When it comes to losing weight, the top strategies will always be nutrition and physical activity, so it makes sense to focus on those two things the most. But, that doesn't necessarily mean they're the only ways you can drop weight. One significant addition? Quality sleep.
Numerous studies have connected poor sleep to weight gain—especially belly fat. For example, research commentary in Environmental Health Perspectives noted that shorter sleep has been correlated with obesity, hypertension, and other metabolic disorders. (Related: 15 Underrated Weight Loss Tips That Actually Work.)
Another study, published in the journal Sleep, found notable changes in body fat between short, average, and long-duration sleepers. Those outside the middle range of seven to eight hours were much more likely to experience gradual weight gain, even if they ate roughly the same amount of calories and got as much exercise as the average-duration sleepers.
This happens for several reasons, according to W. Chris Winter, M.D., president of Charlottesville Neurology and Sleep Medicine, and author of "The Sleep Solution." Here are the top changes that occur when you're skimping on shuteye.
Increased appetite and hunger: When you don't get enough sleep, your circadian rhythms get thrown off, and that tends to lead to overeating, Winter says. Even worse, you're more likely to crave high-calorie foods, especially salty or sugary snacks.
Higher stress levels: You simply feel less resilient when you're dealing with sleep issues, Winter says. You might be annoyed more quickly, or feel overwhelmed and frazzled. That can lead to a surge in your stress hormone, cortisol, and chronic elevation of that hormone in particular has been linked to increased belly fat.
More hormone issues: In addition to cortisol problems, poor sleep also negatively effects two other major hormones, leptin and ghrelin. Winter says these regulate hunger signals, making overeating even more likely.
Poor gut health: Your digestive system is responsible for much more than processing food; it's also the center of your immune system and emotional regulation. Even a few nights of bad sleep can throw this off and put you at risk. One study found that only two consecutive nights of short sleep led to disruption in gut health for study participants.
All of these effects are interlinked, says Winter. For example, if you feel stressed, you may eat more comfort foods to feel better, and that can leave you feeling sluggish and actually increase your cravings instead of diminish them. It can also be a vicious cycle: Eating junky foods may sabotage your sleep quality, further lowering your chances at effective weight loss.
"Many people find that when they focus on establishing good sleep habits, other areas of their lives start to fall into place, too," says Dr. Winter. "That includes their energy levels, food choices, exercise consistency, even their moods."
For more, be sure to check out The 5 Absolute Best Foods to Eat For Better Sleep.