As temperatures rise and summer routines settle, many instinctively turn to lighter meals. Salads, fruit bowls, and smaller portions often take center stage, driven by appetite and habit. However, the seasonal shift does not necessarily reflect the body’s needs. Colin Robertson, a nutrition scientist, asserts that humans do not need significantly fewer calories during summer in typical circumstances. This idea is largely a misconception.
Research indicates that warmer temperatures can suppress appetite, creating the impression that less food is required. One study revealed that food intake dropped by around a quarter in summer compared to winter, despite no increase in energy expenditure. Robertson explains, ‘The decrease in summer intake is driven by appetite suppression rather than actual reductions in metabolic requirements.’
This appetite drop is not solely psychological. Heat affects the body in ways that directly reduce hunger, activating pathways in the brain that lower the desire to eat. It also alters hormone levels linked to appetite. Mild dehydration and the body’s efforts to regulate temperature can further blunt hunger signals.
“Heat can suppress appetite,” registered dietitian Kylie King told Newsweek. “Eating less can feel natural in the moment, but it’s usually a temporary appetite response, not a meaningful drop in energy needs.”
This mismatch often leads to a recognizable pattern: eating little during the day, then feeling hungrier later. King notes this can lead to overeating at night, especially with disrupted sleep in hot weather.
Summer foods also play a role. Salads, fruit, and other light meals dominate seasonal menus, partly due to their refreshing nature in the heat. Robertson explains that cultural influences affect preferences: ‘People consistently prefer cold foods in warm conditions, even though hot meals tend to increase satiety hormones more effectively.’
Long-standing messaging around ‘summer bodies’ and lighter eating habits adds another layer. King points out the mindset of associating summer with restriction. She cautions that eating ‘lighter’ all day, like skipping breakfast or opting for small salads, can backfire. If appetite catches up at night, it may lead to eating more than if adequately fueled earlier.
Experts warn of risks associated with significantly cutting food intake, especially for active people. When heat, high activity levels, and low food intake overlap, energy, recovery, and hydration can be affected. King notes that protein often drops first, impacting muscle maintenance and recovery.
Robertson highlights broader nutritional consequences: when overall intake falls, meeting essential vitamin and mineral needs can be challenging, especially as heat and sweating increase nutrient losses. Active individuals may be particularly at risk.
Hydration complicates the picture. Experts agree relying on thirst alone is insufficient in hot weather. Robertson points out, ‘People typically under-drink when relying on thirst alone,’ suggesting hydration should be planned throughout the day. Hydration influences appetite, as dehydration can suppress hunger, increasing the risk of under-eating. King advises maintaining structured meals even with low appetite. ‘Don’t wait until you feel hungry to eat.’
‘Light’ does not mean less. Balanced meals with protein, carbohydrates, healthy fats, and hydrating fruits or vegetables provide sufficient energy, feeling suitable for warm weather.
Experts emphasize the biggest myth about summer eating is the notion that less food is healthier. Robertson states, ‘Eating less does not necessarily mean eating better.’ Appetite changes in the heat are physiological responses, not indications of fewer nutrient needs. The key is not to eat less, but to eat differently, maintaining nutrition while adapting to warmer weather.