Rautela. “I’ve seen the most weight loss success with clients when we have frequent check-ins to work through challenges and behaviors while identifying their progress.”
Losing the weight, of course, is only step one. Maintaining it comes next.
“The door never closes when it comes to maintaining your weight loss,” said Rautela. “But that’s a whole different story.”
