Lizzy Davis, Ph.D., RDN
Photography by Lexi CoonAs scorching heat waves continue to sweep the nation, Lizzy Davis, Ph.D., assistant professor and dietitian education program director at the University of Alabama at Birmingham Department of Nutrition Sciences, explains the physiological mechanisms behind decreased appetite in hot weather and offers valuable insights into optimal nutrition during extreme heat.
The hypothalamus, a critical part of the brain, plays a vital role in regulating both body temperature and hunger/satiety. Davis explains that, when the hypothalamus is engaged in temperature regulation, the focus on hunger diminishes. This biological mechanism reduces the urge to eat and subsequently minimizes the heat generated from digestion, complementing the body’s efforts to maintain a cool internal environment.
“While the hypothalamus works diligently to regulate body temperature, it also suppresses appetite,” Davis said. “This means that, during hot weather, our bodies naturally tend to eat less, as the hypothalamus prioritizes temperature control. It’s an important adaptive response to reduce heat production from digestion while managing body temperature.”
Addressing the specific needs of athletes or exercising in extreme heat, Davis advises paying attention to sodium intake levels. During intense workouts on hot days, individuals may experience accelerated sodium loss through sweat. To counteract this, athletes should consider slightly increasing their sodium intake, particularly before they start sweating. Adequate preparation becomes crucial to maintain proper electrolyte balance and enhance performance.
When it comes to general nutrition in hot weather, Davis recommends incorporating hydrating foods with high water content into daily diets. Water-rich options such as melons (cantaloupe, watermelon), citrus fruits and cucumbers serve as excellent choices to stay hydrated and refreshed.
However, caution must be exercised regarding certain food choices. Additionally, it is important to avoid diuretic substances like caffeine (iced coffee or iced tea) and alcohol, which can contribute to dehydration by increasing urine production. Regular consumption of water throughout the day is highly encouraged to replenish fluids and maintain adequate hydration levels.
“People also may want to avoid heavy meals as they add heat to your body,” Davis said.
She emphasizes that water requirements are not one-size-fits-all and vary depending on various factors such as sex, physical activity levels, underlying medical conditions, body size and age.
“Focus on your thirst cues,” she said. “When you’re thirsty, drink. Make sure to carry around a water bottle so you’re able to do so.”