You have finished dinner, you feel full, yet half an hour later you find yourself in front of the fridge, searching for something to eat. If this sounds familiar, you are not alone.
The scope of the problem
Research indicates that approximately one-third of people snack every night after their evening meal. Among those aged 18 to 24, the figure is even higher, with four out of five unable to resist. Dietitian Dr Kristine Beaulieu warns that this habit can have serious consequences. She points to evidence showing that the more people eat within two hours of going to bed, the greater their risk of weight gain and obesity.
Why evening cravings are so common
Despite the fact that we go without food for longer while sleeping, research suggests our appetite naturally peaks in the evening, almost regardless of how much we have eaten earlier in the day. Professor James Betts, who studies how the body handles food and energy at the University of Bath, explains that a major factor is the hunger hormone ghrelin, which is generally higher later in the day. While ghrelin is suppressed by meals, this effect is strongest after breakfast, not after lunch or dinner.
What you eat also matters. Meals rich in protein, fibre, and volume tend to keep us satisfied for longer. Betts notes that not having a nutritious or satiating evening meal can lead to a crash later, prompting people to snack. For some, the fear of waking up hungry during the night is a motivating factor, while habit also plays a role. Professor Suzanne Higgs, an expert in appetite at the University of Birmingham, says that if snacking often happens in the same setting, the surrounding cues can trigger cravings. For example, if someone usually snacks while watching TV, simply turning on the TV may make them feel like eating.
It is not just feelings of hunger that increase later in the day. Research suggests our appetite for calorie-dense foods also becomes stronger, driven by the brain's reward system rather than a genuine need for energy. Beaulieu, who splits her time between the University of Leeds and the University of Moncton in Canada, says: "Our liking and wanting for high-fat foods are greater later in the day compared to low-fat foods. That hedonic drive can override signals of fullness, making us want to snack or eat a dessert even though we're full." Even after a substantial evening meal, foods rich in sugar, fat, or salt can continue to activate reward pathways in the brain, helping explain why many people find themselves reaching for something more.
So when you find yourself standing in front of the biscuit tin at 9pm, it may not be a lack of willpower. Your biology is stacked against you.
Does late snacking affect sleep?
The evidence is mixed. Eating a large meal late certainly affects digestion and the body's normal preparation for sleep. However, when it comes to snacking, the research is less clear. There is some evidence that foods high in refined carbohydrates and added sugars, from white bread and white rice to biscuits and cakes, may be linked to poorer sleep. Researchers think this could be because such foods cause bigger swings in blood sugar levels and may alter some of the hormonal signals involved in regulating sleep and appetite. However, teasing out cause and effect is difficult. People with poor sleep may be more likely to snack on sugary foods. Professor Jonathan Johnston, a sleep and body clock expert at the University of Surrey, says: "Sleep deprivation is known to not only increase appetite, but also a desire for energy-dense foods." It means it is very difficult to draw firm conclusions on whether snacking in late evening disrupts sleep, says Betts. "The evidence is far from clear and perhaps may reflect that some people respond differently to others to different foods before bed."
What you can do about it
First, work out what is driving the snacking. If you are genuinely hungry, it may help to make earlier meals more filling. If snacking is mainly habitual, changing routines and planning snacks in advance can help. Higgs says: "Eating while distracted, for instance watching TV, can lead people to consume more because they pay less attention to how much they've eaten." But there is no need to ban evening snacks completely, says Beaulieu. A reasonable portion of something enjoyable is often more sustainable. Keep healthy options, such as fruit, yoghurt, and nuts, available. Even a little chocolate every now and then is not the end of the world. "It's OK to eat those craved foods once in a while in moderation," she says. The trick is to make the healthy choice the default. "If those craved foods aren't in the cupboard on a regular basis and a healthy option is, it means you are more likely to choose the healthier option."
