If you’ve been trying to lose weight, you’ve likely already done the work of reevaluating your food choices with a doctor or dietitian, and you’ve likely amped up your activity levels too. But there’s one crucial component to weight loss you may not have considered — and that’s sufficient sleep.
As it turns out, chronic sleep deprivation is pretty common, and it could be sabotaging your weight loss efforts.
The Journal of Clinical Sleep Medicine reported that sleeping fewer than 7 hours per night could increase the likelihood of weight gain, obesity, and other conditions, such as heart disease and stroke.
We looked at the science and talked with some pros to see what was up with sleep and getting to a healthy-for-you weight.
1. Sleep-deprived people may be more likely to overeat
“Sleep deprivation affects hormones that regulate appetite and satiety, which leads to overeating and poorer food choices,” says Janet Kennedy, PhD, clinical psychologist and founder of NYC Sleep Doctor.
A 2015 review of studies concluded that sleep deprivation could affect the hormones ghrelin, leptin, and adiponectin, which help regulate appetite. The researchers noted that chronic short sleep in children could affect these hormones and lead to unintended weight gain, though more research is needed to be sure.
2. Lack of sleep can make you crave unhealthy foods
A big part of weight loss is making nutrient-dense and balanced food choices, and it turns out that your sleep habits can affect that process too.
In a 2013 study, researchers asked a group of sleep-deprived people and another group of well-rested people to rate more than 80 foods, from potato chips to strawberries, based on how badly they wanted to eat that food at the time.
They found that the sleep-deprived people craved higher-calorie, less nutrient-dense foods like potato chips more than the well-rested people — regardless of how hungry they actually were.
The researchers determined that sleep helps regulate a part of your brain involved in governing your food choices, and sleep deprivation affects your frontal lobe and alters your brain state, making higher-calorie foods more appealing.
“When that hormone cycle is disrupted, we may find ourselves reaching for less-healthy options, including those high sugar, high fat foods,” says Kristi L. King, RD, a senior pediatric dietitian at Texas Children’s Hospital. “Best advice — plan ahead. If you know you’re going to have a busy week, plan your meals and snacks and package nutrient-dense snacks in advance, so all you have to do is grab and go.”
For instance, you can put together healthy snack bags to grab as you head out the door.
If you’re super tired and just don’t feel up to meal prepping, do what you can.
“Count on convenience foods and use the label to make wise choices,” says Caroline West Passerrello, RD, a spokesperson for the Academy of Nutrition and Dietetics. “Include foods with fiber and nutrients while limiting those with added sugars or high sodium levels.”
3. Sleep can change your appetite levels through insulin regulation
“Sleep affects the way the body responds to insulin,” says Nate Watson, MD, former president of the American Academy of Sleep Medicine. “Sleep deprivation promotes insulin resistance, so the body becomes less sensitive to insulin, making it less efficient in moving glucose from blood into the cells of the body.”
A small 2015 study found that sleep restriction in healthy men increased concentrations of non-esterified fatty acids at night and in the early morning, which could be a factor in developing insulin resistance and a higher risk of diabetes.
Essentially, sleep deprivation changes the way your body metabolizes glucose, a kind of sugar your body breaks down from foods and uses as fuel. This can increase your insulin levels and mess with your appetite and hunger.
4. Sleep-deprived people can struggle with managing their diet
For most people, mindful eating strategies are an important part of maintaining a moderate weight. Sticking to your eating plan, staying present while eating, and being active can be helpful, but a lack of sleep may lead you to make less-nutritious choices.
According to a 2015 study from Clemson University, sleep deprivation is linked to impulsive decision making.
That means when you’re not rested enough, you might be more likely to ditch your workout buddy, impulsively eat less nutritious food, eat when you’re bored or emotional, or generally make decisions that aren’t in your best weight loss interests.
5. Sleep is important for working out
If being active is part of your weight loss plan, take note: Studies show that sleep deprivation can affect your athletic performance by tanking your endurance.
A 2017 review of studies found that increased physical activity promoted better and longer sleep, especially in older adults, and that sleep had positive effects on activity. It seems that sleep and activity rely on each other to help you function at your peak.
Sleep likely plays a big role in post-exercise recovery too. So, for optimal performance in the gym, make sure you’re getting your Zzz’s.
According to Kennedy, it’s hard to definitively tell whether sleep deprivation is affecting your weight loss — or by how much. But evaluating your sleep habits can still lead to good outcomes:
“Sleep, diet, and activity are all connected,” she says. So, if you think you might be sleep-deprived, following basic sleep hygiene can make a huge difference.
Here are a few of Kennedy’s best tips for better sleep (and healthy weight loss):
- Get up at around the same time each day so your body can get into a rhythm.
- Don’t use your bed as a hangout spot — try to avoid getting into bed until you’re ready to wind down.
- Unplug from phones, tablets, and computers at least an hour before bed.
- Create a simple bedtime routine to signal to your body that it’s time to sleep.
- Avoid heavy meals close to bedtime.
- Exercise (but not right before bed).
- If you have racing thoughts, don’t just hang out with them — get up and write them down, and then do something relaxing to distract your mind while your body’s fatigue takes over.
It’s true: Your sleep schedule, activity level, and eating all intermingle and affect everything in your body. Your best bet is to prioritize good, consistent sleep to make sure your body and mind are at their best. This will help you make mindful, nutrient-dense food choices and keep your activity up to get to the healthiest weight for you.
Nina Bahadur is a freelance writer, editor, and consultant based in NYC.