Some people say that your appetite actually decreases in the summer months because you spend more time in warm weather. While you might've spent all winter hibernating and cooking stew, in the summer, you tend to just eat less and do more. But, is that just a side effect of having a busy summer schedule, or is there a scientific reason why this happens? Well, maybe both.
Research from way back in the '90s points to a concept called "thermoregulation," or body heat regulation, to explain your fluctuating appetite. On an incredibly basic level, we know that eating food provides energy. With this energy, we can create heat to help regulate our body temperature. In cold weather, some hypothesise that you increase your food intake because your body needs to make more heat. And, on the flip side, when it's warmer outside, you need to make less heat, so you theoretically turn to less food.
But this only tells half of the story — after all, we don't exist in a vacuum, especially in the summertime. There are tons of other outside factors that can affect your appetite, cravings, and feelings of satiety. For example, you might crave lighter, more hydrating foods over heavier or saltier ones in the summer because they taste refreshing when you're hanging outside in the sun. Or, you might not have time to eat a full meal when you're on a summer hike or sitting on the beach all day, so you opt for a few smaller meals over larger ones. On top of this, you might receive lots of messaging from diet culture telling you that you need to be eating lighter or less food in general in the summer. (Which, quick reminder, is absolute B.S.)
While a little bit of a reduced appetite might be somewhat expected in the heat, in some cases, it can be a sign of something more serious. People who experience seasonal affective disorder, aka SAD, in the summer (totally a thing) might notice that they have a decreased appetite as well as trouble sleeping, weight gain, and anxiety. Heat illness or stroke is another condition that's marked by change in appetite. If you've been exercising in the extreme heat, that can put you at an increased risk of developing heat stroke, so you shouldn't discount those symptoms.
For all of these various reasons, it's extra-important that you listen to your body's natural hunger cues in the summertime, and ensure that you're getting enough macronutrients to suit your needs. Remembering to hydrate is also key to keeping your body temperature in check and replenishing fluids you lose from sweat. After all, your body is going to need energy to check off all your fun summer plans.