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You've had dinner and your stomach feels full, but half an hour later, you can't help but open the kitchen cabinets to look for snacks. Does this situation sound familiar?
Research shows that about one-third of people snack after dinner every night; among 18 to 24-year-olds, the figure is as high as four-fifths. People find it hard to resist the temptation to eat before bed.
Nutritionist Dr Kristine Beaulieu said this could cause health problems. She cites research that shows that the more frequently you eat within two hours of bedtime, the "greater your chance" of gaining weight and developing obesity.
So, why is it so easy to get cravings at night? Is there any way to control this appetite?
Appetite peaks at night
Although we go without food for long periods of time while we sleep, research shows that our appetite naturally peaks in the evening and is barely affected by how much we eat earlier in the day.
Professor James Betts, who studies how the body processes food and energy at the University of Bath in the UK, said one important factor is that levels of the body's "hunger hormone" - ghrelin (ghrelin) - generally become higher later in the day.
"Eating normally suppresses ghrelin, but this mainly occurs after the first meal of the day, not after lunch or dinner," he said.
However, what you eat is equally important. Foods rich in protein, fiber and adequate portions usually keep us feeling full for a longer period of time.
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Bates said if the meal lacks nutrition or doesn't make you feel full, you may experience an "energy crash" later, making you tempted to snack.
For others, the fear of waking up hungry in the middle of the night is a motivator for eating before bed. Also, habits come into play.
Professor Suzanne Higgs, an appetite expert at the University of Birmingham, said: "If a person often snacks in the same environment, things going on around them may gradually trigger appetite."
"For example, if someone is used to eating snacks while watching TV, simply turning on the TV may trigger the thought of eating."
Why are sweet treats so irresistible?
It's not just hunger that increases later in the day. Research shows that our appetite for high-calorie foods also becomes stronger, and this is primarily driven by the brain's reward system, rather than the body's actual need for more energy.
Dr. Beaulieu holds appointments at the University of Leeds in the UK and the University of Moncton in Canada. "We like and crave high-fat foods more later in the day than low-fat foods," she says.
"This drive for pleasure may override the body's satiety signals, causing us to still crave snacks or desserts even when we are full."
Foods high in sugar, fat, or salt can continue to stimulate the brain's reward mechanism even after a rich dinner, which helps explain why many people are constantly tempted to eat more.
So standing in front of the cookie jar at 9pm doesn't necessarily mean you lack self-control. Your biology may be hard-wired to resist.
Will eating snacks before bed make you sleep worse?
Current research findings are inconsistent. What is certain, however, is that eating large amounts of food late at night can affect digestion and the body's normal preparation for sleep.
So what about snacking? The findings in this area are less clear-cut.
There is some evidence that foods rich in refined carbohydrates and added sugars, such as white bread, white rice, cookies and cakes, may affect sleep quality.
Researchers believe that the reason may be that such foods can cause large fluctuations in blood sugar levels, which may change some hormonal signals responsible for regulating sleep and appetite.
However, it is not easy to clarify the causal relationship between the two. People with poor sleep quality may also be more likely to eat snacks high in sugar.
Professor Jonathan Johnston, who studies sleep and circadian clocks at the University of Surrey in the UK, said: "It is well known that lack of sleep not only increases appetite, but also increases cravings for high-calorie foods."
That means it's difficult to draw firm conclusions about whether late-night snacking affects sleep, Bates said.
"The current evidence is far from clear enough, and may also reflect that different people may have different body reactions when eating different foods before bed," he said.
How to snack in a healthier way?
First, find out why you're snacking.
"Eating while doing other things, such as watching TV, may cause people to eat more because they are less aware of how much they have eaten," Higgs said.
However, Beaulieu says it's not necessary to completely ban yourself from snacking in the evening.
She said: "It's completely okay to occasionally eat in moderation the foods you particularly crave."
The key, she believes, is to make healthy choices a daily default.
“If your kitchen cabinets don’t usually have those crave-worthy foods but there are healthy options, you’ll be more likely to choose healthier foods.”
This article was originally written in English. We used artificial intelligence to assist in translation and was reviewed by BBC journalists before publication. Learn more about how we use artificial intelligence.
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