Why Evening Snacking Happens, and How to Curb the Late-Night Cravings

You've finished dinner and you're comfortably full. Half an hour later you're standing at the kitchen cupboards anyway. According to research cited by the BBC, this is not a quirk of a few people: about a third of us snack every night after the evening meal, and among 18-to-24-year-olds the figure is four in five who cannot resist.

Dietitian Dr Kristine Beaulieu says that pattern is a concern. She points to evidence that the more people eat in the two hours before bed, the "greater the odds" of weight gain and obesity. Beaulieu splits her time between the University of Leeds and the University of Moncton in Canada.

Part of the explanation is simply timing. Even though we go longer without food while asleep, research suggests appetite naturally peaks in the evening, almost regardless of how much we ate earlier in the day. Prof James Betts, who studies how the body handles food and energy at the University of Bath, says a big factor is ghrelin, the so-called hunger hormone, which is generally higher later in the day. Meals tend to suppress it, he says, but that really only happens after the first meal of the day, not after lunch or dinner.

What ends up on the plate matters too. Meals rich in protein, fibre and volume tend to keep people satisfied for longer. Betts says that an evening meal lacking nutrition or staying power can lead to a "crash" later on, and that is when people snack. For some, fear of waking up hungry in the night is the motive. For others, it is habit.

Prof Suzanne Higgs, an appetite expert at the University of Birmingham, explains how habit works: if snacking regularly happens in the same setting, the surrounding cues can begin to trigger cravings. Someone who usually snacks in front of the television, she says, may feel like eating simply because the TV has come on.

There is also the brain's reward system. Research suggests that our appetite for calorie-dense food strengthens later in the day, driven by reward rather than any real need for energy. Beaulieu says our liking and wanting for high-fat foods are greater in the evening than for low-fat foods, and that this "hedonic drive" can override signals of fullness, so we want a snack or dessert even when full. Foods rich in sugar, fat or salt can keep activating the brain's reward pathways even after a substantial dinner. So the biscuit tin at 9pm may not signal weak willpower; the biology, as the article puts it, is stacked against you.

The experts' advice starts with working out what is driving the habit. If you are genuinely hungry, making earlier meals more filling may help. If the snacking is mostly habitual, changing routines and planning snacks in advance can help. Higgs adds that eating while distracted, such as in front of the TV, can lead people to eat more because they pay less attention to how much they have had.

Beaulieu does not recommend banning evening snacks altogether. A reasonable portion of something enjoyable is often more sustainable, she says, and a little chocolate now and then is not the end of the world. Healthy options such as fruit, yoghurt and nuts should be kept on hand. Her central trick is to make the healthy choice the default: if craved foods are not regularly in the cupboard and a healthier option is, you are more likely to pick the healthier one.