Studies have shown that sleep deprivation causes people to crave high-fat, high-sugar, and calorie-dense foods. Consistently, sleep deprived test subjects choose these foods over low-calorie or fruit/veggie options.
Not only do food preferences change, but even the way you taste food changes. Poor sleep actually leads to changes in how intensely people taste savory and sour flavors, contributing to cravings for foods like chocolate, jerky, and chips.
What causes these changes? Poor sleep throws brain-signaling hunger hormones out of whack. Levels of the hunger-inducing ghrelin are increased, while the anti-hunger hormone leptin is lowered. It’s not clear why this occurs, but it may be due to higher sympathetic nerve activity — the stress response — caused by poor sleep.
Within the brain itself, sleep loss also directly affects neural activity. Poor sleep leads to increased activity in a distinct region of the brain that responds when you look at food. Without healthy sleep, your brain is told to feel hungrier, and it will also change how you sense and respond to food.
Dave Gennert is a contributing writer for Eight Sleep and a graduate student at Stanford University in the Department of Genetics. His research is focused on epigenetics in the immune system.