Overweight and obesity are well‐established modifiable chronic disease risk factors that affect >70% of US adults. The limited success of behavioral approaches targeting calorie restriction, modified diet composition, and increased physical activity to control overweight and obesity have prompted the development of alternative strategies that can increase success rates.
Experimental and mechanistic studies suggest that the timing of food intake (eg, through intermittent fasting or time‐restricted feeding) could regulate metabolic function and reduce body weight. Specifically, time‐restricted feeding, restricting food intake to 4 to 12 hours per day without reduced calorie intake, has been associated with improved body weight homeostasis and is a proposed weight reduction strategy.
However, in randomized clinical trials, time‐restricted meal regimens resulted in similar weight loss compared with eating throughout the day but had beneficial effects on cardiometabolic risk factors, including abdominal fat loss, glucose regulation, insulin resistance, blood pressure, and lipid profile. Nevertheless, these studies were limited by small sample sizes, relatively short durations, and populations with specific conditions such as prediabetes or overweight/obesity.
Eating less overall and fewer large meals may be a more effective weight management strategy than intermittent fasting
This study evaluated the association between time from the first meal to last meal with weight change. Nearly 550 adults (18 years old or older) from three health systems in Maryland and Pennsylvania with electronic health records were enrolled in the study. Participants had at least one weight and height measurement registered in the two years prior to the study’s enrollment period (Feb.-July 2019).
Overall, most participants (80%) reported they were white adults; 12% self-reported as Black adults; and about 3% self-identified as Asian adults. Most participants reported having a college education or higher; the average age was 51 years; and the average body mass index was 30.8, which is considered obese. The average follow-up time for weight recorded in the electronic health record was 6.3 years.
Participants with a higher body mass index at enrollment were more likely to be Black adults, older, have Type 2 diabetes or high blood pressure, have a lower education level, exercise less, eat fewer fruits and vegetables, have a longer duration from last mealtime to sleep and a shorter duration from first to last meal, compared to the adults who had a lower body mass index.
The research team created a mobile application, Daily24, for participants to catalog sleeping, eating and wake up time for each 24-hour window in real time. Emails, text messages and in-app notifications encouraged participants to use the app as much as possible during the first month and again during “power weeks” — one week per month for the six-month intervention portion of the study.
Meal timing was not associated with weight change during the six-year follow-up period. This includes the interval from first to last meal, from waking up to eating a first meal, from eating the last meal to going to sleep and total sleep duration.
Total daily number of large meals ( more than 1,000 calories) and medium meals (500-1,000 calories) were each associated with increased weight over the six-year follow up, while fewer small meals (less than 500 calories) was associated with decreasing weight.
The average time from first to last meal was 11.5 hours; average time from wake up to first meal measured 1.6 hours; average time from last meal to sleep was 4 hours; and average sleep duration was calculated at 7.5 hours.
The study did not detect an association meal timing and weight change in a population with a wide range of body weight.
Future studies should work toward including a more diverse population, since the majority of the study’s participants were well-educated white women in the mid-Atlantic region of the U.S.
Prevention did not offer clear preference for frequent small meals or intermittent fasting. It noted that irregular patterns of total caloric intake appear to be less favorable for the maintenance of body weight and optimal cardiovascular health. And, altering meal frequency may not be useful for decreasing body weight or improving traditional cardiometabolic risk factors.
Di Zhao, Eliseo Guallar, Thomas B. Woolf, Lindsay Martin, Harold Lehmann, Janelle Coughlin, Katherine Holzhauer, Attia A. Goheer, Kathleen M. McTigue, Michelle R. Lent, Marquis Hawkins, Jeanne M. Clark, Wendy L. Bennett. Association of Eating and Sleeping Intervals With Weight Change Over Time: The Daily24 Cohort. Journal of the American Heart Association, 2023; DOI: 10.1161/JAHA.122.026484