Why do you crave sweets after a bad night’s sleep?

Maybe you’re stressed about work. Or you have a new baby (or an older kid in a sleep regression). Or you’re in perimenopause. Whatever the reason, a bad night’s sleep happens to all of us at some point. As if the tossing and turning weren’t bad enough, there’s the exhaustion the next day…and an especially strong craving for sugar. 

Nope, this isn’t some sleep-deprived hallucination. When you’re running on less sleep, you may be drawn to everything sweet in sight — one of the various ways a lack of sleep can affect your weight. Here’s why your body is trying to lure you down a sugary path plus the expert tips that can help you stay on track until you can get a better night’s sleep.

Key Takeaways

• It’s not your imagination: not sleeping well really does make your body crave sugar more intensely.

• Lack of sleep causes sugar cravings by affecting your hunger and fullness hormones, your cortisol level, and the reward centers in your brain. 

• The best plan to reduce sugar cravings and blood sugar crashes are by starting your day with protein and fiber, staying hydrated, trying to unwind, being gentle with yourself when you do have cravings, and limiting caffeine later in the day.

You’re not imagining those candy cravings or using your exhaustion as an excuse to eat whatever you want. Even a single bad night shifts hunger and fullness signals and cranks up cravings. It’s biology, not weak willpower. 

“Sleep deficiency changes the balance of hunger and fullness hormones, while also making the brain's reward centers more responsive to highly-palatable foods. Sugary foods are appealing because they provide fast energy and trigger reward pathways that feel particularly satisfying when we're tired,” says Lauren Hale, Ph.D., a professor at Stony Brook University Renaissance School of Medicine and founding editor-in-chief of Sleep Health: Journal of the National Sleep Foundation. In other words, those cravings aren’t a lack of willpower; they’re “a predictable biological response to not getting the restorative sleep our bodies need.”

It’s not just one thing causing you to reach for chocolate, candy, or anything sweet when you’ve slept poorly; it’s a four-way intersection of factors that amp up your sugar cravings. Here’s what’s happening in your body when you haven’t slept well:

1. Your hunger hormones flip 

“Sleep deprivation can throw your hunger hormones out of balance. It increases ghrelin, the hormone that tells you ‘I'm hungry,’ and it also suppresses leptin, the hormone that tells you ‘I'm full,’” says Ellie Abramsky, M.S., RDN, a Registered Dietitian with Weight Watchers. “This shift can leave you feeling genuinely hungrier throughout the day, specifically for quick-energy foods like carbs and sugar.”

2. Your brain’s reward system takes over 

When you haven’t slept well, your brain ramps up reward-seeking behavior…and sugary foods feel even better than usual. “The brain's reward centers become more responsive to highly-palatable foods,” Hale says, which tend to be ultra-processed foods that are loaded with added sugars, fat, or salt (or the trifecta!). “Sugary foods trigger reward pathways that feel particularly satisfying when we're tired,” she says. It’s a double whammy: Not only are sweets more tempting than normal when you’re tired, but they also feel better than usual when you consume them.

3. Cortisol rises

“Poor-quality sleep can also act as a stressor on the body, driving up cortisol levels. High cortisol signals to your brain that you need fast, high-calorie energy to handle the ‘stress,’ which triggers intense cravings for sweet comfort foods,” says Abramsky, who notes that sometimes the cravings can show up for salty carbs instead of (or in addition to) ones for sweets. This could explain why nothing on earth has ever seemed as desirable as chocolate-covered pretzels.

4. Your blood sugar and energy dip

Lack of sleep, which causes cortisol and inflammatory stress, can also make your cells temporarily less sensitive to insulin. “When insulin sensitivity drops, your body has a harder time moving glucose from your blood into your cells for fuel. Combined with baseline fatigue, your brain usually seeks out fast-acting simple carbohydrates — a.k.a. sugar — to get that quick energy spike,” says Abramsky.

Our brains evolved over thousands of years, and they’re no dummies: A tired brain is shouting at you to consume the fastest, most rewarding fuel to restore its energy. That, in its simplest form, is sugar.

Sugar feels good when you’re exhausted — better than usual, even — and it helps…temporarily. “Sugar can give you a brief sense of increased energy, but it's usually short-lived,” Hale says. No surprise here, but “sugar can't replace the restorative benefits of sleep.”

We’ve all experienced the loop: You sleep badly and drag through the morning. You crave anything sweet and try to get through your exhaustion with a Band-Aid of sugar, caffeine, or both (hello, mocha latte). For a bit, you feel okay, even good enough to forget you were up half the night. Then, you crash — and feel worse than before the sugar and caffeine. 

“Your brain usually seeks out fast-acting sugar to get that quick energy, which is usually followed by a crash, which fuels a cycle of even more carb cravings,” says Abramsky. Late-in-the-day sugar and caffeine — and the blood-sugar rollercoaster — can also impact the next night’s sleep. And that then fuels another day of intense cravings. That said, you don’t have to get stuck in the cycle.

Once you’re aware of what your exhausted body is up to, you can get ahead of it and better handle food cravings with a few key steps:

Protect your sleep 

It’s ideal to get 7-9 hours of rest every night. If you have a bad night’s sleep, try not to stress or put pressure on it; it’s just one night, and you’re going for a pattern of healthy rest. To sleep better tonight, and every night, try to follow these tips:

• Create a comforting wind-down routine (reading, journaling, a bath, meditating, or anything without a screen) so your body knows it’s time to relax.

• Go to bed and wake up on a consistent schedule.

• Avoid alcohol and caffeine for several hours before bedtime.

• Keep your bedroom cool and dark.

Don’t over-restrict 

The day after a bad night’s sleep is not the day to tighten the screws on your diet. Be gentle with yourself and remember that your intense cravings are just your body trying to help you get through your exhaustion. Besides, trying to rigidly restrict sugar when you're exhausted usually backfires. 

"Extreme restriction can rev up psychological cravings on top of the physiological drives you're already fighting,” Abramsky says. Instead, she recommends you “aim for a mindset of gentle awareness: Recognize that your body is searching for energy, then satisfy the craving intentionally — maybe by pairing the sweet with a protein or fiber anchor, or by slowing down to eat it while sitting and screen-free. Then, don't beat yourself up. You haven't ‘ruined’ anything.”

Front-load protein and fiber 

When you’ve slept badly and know you’re going to be fighting biology all day, one of the best things you can do is to try to keep your blood sugar steady. Protein and fiber are always important, but they become even more key to help hold off intense sugar cravings. “The best strategy is to pair protein, fiber, and healthy fats with carbohydrates to support steadier energy throughout the day,” Hale says. Abramsky agrees, saying that starting the day this way will help anchor your blood sugar, which is key when cortisol is elevated and your hunger and satiety hormones are out of sync. “Fiber slows down digestion, while protein promotes satiety and blunts the spike-and-crash cycle that fuels non-stop sugar cravings later in the afternoon,” she says.

Plan for tired days

If you know you’re entering a stressful period (travel, a big life transition, an intense time at work, whatever) that may mean less restful sleep, you can prepare by having some easy, satisfying options at the ready. That way, you have a plan — and the groceries in your home — to put together a simple breakfast that checks the protein and fiber boxes to steady you for the day. Abramsky recommends these low-effort morning meals that combine both to help stabilize your blood sugar:

• Whole-grain toast topped with mashed avocado, plus hard-boiled eggs or cannellini beans

• Greek yogurt with berries and chia seeds

• Instant oatmeal prepared with protein powder and topped with fruit

Manage stress 

Stress can work against you in two ways: it can increase your already-elevated cortisol levels, and it can make it harder to get to sleep the next night. That’s why learning how to manage stress is so important. Try yoga, meditation, mindful breathing exercises, or have a laugh, all of which are shown to reduce stress. When you’re feeling more resilient and relaxed, you’ll be better able to make it through a tired day — and get better sleep that night.

Just because you’re short on sleep, doesn’t mean you have to be miserable the next day. Here’s Hale’s recommendations for the best game plan to feel better:

• Starting with breakfast, eat balanced meals with plenty of protein and fiber.

• Get daylight exposure, ideally in the morning, to help let your body know it’s daytime and to help you go to bed that night.

• Stay hydrated.

• Engage in light physical activity, like a walk.

• Limit caffeine later in the day, as this can keep you awake that night (yes, even if you’ve been longing for your bed all day).

• Try the bedtime wind-down behaviors so you get a better night’s sleep.

“Doing these things will help you make it through the day — and also support you getting better sleep the next night as well,” Hale says.

Weight Watchers understands that sleep impacts weight, which is why the WW app includes sleep tracking. In fact, 78% of Weight Watchers members who have tracked their sleep in the app say it supports them in reaching their weight-loss goals.* And when you do have a bad night, tracking meals in the app can remind you to reach for a breakfast that’s high in protein and fiber — two things experts say can help stabilize your blood sugar and reduce sugar cravings.

Weight Watchers also provides support for your perspective on days when sugar comes calling. The Points system makes room for all different foods, and nothing is off-limits — especially not when you’re already fighting just to make it through the day. With Weight Watchers, health is about a long-term pattern of eating and lifestyle habits, not what happens in a single day.

It’s not your imagination. Not sleeping well really does make your body crave sugar intensely, by affecting your hunger and fullness hormones, your cortisol level, and the reward centers in your brain. But even when you’re tired, you don’t have to be controlled by cravings. You can start your day with protein and fiber, get daylight, stay hydrated, try to unwind and be gentle with yourself, and limit caffeine later in the day — so you can get a better night’s sleep and be back on your game tomorrow.