Poor sleep, stress and cravings: why a late night makes you want pastries the next morning

Two hunger messengers get scrambled when you don't sleep

Your body has two hormones whose job is to carry messages about eating:

• Ghrelin: the messenger that says "you're hungry, eat." Released in large amounts by the stomach when it's empty.
• Leptin: the messenger that says "that's enough, you're full." Released by fat tissue.

A famous 2004 experiment had healthy young men sleep only 4 hours a night for two nights. The result: ghrelin went up, leptin went down. They felt hungrier. And what they craved most was sweets and starchy foods.

Picture it like this: the hunger speaker gets turned up, and the fullness speaker gets turned down.

A sleep-deprived brain sees food differently

It isn't only hormones. Your brain also changes how it "sees" food.

In 2013, scientists tested one sleepless night. In the morning, participants looked at pictures of food while their brains were scanned. The brain area in charge of weighing things up and reasoning was less active. The area linked to desire reacted more strongly. Sleep-deprived people wanted to pick higher-calorie foods.

A 2017 review pooled many studies. Its estimate: after short sleep, people eat about 385 extra calories the next day. That's about a medium bubble milk tea, even though you never planned to drink one.

Stress: why do we reach for sweets?

Under long-term stress, your body releases more cortisol, a hormone that helps us cope with pressure. Cortisol can increase appetite, especially cravings for sweet and fatty foods.

A 2001 study had participants take a stressful test. Those who released more cortisol ate more afterward, and chose more sweet food.

Sweets give your brain an instant feel-good moment. So comfort eating is a very human reaction. It's just that if it becomes your main way to let off stress, you can slip into a loop. Tired, eat sweets, feel sluggish, tired again.

Some people eat less when stressed, too. Everyone reacts differently.

Fix your sleep first, your menu second

Here's the surprise of this article. Sometimes a good way to crave less sugar isn't in the kitchen, it's in the bedroom.

Sleep experts advise adults to get about 7 hours or more a night. A few habits help you get closer to that number:

1. Go to bed and wake up at the same time, weekends included. Keep the difference to about an hour at most.
2. Avoid caffeine from early afternoon if you have trouble sleeping.
3. Keep dinner not too full and not too close to bedtime.
4. Turn off bright screens about 30 to 60 minutes before bed.
5. Get a few minutes of morning sun. Early light helps your body clock run on time.

When the craving has already arrived: a few gentle responses

Some days you still have to stay up late. When that happens:

• Eat a breakfast with protein. Eggs, milk and tofu keep you full longer and cut down on mid-morning snacking.
• Prepare snacks in advance: fruit, yogurt, a handful of nuts. When they're ready, you have fewer decisions to make mid-craving.
• Drink a glass of water first. Tiredness and thirst sometimes get mistaken for hunger.
• If you want something sweet, have a small portion and sit down to enjoy it properly. One piece of cake savored slowly usually satisfies more than a whole box eaten in a rush.
• Add another way to let off stress: a 10-minute walk, a call to a friend, a few slow breaths.

And don't beat yourself up. A day of sugar cravings from poor sleep is your body sending a signal, not you failing.

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