A 2013 study published in the journal Obesity found that volunteers in a two-week lab experiment were hungriest at night, no matter when they woke up, how much they’d eaten during the day, and when they’d eaten their last meal. Even more fascinating, the volunteers’ nighttime cravings were on average for fatty, sugary, salty and starchy junk food.
“There are many complex reasons why people snack late at night,” says Suzanne Jezek-Arriaga, a nutrition and holistic health coach and the author of the book, Nourish to Flourish. “Sometimes it’s because of boredom, or your body could not be getting enough nutrition. If you are eating too many sweets, junk foods or carbohydrates, and not eating enough healthy fats and protein during the day, you can set yourself up for an insulin crash resulting in cravings.”
Additionally, Jezek-Arriaga says that the hormone cortisol, which controls the release of blood sugar from the liver, may also be to blame for late night binges. “If you are stressed, your cortisol level can go up, which will make you hungrier and make your blood sugar and insulin levels rise,” she says.
Cortisol levels typically go down at night, but staying up past your bedtime can cause them to spike again.
Midnight snacking brings on more health problems than just weight gain,” says Cara Walsh, a registered dietitian at Medifast Weight Control Centers of California. “According to a Danish study, late night eating can cause a myriad of health problems, including acid reflux and ― in the worst case scenario ― esophageal cancer.