Calorie Counting Vs. Time-Restricted Eating: Which Is Better for Weight Management?

A new study suggests that when it comes to weight loss, how many calories you consume may matter more than when you eat.

Specifically, researchers found that people who followed a time-restricted diet lost the same amount of weight as those who ate the same diet without the time restriction.

The findings, published in the Annals of Internal Medicine, challenge the efficacy of intermittent fasting, or time-restricted eating (TRE), a popular weight loss method that narrows eating times to specific windows. Proponents tout the strategy as an easier way to lose weight than old-fashioned calorie counting.

While previous research has linked time-restricted eating with weight loss, the mechanism behind the strategy’s success has remained unclear. The team behind the new study wanted to examine whether time-restricting eating can induce weight loss independent of the amount of calories a person consumes. 

The authors concluded that it didn’t, suggesting that “any effects of TRE on weight in prior studies may be due to reductions in caloric intake” in light of the shorter eating window.

A Closer Look at the Study’s Findings

The scientists recruited 41 adults, most of them Black women, with obesity and prediabetes. They supplied them with meals for two weeks based on their individual needs.

Half of the participants were instructed to eat all of their food within a 10-hour window, with 80% of calories consumed before 1 p.m. The other group followed a more traditional eating plan: They ate over 16 hours and consumed at least half their calories after 5 p.m.

Participants in both groups consumed the same daily calories, and the meals had similar nutritional composition.

After three months, the scientists discovered that participants in both groups lost about the same amount of weight. People in the time-restricted group lost 5 pounds, while those in the other group lost 5.7 pounds. Both groups experienced similar changes in blood sugar and heart health measures, such as blood lipid levels.

“This reinforces the importance of sticking to a calorie-restricted diet when trying to lose weight,” Vanessa Imus, MS, RDN, registered dietitian and weight loss expert in Bothell, Washington, told Health. “Whether you want to track calories or limit your eating window, they are equally effective as long as it is helping to lower your overall calorie intake.” 

Imus added that this data “challenges some of the previous research on meal timing, which concluded that eating more calories earlier in the day was always better for weight loss compared to eating more calories later in the day.”

Weaknesses in the Research

While study author Nisa M. Maruthur, MD, an associate professor of medicine at Johns Hopkins University, noted that “there is good reason to draw strong conclusions from [the] results,” she acknowledged that the study included a small sample size.

Additionally, most participants were Black women, meaning the results may not apply to other groups.

Researchers also provided participants with prepared meals, which “may be very different from how someone might normally eat when put on a time-restricted eating pattern or a calorie-deficit diet,” Imus explained.

What to Consider Before Implementing a Weight Loss Strategy

Before beginning a new weight loss plan, it’s best to consult a healthcare provider to develop a strategy that balances weight loss with health.

If you’re considering cutting calories, for example, a medical professional can help calculate how many calories you need depending on your unique circumstances, such as your size and physical activity levels. That way, you won’t be in danger of consuming too few calories, which can make you feel weak and, over time, lead to health issues like lower immune function and a higher risk of developing chronic diseases.

You also want to consider your lifestyle and interests when choosing a weight-loss method.

Even though the study suggests calories matter more than timing, that doesn’t mean time-restricted eating isn’t the right plan for you. Anyone struggling with erratic eating patterns or seeking a clear, manageable framework for their diet might find the strategy particularly useful.

“It goes back to the idea that the best diet is the one you can stick to,” Maruthur said.

And keep in mind that calorie counting and time-restricted eating aren’t the only tools for shedding weight. Other ways to stay slim include eating more fiber-rich foods, exercising more, limiting processed and sugary foods, and getting adequate sleep.