There are many theories about meal timing. 

For example, you may have heard that eating breakfast soon after waking “kick-starts” your metabolism or that eating before bed increases fat gain.

While most of these ideas are false, we know there’s some interplay between our sleep and eating patterns.

Research shows there’s a link between nutrition and circadian biology. Circadian rhythms, which influence digestion, nutrient metabolism, appetite regulation, and hormone secretion, affect eating habits and vice versa.

This is why scientists continue to study chrononutrition, which explores how changes in sleep influence diet and how changes in diet impact sleep.

One area of particular interest in this field is the connection between eating behavior and “social jet lag.”

Social jet lag refers to the lethargy you feel after the weekend when social events upset your usual sleep and wake times. It’s of interest to scientists because research shows it can significantly affect your eating habits and metabolic health.

For instance, in a 2022 review conducted by scientists at Iuliu Hatieganu University of Medicine and Pharmacy, researchers found that people who don’t have a consistent bedtime, whether because of social jet lag or day-to-day inconsistency, tend to eat a less healthy diet (fewer fruits, vegetables, whole grains, and beans and more sugar and soda, for example) than those who go to bed at the same time every night.

Unlike people with a regular bedtime, those with social jet lag usually also experience more hunger and cravings for calorie-dense foods, even after eating.

The researchers also found that in studies of obese people, those with social jet lag typically ate more calories, carbs, and fat than people without social jet lag. 

As with any research based on observational studies, we can’t say for certain that social jet lag causes poor eating behavior, only that the two are correlated. 

That said, the evidence seems to indicate that going to bed around the same time every night helps you make better food choices, eat fewer calories, and control your appetite, which is likely why several studies show that people who have a regular bedtime are less likely to be overweight or obese than those who turn in at different times each night. 

Of course, socializing is often anathema to keeping a consistent sleep schedule, so you need to strike a balance. It’s fine to occasionally break your routine on the weekends, but know that this can make it more difficult to control your hunger and make good food choices. 

(If you like nutrition tips like this and want an even more in-depth guide to dieting, check out my fitness books for men and women, Bigger Leaner Stronger and Thinner Leaner Stronger.)

Takeaway: Going to bed at the same time most nights (including on the weekend) may make dieting easier by helping you make healthier food choices and control cravings, hunger, and calorie intake.

This article is part of our weekly Research Review series, which explores a scientific study on diet, exercise, supplementation, mindset, or lifestyle that will help you gain muscle and strength, lose fat, perform and feel better, live longer, and get and stay healthier. 

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