Meal frequency, not timing, factors in weight gain over time

The frequency of meals, rather than the timing, is a stronger determinant of long-term weight change, a study has found.

In this multisite prospective cohort study, 547 adults (mean age 51.1 years, 77.9 percent women, 77.5 percent White) downloaded and used a mobile application to record the timing of meals and sleep for at least 1 day. Researchers collected data on weight and comorbidities at each outpatient visit from electronic health records (EHR) for up to 10 years. They used mixed linear regression to model weight trajectories.

The mean number of weight measurements in the EHR among the participants was 23.7 overall, 21.3 before enrolment, and 3.4 at 6 months after enrolment. The mean interval from first to last meal, waking up to first meal, and last meal to sleep were 11.5, 1.6, 4.0 hours, respectively. The participants slept for a mean of 7.5 hours daily.

Participants with higher vs lower body mass index levels at enrolment tended to be Black and older, have diabetes or hypertension, have a longer duration from last mealtime to sleep, have lower education, physical activity, and fruit/vegetable intake, and shorter duration from first to last meal.

Weight change over a mean follow‐up of 6.3 years showed no association with the mean interval from first to last meal but did so with the number of meals per day. Every increase of one meal per day was associated with an average increase of 0.28 kg (95 percent confidence interval, 0.02–0.53) in annual weight.

The present data do not support the use of time‐restricted eating as a strategy for long‐term weight loss in a general population.