By Jessie Funchion, MS, RD, LDN
According to some recent studies, yes!
In a study on meal timing and weight loss, participants who reported eating their main meal earlier in the day (before 3:00pm) actually lost more weight than those who reported eating their main meal later in the day (after 3:00pm). Energy intake, dietary composition, estimated energy expenditure, appetite hormones and sleep duration was similar between both groups. But the late-eaters did report having smaller breakfasts or skipped breakfast more often than the early-eaters.
Another study found similar results – participants were randomized into two groups, each received 1400 calories a day, but one group received a 700 calorie breakfast and 200 calorie dinner, while the other group received the opposite. Both groups received a lunch that was 500 calories. The 700-calorie breakfast group showed greater weight loss and waist circumference reduction as well as greater reductions in triglycerides and blood sugar levels. Interestingly, the larger breakfast group also reported higher satiety with the meal plan than the small breakfast group.
Why, despite controlling for calorie intake, did the early-eaters experience better outcomes than the late-eaters? This may have to do with circadian rhythms, a topic that’s getting a lot of attention recently. Circadian rhythms are “physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in the environment.” Because of circadian rhythms, many of our metabolic processes operate at different rates over the course of a 24-hour period. For example:
– Insulin sensitivity is highest in the morning and midday and decreases throughout the afternoon and evening
– Triglycerides are often highest at night
– Thermogenesis is lowest at night and highest in the morning
These metabolic shifts help explain why eating later in the day makes it harder to lose weight, and why shift workers or nighttime eaters suffer higher rates of obesity and related health issues. This could also help explain why breakfast eaters overall have healthier weights than breakfast skippers.
The Take-Away: If you are trying to lose weight despite following a low calorie diet, switch up the timing. Try to front load calories and eat larger breakfasts and lunches, but smaller dinners.