The Effects of Eating Late at Night

Eating late at night can have potential health risks.
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What are the effects of eating late at night? Snacking late at night may be just what you need to take the edge off your hunger and fall asleep, but depending on what you eat, it could carry potential health risks. So keep in mind the problems of eating late at night.


If you find yourself occasionally eating at night, don't worry too much, but making it a habit is what can cause weight gain and increase your cholesterol.

Effects of Eating Late

Eating late at night can cause ​weight gain,​ according to a study reported by the University of Pennsylvania's Perelman School of Medicine. A June 2017 report in Penn Medicine News showed that participants not only gained weight, but they also had higher glucose and insulin levels and less energy.


Naomi Goel, the lead author of the study, said in the report, "Eating later can promote a negative profile of weight, energy, and hormone markers — such as higher glucose and insulin, which are implicated in diabetes, and cholesterol and triglycerides, which are linked with cardiovascular problems and other health conditions."

The study followed nine healthy adults who ate three meals and two snacks between ​8 a.m. and 7 p.m.​ for eight weeks. After a two-week break, the same group ate three meals and two snacks every day for eight weeks between ​noon and 11 p.m.​ The researchers found:


  • Weight increased.
  • Subjects metabolized fewer lipids and more carbs.
  • Insulin and fasting glucose measures rose.
  • Cholesterol and triglyceride levels rose — you want to keep those numbers below 200 ​milligrams​ per deciliter for cholesterol and 150 milligrams per deciliter for triglycerides.

Read more:Is It Bad to Eat Right Before Bed?

Changes in Appetite

The effects of eating late at night also cause changes in your appetite. You have a hormone called ghrelin, which lets you know when it's time to eat. Daytime eaters had peaks of this hormone earlier in the day.


You also have a hormone called leptin, which makes you feel full. For the daytime eaters, that hormone peaked later in the day. Researchers concluded that eating earlier in the day helps ​prevent overeating later.

Kelly Allison, an associate professor of psychology and a senior author of the study, said in the Penn article, "We have an extensive knowledge of how overeating affects health and body weight, but now we have a better understanding of how our body processes foods at different times of day over a long period of time."

Eating a Snack

The dangers of eating late at night are less if most of your food has been consumed during daytime hours. An April 2015 study in the journal ​Nutrients​ says that for people on an exercise program and those who have diabetes, a small snack before bed is OK.


By ​small snack​, the study authors said that any snack under about ​150 calories​ may help with muscle protein synthesis and for people with diabetes or obesity. In contrast, eating cookies, chips or other high-fat, high sugar foods may not satisfy your cravings, and may even keep you awake, according to the Cleveland Clinic.

Read more:4 Surprising Benefits of Eating at Night

When to Eat

Sometimes life gets in the way, and meals and snack times can vary. According to registered dietitian Jean Alvez, who spoke to the ​Chicago Tribune​ in January 2018, eating a balanced dinner at least ​two hours​ before you go to bed will help, even when your timing is out of whack.

A balanced dinner, said Alvez, should have a good mix of protein, fibers and fat. The next day, try to eat earlier and space out your meals and snacks evenly to keep your blood glucose levels from spiking.

Eat your last snack at least ​90 minutes​ before bedtime to allow your food to properly digest, says Lori Zanini, a California-based registered dietitian and certified diabetes educator with HealthCare Partners medical group, in a June 2015 article in ​U.S. News & World Report​. She suggests healthy, protein-filled snacks that include vegetables dipped in hummus, guacamole, almonds or Greek yogurt with cinnamon.