As temperatures rise, many people notice a natural drop in appetite. The body adjusts its internal processes to prevent overheating, reducing the desire for heavy meals. Dr Lucy Hooper, private GP and co-founder of Coyne Medical in London, explains the science behind this and offers practical advice for staying nourished and hydrated during hot spells.
Why Heat Suppresses Hunger
Dr Hooper points to several physiological mechanisms. The brain acts like a thermometer: special nerve cells detect body temperature and send chemical messages to reduce appetite when the body gets too warm. Additionally, digestion generates internal heat, so the body limits large meals to avoid raising core temperature further.
Blood flow is redirected from the gut to the skin to facilitate sweating and cooling. This diversion slows digestion and can cause mild nausea. Hormonal changes also play a role; gut hormones, similar to those targeted by GLP-1 medications like Mounjaro, can reduce appetite, especially during exercise in hot weather.
Who Is Most Affected?
Certain groups are more sensitive to heat and appetite changes. The young and elderly are more vulnerable due to biological differences, as are people with pre-existing conditions such as heart and lung diseases. These individuals should be particularly mindful of their food and fluid intake during heatwaves.
Practical Tips for Eating in Heat
Dr Hooper recommends adjusting meal times to cooler parts of the day, such as early morning or late evening, to maintain energy levels. Staying hydrated is crucial: sip water regularly rather than waiting until thirsty. Dark urine or reduced urination are clear signs that more fluids are needed.
Choosing cooler foods can help. Salads, watermelon, and ice lollies are better options than hot pasta or spicy curry, which can make you feel worse. However, it's essential to include carbohydrates and protein for energy. If food intake is inadequate, multivitamins from a pharmacy may be helpful.
If you experience persistent weakness, inability to eat or drink enough, or reduced urination, consult a doctor. These symptoms could indicate dehydration or other heat-related issues requiring medical attention.
