Morning Eating Habits May Boost Long-Term Weight Loss, Especially for Those with Genetic Predispositions

Recent research led by the Complutense University of Madrid indicates that consuming meals earlier in the day can significantly reduce the likelihood of weight gain, even among individuals with a high genetic risk for obesity. The study, published in the journal Obesity, highlights the importance of meal timing in managing long-term weight and mitigating genetic susceptibility.

In the study, researchers analyzed data from 1,195 overweight and obese adults engaged in a 16-week behavioral weight-loss program, followed by a long-term assessment approximately 12 years after treatment. Participants' meal timings were carefully tracked by calculating the midpoint of their daily food intake, averaging across weekdays and weekends. A polygenic risk score for BMI was generated based on nearly a million genetic markers.

Findings revealed that each hour of delay in the midpoint of meals was associated with nearly a 1 point increase in BMI at baseline and a 2.2% rise in body weight after 12 years. Notably, in individuals at the highest genetic risk for obesity, a one-hour delay in meal timing correlated with about a 2.21 kg/m² increase in BMI, while no such association was observed in lower-risk groups.

These results suggest that early meal timing may serve as a practical strategy to support weight-loss maintenance and offset genetic predisposition to obesity. The study emphasizes the potential for personalized dietary interventions that leverage meal timing to improve long-term health outcomes.

Understanding the influence of circadian rhythms and zeitgebers on metabolism further underscores the importance of synchronized eating schedules. Disruption in internal biological clocks, often caused by irregular eating patterns, can lead to metabolic misalignment, contributing to obesity and related cardiometabolic issues.

This research supports the idea that not only what we eat, but also when we eat, plays a crucial role in managing weight, especially for those genetically predisposed to obesity. Adopting earlier meal times could become a key component of personalized weight management strategies.

For more details, see the original study at: Obesity, 2025.