When the weather turns hot, it can be hard to say no to a delicious ice cream or a refreshing cold drink.
But scientists now warn that our summer indulgences could be part of a much more serious problem.
According to new research, our warming climate threatens to make us all obese.
Researchers found that, as the weather gets warmer, people reach for sugar-rich foods like fizzy drinks, juice, and frozen desserts.
Hot weather increases sweating and therefore how much people need to drink to stay hydrated.
But rather than opting for healthy water, researchers found that people often go with an unhealthy sugary alternative.
Between 12°C and 30°C (54-86°F), people consume 0.7 grams more sugar every day for each degree warmer it gets.
That means people may eat over two teaspoons more sugar when it’s 25°C (77°F), compared to when it is 12°C (54°F).
Scientists have found that climate change could make us all obese as people turn to sugar treats like fizzy drinks and ice cream in warmer weather (stock image)
Previous studies have shown that the warming climate is likely to have a serious impact on public health.
However, scientists’ understanding of how this might affect our diets is much more limited.
Lead researcher Dr Pan He, of Cardiff University, told The Daily Mail that hotter weather drives sugar intake for two main reasons.
She says: ‘First, higher temperature would facilitate metabolism and lead to higher demand of hydration. If one is used to using sweetened beverages to hydrate themselves, then this would become the problem.
‘Second, one may use frozen food and drinks to physically cool down, and many of these products have added sugar, such as frozen yoghurt and ice cream.’
To study this potential connection, in a study published in Nature Climate Change, an international team of researchers collected US household purchasing data from 2004 to 2019.
The researchers then compared the amount of sugar in Americans’ shopping to local weather conditions, including temperature, wind speed, and humidity.
This revealed that there was a strong connection between daily temperature and the quantity of sugar consumed.
The researchers compared 15 years of US household purchasing data against local meteorological conditions. They found that, between 12°C and 30°C (54-86°F), people consume 0.7 grams more sugar every day for each degree warmer it gets
The researchers say that warm weather increases people’s hydration needs. For those who are accustomed to drinking sweetened drinks, this leads to increased sugar consumption. Pictured: Sunbathers on Brighton Beach during the summer heatwave on August 12
However, Dr He says she was surprised to find that this increase was sharpest at relatively mild temperatures.
Dr He says: ‘You don’t even need hot weather for people to take more sugar.’
Sugar consumption steeply increases with temperature between 12°C and 30°C (54-86°F), with a ‘marked escalation in consumption’ occurring at 20°C.
The increase was most rapid between 24°C and 30°C (75-86°F), but sugar consumption continues to climb even at temperatures about 30°C.
If the global heating trend continues, Dr He and her co-authors predict that the average American could consume 2.99 grams more sugar every day by 2095.
It is worth noting that this would be the case for a fairly extreme, but not impossible, heating scenario of 5°C (9°F) above the pre-industrial average.
However, these patterns show that the risks of obesity and other diet-related health conditions are likely to become worse as climate change continues to warm the planet.
As the data suggests, these effects would be most pronounced among the poor and less educated, who already tend to consume more sugar on average.
By 2095, if the climate continues to heat at current rates, the average person might consume up to 2.99 grams of extra sugar every day due to the effects of global warming
This follows the UK’s hottest summer on record, with temperatures hitting an average of 16.1°C (61°F). Scientists say these record-breaking conditions were made 70 times more likely due to climate change
The study found that those with lower levels of education and lower income tend to increase their sugar consumption faster as the heat rises.
As the health impacts of climate change continue to mount, this suggests that it is the least well-off in society who once again bear the brunt of the harm.
Study co-author Dr Duo Chan, of the University of Southampton, told Daily Mail: ‘So far, the health impact of climate change has been described mainly in terms of how extreme heat can cause heat stroke, which occurs on short time scales.
‘On the other end of the spectrum, what we find is the slower, long-term influence of temperature change, acting through diet.’
Although Dr Chan says the results – that people have more sweet drinks when it is hot – were not surprising, the quality of the data was an important step forward.
He says: ‘To me, the main contribution of this work is that it uses new high-resolution purchasing data to quantify this relationship.
‘This provides concrete evidence for an intuitive argument and highlights a neglected perspective on the health burden of climate change.’