With the arrival of summer, appetite often tends to decrease and, when we are hungry, we prefer cold dishes, fresh fruit and light foods.
This loss of appetite has very specific physiological bases. We explore the topic further with Dr. Silvia Giugliano , a nutritional biologist at Humanitas Medical Care.
Why do we feel less hungry in the heat?
When temperatures rise, our bodies activate a series of mechanisms to maintain a stable internal temperature. The digestion process requires energy expenditure and generates heat.
Protein-rich foods, in particular, have a greater thermic effect and raise body temperature more than other foods during digestion. For this reason, the body unconsciously tends to reduce calorie intake during periods of intense heat.
Dehydration also affects appetite . When you sweat a lot, you lose fluids and minerals. If these aren’t replaced, the concentration of certain substances in the blood, such as proteins and minerals, increases. The risk is that of entering a vicious cycle: the less you eat, the less fluids you consume through food, further aggravating dehydration and, consequently, loss of appetite.
Additionally, high temperatures can affect the levels of some hormones that regulate appetite, such as leptin and ghrelin, thus contributing to a decrease in appetite.
Finally, it is also good to remember heat stroke, one of the main symptoms of which is loss of appetite, along with:
- high fever
- tachycardia
- nausea
- mental confusion .
How to beat the heat?
The first remedy for limiting the effects of heat on appetite is to maintain good hydration. Drinking 1.5–2 liters of water a day is a useful guideline, but requirements vary based on age, physical activity, and time spent outdoors. On average, on the hottest days, people lose up to 2.5 liters of fluids a day.
The elderly and children are particularly vulnerable: the former because thirst decreases with age, the latter because children, especially those who are very active, tend to sweat a lot. It’s therefore helpful to spread your water intake throughout the day, even with small practical measures, such as keeping a pre-filled bottle handy in the morning.
In addition to fluids, water-rich foods also help maintain fluid balance. Fresh fruits and vegetables such as watermelon, cantaloupe, cucumbers, lettuce, and tomatoes can provide up to 30% of your daily fluid requirement.
Supplementing with foods rich in minerals such as potassium and magnesium —found in fruits, fresh vegetables, and legumes—helps maintain electrolyte balance, especially during periods of increased sweating.
In some specific cases, such as for athletes or those who work outdoors for long periods, it may be helpful to use mineral-containing drinks to replenish electrolytes lost through sweat. In any case, it’s best to consult your doctor.
Even intense physical activity during very hot days can increase the risk of dehydration and affect appetite. It’s therefore important to monitor hydration, especially during prolonged physical exertion.
What to eat when it’s hot?
During warmer periods, it’s advisable to consume light , frequent, and well-spaced meals , adding a mid-morning and afternoon snack, without increasing the overall amount of food consumed. This helps maintain stable energy levels and avoid burdening digestion.
Pasta, rice, or spelt salads, enriched with vegetables and legumes , are an excellent choice for a balanced nutrient intake. Legumes, in particular, lend themselves to cold preparations and can also be used in summer soups or complete salads.
Among protein sources, it’s best to favor fish and eggs , which are more easily digested than red meat. Fresh dairy products are also valuable allies: they provide protein and calcium and are easily digested. However, it’s important to balance your intake and favor lower-fat cheeses, such as ricotta.
Even in the hottest periods, it’s important to ensure adequate protein intake to maintain muscle mass and support immune function. Light protein sources, such as fish, eggs, and fresh dairy products, can be a good choice.
Even if your appetite decreases, it is essential to maintain a varied and balanced diet to ensure you get all the essential nutrients.
What to avoid?
In summer, it’s advisable to reduce your consumption of foods high in salt and saturated fats , such as cured meats and fatty, aged cheeses, because they increase water retention and the sensation of thirst, increasing the risk of dehydration. The same goes for red meats, which are more difficult to digest.
Also be wary of seemingly “refreshing” foods, such as ice cream, popsicles, and sugary cold drinks. The relief they offer is only temporary: digesting the calories in these foods can contribute to an increase in body temperature, precisely because of their thermic effect.
This doesn’t mean completely eliminating protein-rich or high-calorie foods: the goal is to find a balance: stay hydrated, avoid overly processed foods, and maintain a varied and complete diet. Heat can reduce appetite, but it shouldn’t compromise your intake of essential nutrients.
Skipping meals can worsen dehydration and lead to low blood sugar, which in turn can worsen feelings of fatigue and loss of appetite. Spreading your meals evenly helps keep blood sugar levels stable.
