Is There a Link Between Sleep Deprivation and Obesity?
Meanwhile, lack of sleep depletes our motivation, willpower, and decision-making abilities, meaning we’re more likely to cancel that Pilates class or skirt right past the produce section during our grocery run. Studies show that people with sleep loss eat fewer fruits and vegetables, which contain nutrients like fiber that are key to feeling full and maintaining steady energy levels throughout the day. “When you’re sleep deprived, you’re simply not in the mindset to make thoughtful, healthy choices. You’re too tired to plan, too drained to cook, and too overwhelmed to even think clearly,” says Chevy Mermelstein, a Montreal-based sleep coach. “That’s when we start reaching for the easy stuff—processed, packaged foods, sugary snacks, caffeine, or anything that gives a quick boost. Your body is desperate for energy and relief.”
Underlying all of this are the complex, hormonal reasons that sleep affects weight management. Insufficient sleep—due to short sleep duration, poor sleep quality, or both—alters the balance of the hormones that regulate things like appetite, metabolism, and fat storage. Without enough sleep, your body produces less leptin, known as the satiety hormone. Lower levels of leptin mean you’re less likely to feel full after you eat and more likely to keep reaching for more servings. On the flip side, lack of sleep is associated with an increase in ghrelin, the hunger hormone. Increased ghrelin levels have been shown to not only make people increase their overall food intake but also to specifically crave higher-calorie foods.
Another hormone that increases when you’re in a state of sleep deprivation is the so-called “stress hormone” called cortisol; higher cortisol levels are linked to increased abdominal fat, as well as muscle breakdown. They also affect insulin sensitivity, which decreases when you don’t get enough sleep. Put simply, lower insulin sensitivity means your body is less efficient at processing carbs, leading to elevated blood glucose and more storage of excess energy as body fat. (Not ideal at times when you’re grabbing chips straight from the bag to get through a sleepy afternoon slump.) And sorry, poor sleepers, but that’s not all. “Poor sleep also compromises slow-wave sleep, which is when growth hormone is released,” says Dr. Anne Marie Morse, a double board-certified neurologist and sleep medicine specialist and founder of DAMM Good Sleep. “That hormone is critical for recovery, metabolism, and preserving muscle mass.”
Another challenge: The specific types of foods that insufficient sleep makes us crave may cause sleep disturbances the next night. Studies have linked higher intake of saturated fat and lower intake of fiber with lighter, less-restorative sleep, and increased intake of sugar and carbohydrates with a higher incidence of sleep disturbances. Since weight gain and obesity can negatively impact quality of sleep, “This cycle of poor sleep and poor food choices can lead to a vicious cycle of weight gain and further sleep issues,” Dr. Ren-Fielding says.
The good news: Improving your sleep even slightly could have a noticeable impact on weight loss. The first step in breaking a sleep loss cycle is to look at your sleep habits and think about ways that you can improve your sleep hygiene (the daily habits that set us up to get great rest). While maintaining a consistent bedtime is important, making yourself go to bed earlier may be the hardest place to start, since hitting the pillow before you feel sleepy can lead to anxious tossing and turning. Instead, look at your wake-up time as the first place to adjust your sleep-wake cycle. “To regulate your circadian rhythm, get out of bed at the same time each morning, even if you slept poorly,” says Jessica Fink, a sleep specialist in Austin, TX. “Our circadian rhythm determines the timing of sleep and wakefulness. Erratic rise times dysregulate this rhythm. It’s like jet lag without the vacation.”
