Hotter days, different diets: more fruit and water, but also more alcohol and sugary drinks as temperatures rise
Climate change is not only reshaping landscapes and crop yields: it may also be changing what we eat and drink. By linking nearly 1.7 million dietary records from the NutriNet-Santé cohort to daily Météo-France temperatures, the EREN team shows that hot days come with contrasting dietary shifts, some beneficial to health and others not, unevenly distributed by sex and socioeconomic profile. The study is published in The American Journal of Clinical Nutrition.
An under-explored public health issue
Europe is warming faster than the global average and, in France, temperatures could rise by up to 4 °C by 2100 without rapid action toward carbon neutrality. While the direct health effects of heat (heat stroke, cardiovascular and kidney disorders, excess mortality) are well documented, its indirect effects, mediated by behaviour, remain poorly studied. Large-scale research on the link between temperature and diet is scarce: a recent US study of household purchases between 2004 and 2019 found that the added-sugar content of purchased products rose with temperature, more markedly in households with lower income or education.
A study of unprecedented scale
The researchers analysed 1,716,046 24-hour dietary records collected between 2009 and 2023 from 100,851 NutriNet-Santé participants living in mainland France. Each record was linked to the daily maximum temperature recorded at the Météo-France station closest to the participant’s home, among more than 3,000 stations. Six socioeconomic profiles were identified from education, income and occupation: employees, privileged, intermediate, young, disadvantaged and retirees. Associations were estimated with linear mixed models accounting for age, sex, season, energy intake and region, among other factors.
Contrasting shifts as the thermometer rises
Regardless of sex or profile, higher temperatures were associated with greater consumption of fruit, vegetables, water, sweet products, processed meat, alcoholic beverages and sugar-sweetened beverages, whereas consumption of red meat, pulses and dairy products decreased. Between 25°C and 35°C, water intake rose by about 25%. Alcohol intake increased by 11% in men (from 150 to 166 g/d) versus 6% in women (from 101 to 107 g/d). The magnitude of change differed across profiles: sugar-sweetened beverages rose by 29% among young people (from 56 to 72 g/d) and by 24% among employees, compared with 11% among retirees and the disadvantaged; alcohol rose by 14% among employees versus 5% among young people; fruit intake increased by 17% among employees but by only 9% among young people.
Energy intake and overall diet quality scores remained broadly stable. This stability is, however, partly misleading: the scores do not capture alcohol, and the average reflects favourable shifts (fruit, vegetables, water) offsetting unfavourable ones (alcohol, sugar-sweetened beverages). For these two exposures, the risk of cardiometabolic disease and cancer rises continuously with intake, with no clearly identified safe threshold. Even a small upward shift in the distribution of intakes therefore matters for public health. We can observe describe a “nutritional paradox of heat adaptation”, whose unfavourable side could widen diet-related social inequalities in health.
Implications for prevention
These findings support targeted prevention messages once temperatures exceed 25 °C: promoting tap water and seasonal fruit and vegetables, restricting the advertising and promotion of alcohol and sugary products during hot periods, and tailoring messages to different audiences and sociocultural settings. As heat episodes become more frequent and prolonged, these adjustments could shift from seasonal variations to lasting features of dietary habits.
- Kesse-Guyot E, Berlivet J, Meyer E, Julia C, Fezeu LK, Touvier M, Hercberg S, Meirhaeghe A, Baudry J. The relationship between food intake and outdoor temperature in a longitudinal study: a public health perspective in the context of global warming. The American Journal of Clinical Nutrition. 2026;124:101430. https://doi.org/10.1016/j.ajcnut.2026.101430
By Emmanuelle Kesse-Guyot
