By Lizzie Streit, MS, RDN, LD 

Longer days and schedule changes may throw off your eating routine in the summer, but did you know that there’s also a scientific reason for decreased appetite in warm weather? 

If you tend to feel less hungry in the summer, there’s likely a combination of social and physiological factors at play. 

Thermoregulation and Appetite 

The idea that hotter temperatures lead to decreased appetite stems from the scientific concept of thermoregulation. 

Thermoregulation refers to the ability of humans to maintain their body temperature even when external temperatures fluctuate. Food provides the body with calories, which in turn can be burned to heat the body and maintain thermoregulation (1, 2). 

So, theoretically, people need less food in warmer weather to produce heat and maintain internal temperature than they would in colder months. As a result, appetite may be suppressed in the summer (2). 

Thermoregulation may be also the reason that you crave “lighter” foods in the summer, such as fruits and vegetables, that may not produce as much heat in the body as heavier meats and fats.  

Finally, fruits and vegetables have a high water content and taste refreshing on hot summer days, especially if you’ve been sweating.  

Other Factors that Influence Appetite 

In addition, a number of social and lifestyle factors can impact appetite in the summer.  

For one, you may spend more time socializing with friends, exercising, or doing yard work in the summer, and therefore have a less structured eating schedule. You may eat fewer meals and snacks on days when you are otherwise occupied. 

Exercising in the heat may also suppress appetite, although this is not always a natural or healthy reaction to increased activity. If you notice a drastic loss of appetite and feel fatigued after working out on a hot day, you may be dehydrated or at risk for heat stroke. 

The Bottom Line 

Overall, it’s usually normal to feel less hungry in the summer. But you’ll want to be sure that you’re still getting enough calories and fluids.  

 If you’re struggling to meet your nutrition needs in the summer, try eating more frequent, smaller meals throughout the day and incorporating hydrating foods, such as cucumbers, watermelon, zucchini, pineapple, tomatoes, gazpacho, and smoothies. 

 Note from Healthy For Life Meals: Too hot to cook? Let us do the work for you! Get started with one of our nutritionally complete meal plans today.