We hear a lot about the benefits of intermittent fasting, but a six-year study in JAHA revealed that timing from the first meal to the last meal might not affect weight loss. Instead, the number and size of meals may be the more important factor.
Although intermittent fasting has become a popular weight-loss strategy, rigorously designed studies have yet to determine whether restricting the eating window can effectively control body weight in the long run.
For the study, the research team created a mobile app for 550 participants to catalog daily habits in real-time. Participants were regularly prompted to use the app during the first month and again during “power weeks”—one week per month for the six-month intervention period.
After six years, the authors found:
- Meal timing was not associated with weight change.
- This includes the interval from first to last meal, from waking to eating a first meal, from eating the last meal to going to sleep, and total sleep duration.
- Instead, the daily number of large (over 1k calories) and medium (500-1k calories) meals were each tied to increased weight.
- Fewer small meals (under 500 calories) was tied to decreased weight.
The Takeaway
There has been much debate about the weight benefits of intermittent fasting. Does the timing of when one consumes their meals really matter, or is it merely the fact that eating within a tighter window encourages reduced caloric intake? This study appears to provide evidence that it is more about eating smaller and fewer meals that benefits people, rather than when exactly those meals are eaten.
