- In a new study, researchers conclude that reducing calories is more important than restricting what time you eat when it comes to losing weight.
- They note that time restrictions can lead to overeating at certain times of the day.
- Experts say there may be some benefits to limiting when you eat, but it’s more important to focus on what foods you are consuming.
Trying to lose weight?
You may get better results by reducing the number of calories you consume rather than restricting when you eat.
That’s according to a new study conducted in China and published in the New England Journal of Medicine.
In the study, 139 participants with obesity were given a calorie-restricted diet. Men were told to consume between 1,500 and 1,800 calories per day. Women were limited to 1,200 to 1,500 calories per day.
Half of the study participants were then told to engage in time-restricted eating, a type of intermittent fasting defined as only eating between certain hours. The participants were permitted to eat their daily calorie allotment only within the hours of 8 a.m. and 4 p.m.
The group using only calorie restrictions lost an average of 14 pounds while the group that was also under time restrictions lost an average of 18 pounds over the 12-month study period.
However, the study authors said they felt the weight loss was not significantly different between the two groups.
In other words, adding intermittent fasting to the weight loss strategy didn’t make a major difference in the outcome.
Nutrition experts say they aren’t convinced this research adds much to the existing conversation on effective weight loss methods.
The study’s findings show that time-restricted eating was not statistically significant to overall daily calorie reduction in body weight loss as well as other secondary outcomes such as changes in waist circumference, body mass index (BMI), body fat, and other metabolic risk factors, said Lon Ben-Asher, MS, RD, LD/N, a nutritionist at Pritikin Longevity Center.
Ben-Asher told Healthline the research confirms what has been well-established: What we eat matters significantly more than when we eat.
“The body needs to get to a negative energy balance by reduction in calorie intake and/or amount of energy expended throughout the day in activities of daily living and exercise,” he explained.
There is some reason why time-restricted eating has become a popular dieting trend in the past decade.
Kristin Kirkpatrick, MS, RDN, a nutritionist and the author of “Skinny Liver,” told Healthline the majority of her clients have found success in time-restricted eating. She explains this approach works because it naturally lowers calories due to time constraints. Her clients often follow a 10 a.m. to 7 p.m. eating schedule.
Beyond weight loss, though, there is some thought that intermittent fasting offers a quick path to improved health. Ben-Asher isn’t convinced we can make any conclusions yet, though.
There’s a lack of studies supporting and demonstrating health benefits beyond weight loss with time-restricted eating in human models, he said.
“Some animal studies have shown an improvement in circadian rhythm by helping to improve metabolic effects such as modulation of blood sugar control and lipid management,” he noted.
So while these animal studies may be promising in showing hormonal balance, improved gut microbiome, and overall body homeostasis, many more studies are needed to determine if it can be demonstrated in humans, said Ben-Asher.
Kirkpatrick says the best diet is one someone can stay on long term, says Kirkpatrick.
She notes that while this study was conducted over the course of a full year, the true level of sustainability occurs after 2 years and beyond.
Ben-Asher suggests following hunger cues rather than setting an eating schedule. Aim your focus on the quality of the food you consume by following your hunger and satiety cues, not the time of the day when you’re “allowed” to eat, he said.
He also recommends paying attention to any disordered eating patterns that may arise if you try intermittent fasting.
“Time-restricted eating can create a disordered eating pattern by the potential of individuals ignoring their hunger cues, simply by the fact that they are more focused on when they can eat versus what they should be eating,” said Ben-Asher.
“This can create a situation where someone is ravenous, which may likely lead to poorer food choices and overindulging and overeating – perhaps affecting an individual’s ability to create a calorie deficit,” he explained.
Ben-Asher added that you should also concentrate your efforts on consuming more foods that create greater satiety per calorie, such as vegetables, fruits, whole grains, unrefined carbohydrates, beans/lentils, and other legumes that contain a high level of dietary fiber and water content.