Late-Night Eating: Food Choice May Matter More Than the Clock, Experts Say

Most people have stood in front of an open refrigerator after midnight, and a health guide published by Insider on November 3, 2022 takes up the question of whether that habit does any harm. The answer from the experts it quotes is that nobody has settled it. Late-night eating can affect hunger hormones, blood sugar, and sleep, but the guide's central point is that what you eat, how much, and when matter more than the hour on the clock alone.

Dr. Sarah Musleh, an endocrinologist at Anzara Health, says the effects of nighttime eating differ with personal characteristics and with the type and amount of food. That makes a flat verdict of good or bad hard to give. She notes that some research links nighttime eating to negative health effects, though the guide's list of those effects did not survive in the text available here. The more encouraging finding is that for people who can't sleep on an empty stomach, some evidence suggests food choice outweighs timing.

The guide breaks the subject into four considerations. The first is what you eat and drink. Some foods and drinks affect sleep and digestion more than others. Tart cherries, plain yogurt, and nuts may promote restful sleep, while a bedtime latte paired with spicy chips is described as a poor choice. Kiwi and plain yogurt are offered as better picks than a candy bar or jalapeno nachos.

The second is portion size. A larger snack before bed can raise blood sugar, and higher blood sugar may contribute to insomnia. Carleara Weiss, a member of the American Academy of Sleep Medicine and a sleep educator at Aeroflow Sleep, says the body was not designed to digest large meals during sleep, particularly carbohydrates and sugar. Heavy meals take more effort to digest, she says, and that could impair sleep if they are eaten too close to bedtime. Her suggested alternative is modest: a handful of nuts with a glass of milk.

The third is timing, which ties into the circadian rhythm, the internal 24-hour clock that governs the sleep-wake cycle. Weiss says eating close to bedtime, whatever the food, disrupts that rhythm because digestion needs to slow down during sleep. She recommends finishing the last meal or snack two to three hours before bed. For someone who goes to bed at 10 pm, that means closing the kitchen by 8 pm. The right cutoff depends on the individual's bedtime.

The fourth is physical activity, where the evidence is less settled. Some research suggests intense exercise may suppress hunger hormones, which could leave people less hungry at night. Tom Holland, an exercise physiologist, stresses that results are mixed. Some evidence shows exercise has little effect on appetite, and overall fitness level may shape how hungry someone feels afterward, with wide variation between people. Experts generally recommend about 150 minutes of exercise a week, roughly 30 minutes on five days. On workout timing, older evidence suggests intense exercise before bed could disrupt sleep, while other research finds people who exercise late in the day may sleep more deeply. Holland's advice is to listen to your body and adjust. For those who get hungrier after exercise, he suggests a snack with complex carbohydrates and protein, such as a protein bar or shake, and a sleep-friendly snack if the workout is late.

The guide also says that paying attention to daytime routines and snacking can reduce nighttime hunger, and that someone named Lustig advises choosing sleep-associated foods when hunger strikes before bed. The specific tips in those sections are not detailed in the available text.

The takeaway is cautious. No conclusive evidence shows that eating at night is automatically harmful, but certain foods before bed may disrupt sleep. Leave two to three hours before bed if you can, choose small and sleep-friendly snacks if you can't, and treat the unsettled research on exercise and hunger as a prompt to test what works for you.