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When the heat sets in, the siren (汽笛) song of the ice cream truck fills the air, and lemonade stands appear along sidewalks. These sweet treats are often synonymous (同义的) with summer, and a new study has found that sugar consumption in the U.S. rises noticeably as temperatures climb. The magnitude of such impact is particularly apparent among certain groups of people and raises concerns over the health implications as the climate continues to heat up.

Much of the research on global warming and food has focused on how climate affects the nutritional content of food or how food consumption contributes to greenhouse gas emissions. Pan He, an environmental scientist, hit on the idea to look at the relationship: how rising temperatures affect food consumption. Her team focused on sugar due to its links to diabetes, heart disease and cancer.

The researchers paired temperature data with U.S. household grocery purchases. They found little difference in consumption below 12℃. But between that temperature and 30℃, consumption increased by 0.7g/℃. There was a slowdown above 30℃, which the authors propose could be related to extreme heat suppressing (抑制) appetite.

Most of the overall increase came from sugary drinks like sodas. Frozen desserts such as ice cream made a smaller contribution. There was a slight decrease in the consumption of sugary foods such as cakes or cookies, suggesting people may be replacing other options with iced treats. The increase is concerning because the average recommended daily sugar intake for a 2,400-calorie diet is about 60g—and a single can of soda can have around 40g.

Consumption patterns varied, though. Men consumed more sugary drinks than women. Also, the amount of added sugar consumed during hot weather was several times higher for low-income families than for wealthy ones. Lower-income households are less likely to have access to air conditioning, making them more reliant on sugary drinks to cool down. Outdoor workers and less-educated families also showed higher sugar consumption. There were additional differences, with White Americans having the highest added sugar effect, while Asian Americans showed no significant change. This suggests climate change may widen existing nutritional inequalities and unintentionally worsen diet-related health risks.

The researchers projected that, without intervention, sugar consumption in the U.S. would keep rising with warming. Solutions could include nutritional education, clearer sugar labeling and an added sugar tax. Other measures — like ensuring accessible drinking water and breaks at outdoor workplaces — could cut sugary drink consumption and reduce heat-related illness risks.

Alice Lichtenstein, a nutrition scientist not involved in the study, urges more research into how the accessibility and pricing of sugary drinks compare with those of water for disadvantaged groups. “We need to better understand the behavioral forces behind negative health decisions like increased sugary drink consumption in hot weather,” she says, “and use this to design strategies to lessen these behaviors.”