By Julie Upton, RD

I'm a world champion at sleeping, but I know my diet is worse when I don't get my regular eight to nine hours. I tend to reach for more food—especially carbs—to help wake me up. It never works and probably makes me feel less energized.

Research now backs up why less sleep equals more calories.

Several studies have found that getting at least six hours of sleep appears to help us maintain a healthier weight. Researchers now know that brain hormones and chemicals responsible for hunger and fullness are closely tied to our natural circadian rhythms. When we get less sleep, appetite increases—as do cravings for high-calorie foods.

A study published in the prestigious medical journal Obesity revealed that night owls eat more of their calories in the evening and are more likely to be overweight than adults who go to bed at a reasonable hour and eat most of their calories before 8 p.m. The researchers found that people who stay up late eat about 250 more calories a day, along with more fast food and soda and less fruits and vegetables.

Another interesting finding was that eating after 8 p.m. was a predictor of being overweight, regardless of when subjects went to bed or how many hours they slept. In addition, post-8 p.m. eating predicted total caloric intake.The study found that night owls ate some 754 calories after 8 p.m. while normal sleepers ate 376.


A bowl of ice cream at night has the same calories as a bowl of ice cream in the morning, but research shows there may be other real hormonal and metabolic differences that makes those nighttime calories less waistline-friendly.

First, people snacking at night are probably doing so while watching TV, playing video games, working, or buying stuff online. It's natural to overeat when munching when distracted, and those calories are less satisfying so it takes more to feel full. Second, research in animals and humans shows that circadian rhythms of eating and sleep are ordinarily synchronized so we do not eat nocturnally. Night eating causes a disruption in hormones that regulate appetite and hunger and make the body more likely to store calories as fat.

What to do
An ideal diet distributes calories so you eat most before dinner. Once you're done with dinner, try not to eat until bed to see if it helps you lose weight. If you're extremely hungry, plan a light nighttime snack of up to 200 calories, but make it something that contributes positive nutrients, like half of a sandwich, a piece of fruit, or whole grain crackers and a piece of low-fat cheese.