When temperatures rise, appetite decreases. Two doctors explain this phenomenon.
- Digesting food and storing its nutrients uses energy, which generates heat. This is one of the reasons why appetite decreases when it’s hot.
- Another hypothesis is that high temperatures reduce the production of ghrelin, a gut hormone that stimulates hunger in the brain.
- Experts recommend favoring foods rich in water when it is hot: melons, lettuce, tomatoes, yogurts, etc.
The summer heat is here. Besides making you sweat more than you’d like to admit, it’s putting a strain on your stomach. So when it’s time to eat, your appetite is nowhere to be found. Dr. Allison Childress, a registered dietitian and nutritionist at Texas Tech University, and Dr. Gordon Fisher of the University of Alabama at Birmingham, explain why we’re less hungry when it’s hot.
Loss of appetite during summer: digestion generates heat
For the expert, the first thing to know is that digesting food and storing its nutrients uses energy. However, this generates heat, which the body seeks to avoid when temperatures are high.
“There are clear differences in caloric intake in cold and warm weather”explains Dr. Allison Childress surveyed by the American Heart Association. “A calorie is a measure of heat. In a cold environment, you have to burn calories to create heat in the body. People living in a hot or warm environment don’t burn as many calories because it warms the body.”
But what mechanisms link external heat and appetite? They are not fully understood at the moment. However, animal research suggests that higher ambient temperatures could reduce the production of ghrelin, a gut hormone that stimulates hunger in the brain.
“Communication between the thermoregulatory processes of the brain and the stomach may play a role in regulating food intake,” says Dr. Gordon Fisher. “But we have not been able to identify an exact mechanism to explain this.”
Heat and nutrition: eating to stay hydrated and healthy
Experts point to another summer phenomenon that occurs at mealtime. As the thermometer rises, the desire for foods that require a lot of digestive effort (and therefore increase heat production) like protein or fiber decreases. But if eating a leg of lamb or a plate of legumes doesn’t appeal to you… you still need to be careful to get the necessary intake of these nutrients. To get the recommended amounts, Dr. Allison Childress suggests eating small amounts of both more frequently throughout the day. Her colleague, for his part, specifies that it is best to avoid high-calorie foods during peaks of heat.
Choose foods rich in water that help you stay hydrated. In fact, they provide at least 20% of the body’s water intake. “Melons, berries, lettuce, celery, tomatoes, cucumbers, gazpachos, granitas and yogurts are just some of the foods that are rich in water and also provide cooling effects.”confirms Dr. Gordon Fisher.
But of course, water is still the best weapon against dehydration. To make it a little more “fun,” experts suggest slipping a few mint leaves, an orange slice, or a cucumber into the bottle. This will flavor the drink without adding sugar or additives. Dr. Allison Childress adds that low-fat milk “can be a good option, because it is a liquid that you can drink cold and also contains a lot of nutrients.”
