Time-Restricted Eating May Not Lead to Weight Loss Without Caloric Reduction, Study Finds

Balancing calorie intake with physical activity is a common prescription for losing weight. However, recent research suggests that the timing of meals could also play a role in weight management. Specifically, the concept of time-restricted eating (TRE) has gained attention, suggesting that limiting the time window for eating each day could help with weight loss and improve metabolic health, potentially offering a new angle in the fight against obesity.

In a study published on 19 April 2024 in the Annals of Internal Medicine, researchers conducted a randomized controlled trial to explore the effects of TRE on body weight and glucose homeostasis, independent of caloric intake. The team, led by Nisa M. Maruthur, MD, MHS, and colleagues from Johns Hopkins University, wanted to understand whether the timing of meals could influence weight loss even when participants consumed a stable amount of calories. You can read the full study here: Annals.org.

The research involved 41 adults with obesity and prediabetes or diet-controlled diabetes. Participants were assigned to two groups with controlled diets of the same nutrient content and calories determined at baseline. One group followed a 10-hour TRE window, consuming 80% of their calories before 1 PM, while the other group had a more standard eating window of up to 16 hours, with most calories consumed after 5 PM. The study lasted 12 weeks.

Interestingly, the results showed no significant difference in weight loss between the two groups. Both groups lost approximately the same amount of weight, with the TRE group losing 2.3 kg and the usual eating pattern (UEP) group losing 2.6 kg. Additionally, no significant changes in glucose homeostasis measures were observed between the groups.

These findings suggest that the benefits of TRE seen in prior studies could be attributed to unintended reductions in caloric intake, as weight loss was not observed in the setting of calorie-controlled diets. Importantly, the study was conducted under highly controlled conditions, which may impact its applicability in real-world settings.

The limitations of the study included its relatively small size, the majority of participants being Black women—which may limit the generalizability of the findings—and the reliance on participant diaries to measure adherence to the eating window. Despite its limitations, this research provides valuable insights into the relationship between meal timing, calorie intake, and weight management.

For individuals considering TRE for weight loss, this study implies that any potential benefits are likely due, at least in part, to reduced caloric intake, rather than merely the restricted eating window. The effects of TRE on physical activity and behaviors remain subjects for further research.

This study was supported in part by the American Heart Association and is a testament to the complex nature of weight management and the importance of multifaceted approaches to tackling obesity. For more information about health conditions and symptoms, this study has been built with the help of Buoy Health.