Number of daily meals, not intermittent fasting, associated with long-term weight change
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In the general population, long-term weight change is strongly associated with the average daily number of medium and large meals but not with a specific time-restricted eating strategy, researchers reported.
In an analysis of electronic health record data for patients across three health systems, researchers found that the number of daily meals was positively associated with weight change over a median of 6.3 years; however, the time interval between first and last meal was not associated with weight change.
“In addition to windows between meals, the role of the frequency and size of meals on weight has been also controversial,” Wendy L. Bennett, MD, MPH, an associate professor of medicine at Johns Hopkins University School of Medicine, and colleagues wrote in the Journal of the American Heart Association. “Cross-sectional studies have shown that a greater meal frequency was either not associated, or associated with a reduced prevalence of abdominal and general obesity, while two large-scale prospective cohort studies showed that greater meal frequency was associated with increased weight gain and BMI.”
In a prospective study, Bennett and colleagues recruited 547 participants from three health systems included in the PaTH Clinical Research Network who had at least one weight and height measurement within 2 years before the enrollment window. The mean age of participants was 51 years; mean BMI was 30.8 kg/m2; 77.9% were women and 77.5% were white.
The participants downloaded and used a mobile app to record the timing of meals and sleep for at least 1 day for 6 months. Researchers assessed weight and comorbidities data at each outpatient visit from the EHR for up to 10 years before until 10 months after baseline and modeled weight trajectories.
The mean interval from first to last meal was 11.5 hours and was not associated with weight change. In adjusted models, each 1-hour increase in time from first to last meal at baseline was associated with a 0.005 kg average annual weight change (95% CI, 0.08 to 0.09). The annual weight changes during follow-up associated with time from wake up to sleep, time from last meal to sleep, and sleep duration were 0.02 kg (95% CI, 0.08 to 0.12), 0.07 kg (95% CI, 0.03 to 0.17) and 0.11 kg (95% CI, 0.06 to 0.28), respectively.
The number of meals per day was positively associated with weight change. The average difference in annual weight change associated with an increase of one daily meal was 0.28 kg (95% CI, 0.02-0.53), according to researchers.
Total daily number of large and medium meals was associated with increased weight during follow-up time, whereas the total number of small meals was associated with decreasing weight. The average annual weight changes associated with a daily increase of one large, medium or small meal were 0.69 kg (95% CI, 0.19-1.18), 0.97 kg (95% CI, 0.64-1.29) and 0.3 kg (95% CI, 0.53 to 0.07), respectively.
The researchers noted that the distribution of energy intake earlier during the day appeared to be associated with less weight increase after enrollment.
“Duration from first to last meal, as well as other meal patterns, did not show a clear association with weight trajectory,” the researchers wrote. “Our findings did not support the use of time-restricted eating as a strategy for long-term weight loss. Further large-scale studies with long follow-up time are needed to better characterize the association for time of eating with weight change.”