For this study, researchers recruited 99 participants from Spain with an average age of 49 who were considered to have overweight or obesity.

Study participants were randomly assigned to one of four groups for 12 weeks:

• Habitual eating window of 12 hours or more
• Early time-restricted eating (8-hour eating window that starts before 10:00 am)
• Late time-restricted eating (8-hour eating window that starts after 1:00 pm)
• Self-selected time-restricted eating (8-hour eating window whenever the participant wanted it)

Scientists recorded the body weight and waist and hip circumference of each participant at the start of the study, after 12 weeks, and 12 months after the study’s conclusion.

At the 12-month mark after the study’s conclusion, Camacho-Cardenosa and her team found that participants in the habitual eating group experienced a weight gain, while all three time-restricted eating groups maintained a weight loss.

Those in the habitual eating group also showed an increase in waist circumference after 12 months, while those in all three time-restricted eating groups remained lower.

“The fact that participants were able to maintain weight loss after 12 months shows that time-restricted eating can be a sustainable long-term approach. It means that this strategy does not just help people lose weight, but it can also help them maintain it, which is a major challenge in most weight loss programs.”
— Alba Camacho-Cardenosa, PhD

“Sustaining weight loss over time is one of the biggest challenges in obesity management,” she continued. “Many people lose weight initially but often regain it. Finding new, effective, and pragmatic strategies is crucial to improve long-term health outcomes and reduce the risk of chronic diseases associated with obesity.”

“Our next step is to explore how time-restricted eating combined with exercise affects cardiometabolic health and ectopic fat depots,” Camacho-Cardenosa added. “We also want to identify which types of people benefit most from specific eating windows to further personalize the approach.”

MNT spoke with Mir Ali, MD, a board certified general surgeon, bariatric surgeon, and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, about this study.

Ali said he thought it was a great study that confirmed much of what he has seen in other studies, that there is a benefit to time-restricted eating.

“[W]hat the study showed is that the time of day is not as important as the amount of time you stay away from eating.”
— Mir Ali, MD

“Unfortunately, obesity is a big problem in this country and most Westernized countries, and it’s continuing to rise, and there’s a lot of factors contributing to that. There’s a lot of tools out there available like different types of diet plans, medications, even surgery. But even with all these tools, it can be still difficult to maintain any weight loss. So any kind of help for that is going to be welcome,” Ali said.

For next steps in this research, Ali said it would be helpful if scientists could see which types of diets — such as the Mediterranean or Paleo diets — might be most beneficial with time-restricted eating.

“And further work on what’s the minimum time necessary for the time-restricted eating,” he added. “This one was eight to 12 hours — if we could define that even further it would be helpful.”

For readers considering trying intermittent fasting as a way to both lose weight and maintain weight loss, MNT asked Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, for her top tips.

To start, Richard recommended readers consider their own daily schedule to see how eating times and meeting their own nutritional needs are navigated and may be adjusted.

“Map out what a typical day looks like to take inventory — where breakfast, lunch, dinner, drinks and snacks fit in, and ask if it would work to have those nutritional needs met within an eight-hour window. As well as consider, how will those foods and meals be prepared? What will they consist of? Will that work for me, my family, my current health and needs?”
— Monique Richard, MS, RDN, LDN

“Keeping in mind how the body works is also important,” Richard continued. “We have what is called a migrating motor complex (MMC) — essentially a ‘housekeeper’ of sorts in the form of waves that take place in four different phases. The MMC assists the gut in ‘tidying up’ between meals and supports other digestive and systemic processes. Routines and specific mealtimes do seem to help support these systems to work more optimally and efficiently.”

Richard also encouraged those considering following time-restricted eating to explore the why, how, what, and when of their eating:

• Why are you eating? (i.e. hunger, boredom, access…)
• How are you eating? Are you thoroughly chewing your food? Are you spending time eating your meal (20-40 minutes at a table) or are you gobbling it down in a few large bites in 10 minutes in your car or at your desk?
• What are you eating? Are your meals made up of foods that take effort to chew (i.e. vegetables, salads, whole grains, fruit) or are they easily broken down in your mouth (for example: white breads, chips, biscuits and gravy, greasy breaded items)?
• When are you eating? Every two hours? Once a day? In the middle of the night?

“Time can be on our side, or it can work against us,” Richard added. “When we are intentional with the why, how, what, and when related to our food, aka fuel, we can reap the rewards of our body literally humming along — if you listen closely, you’ll hear it!”