Why does summer disrupt our appetite?

There’s a promise that comes up every year around this time. In the summer, I’ll eat better, lighter meals—more salads, less of this and that. Then the real heat hits, and the plan falls apart in a curious way. At lunch, I hardly feel like eating anything, because when it’s in the high thirties, my body just craves shade and water. At night, when it cools down, you open the fridge as if seeking delayed revenge. In between, there’s the afternoon ice cream, the cold beer, and the snacks from the outdoor café that no one can resist. At the end of the month, the scale and the mirror contradict that initial promise, and you’re left with the feeling that your hunger simply went haywire without warning. The good news is that this isn’t a lack of willpower. It’s summer messing with—seriously—the signals that regulate what the body craves. And once you understand how it works, it stops being a mystery and becomes something you can manage.

The heat takes away your appetite at lunchtime and brings it back at midnight

The first factor in this confusion is the most physical of all. Digesting a meal generates heat—this is known as the thermic effect of food—and when the body is already struggling with high ambient temperatures, it avoids adding more heat to an overheated system. The result is a diminished appetite during the hottest hours of the day. Studies on temperature and eating habits show precisely this: the amount of food consumed tends to decrease as the environment warms up. The problem is that this hunger doesn’t disappear—it just shifts to a different time of day. When the sun goes down and the air cools, it returns with a vengeance, often in the form of a late dinner and whatever is eaten afterward, usually without much restraint. People convince themselves that they ate very little during the day—and in part that’s true—but the balance is settled entirely at night. The mistake lies in focusing only on the skipped lunch and forgetting everything that came after sunset, which is usually higher in calories and less thoughtfully chosen than what was avoided at 2:00 p.m.

Sleeping poorly in the heat makes you hungrier the next day

Few things ruin a night’s sleep as much as a hot bedroom. Sleep becomes shorter, lighter, and more interrupted, and this has direct consequences the next day. Research on sleep deprivation is consistent on one point: short nights are associated with increased hunger and higher calorie intake the next day, with a particular craving for carbohydrates and anything that’s quick and sweet. The most widely accepted explanation involves the balance between two hormones: leptin, which signals satiety, and ghrelin, which stimulates appetite, although the exact hormonal picture remains a subject of scientific debate. For our purposes here, the message is simple and practical. A bad night of heat sets the stage for a day of increased hunger, and summer is full of such nights. Anyone who experiences several of these in a row—between the stuffy bedroom and the long, drawn-out evenings—accumulates fatigue that the body tends to compensate for in the most immediate way it knows: food. It’s not weakness; it’s biology demanding quick energy from those who’ve had little sleep.

My routine went on vacation, and hunger followed

The body likes routines. It learns to anticipate meals that usually arrive at the same time and regulates hunger and satiety around that predictability. Summer does exactly the opposite. Mealtimes stretch out, the days seem endless, and between the beach, social gatherings, and impromptu snacks, opportunities to eat multiply without any real hunger driving them. When that structure disappears, the body’s internal signals get confused, and we end up eating more out of convenience than out of necessity. The snack within reach, the dessert everyone ordered, the appetizer that drags on. None of this is true hunger, but the body, without the anchor of a schedule, can no longer clearly distinguish one from the other.