Cardiff expert says climate change is affecting people’s routines and food habits. But did you know it is also making people overweight?
The sun blazes, and pavements shimmer as people retreat indoors to escape the unbearable heat. Rather than cooking in a hot and stuffy kitchen, people order takeaway and sip ice-cold drinks for relief and comfort in sugary refreshments. When summer arrives in the UK, this scene becomes a familiar reality. Slowly, the fat settles in without notice.
The traditional narrative around obesity often focuses on personal responsibility and individual lifestyle choices. However, one research suggests that climate change also contributes to this escalating issue.
A research from the Lancet outlines the challenges posed by obesity and climate change, heatwaves and rising temperatures contribute to obesity by increasing reliance on ultra-processed foods and reducing physical activity.
“People underestimate how environmental factors shape our behaviors,” said Dr Pan He, a lecturer at Cardiff University’s School of Earth and Environmental Sciences. “In colder weather, people crave warm, hearty meals, whereas in hot weather, they might opt for sweetened drinks or takeaways instead of cooking.”
The UK experienced record-breaking weather in 2024, marking its fifth warmest winter on record. Since 1961, temperatures of 34.8°C or above have been recorded only 11 times in the UK, six of those instances occurring in the last decade.
Dr. Michele Cecchini, a senior health economist at the OECD, stated that the British craving for sugary drinks during hot days exacerbates the obesity issue. The average consumption in the UK is 78 litres of sugary fizzy drinks per person, which worsens the obesity problem, compared to 61 litres in the Netherlands, 58 litres in Switzerland, and 34 litres in Italy.
“The logic behind that is that in hotter weather, you may want to have more drinks or like more, frozen things, just to cool you down,” said Dr. He. “So that is why we have observed an increase in sugar intake when the weather gets hotter.”
However, unhealthy diet is not the only result brought by the rising temperature. Extremely hot weather often discourages outdoor exercise, leading to reduced movement and long-term weight gain.
The Global Obesity Federation highlights that 36 percent of British adults engage in insufficient physical activity, making us less active than many of our European neighbours. The uncertainty climate in the UK makes this figure even worse.
After noticing the heatwave impact on public health, Peter Frost, an Urban Green Infrastructure Advisor, says that Excessive heat also reduces comfort and disrupts outdoor activities, which are associated with long-term health benefits.
However, the impact extends far beyond individual health concerns, posing a serious financial burden on healthcare systems. Simon Stevens, the NHS chief executive, has warned that obesity could threaten the NHS’s financial stability.
According to the World Obesity Forum, the cost of treating obesity-related illnesses in the UK is projected to rise from £15 billion to £24 billion per year by 2025 unless effective action is taken. This issue is not unique to the UK, countries struggling with obesity are bracing for soaring healthcare costs that may soon become unaffordable for the majority.
This heavy financial cost is due to excess weight, which is a risk factor in an array of chronic health conditions, including Type 2 diabetes, cardiovascular diseases, respiratory diseases, musculoskeletal disorders, several types of cancer and depression. Around 2.8 million people worldwide die each year due to being overweight or obese.
“Tackling obesity requires a multi-faceted approach that includes climate adaptation,” said Dr. He. Fortunately, the UK government has implemented several policies to tackle the crisis.
One of the most significant interventions is the Soft Drinks Industry Levy, commonly known as the sugar tax. In addition, the government introduced restrictions on junk food advertising, particularly targeting children.
The Welsh government plans to introduce regulations in March 2026 that will ban multi-buy offers on unhealthy snacks and prohibit supermarkets from displaying such products near tills or on their website homepages.
“The UK government has been discussing policies to restrict unhealthy snacks. There have been sugar taxes, but people still consume high-sugar products,“ Said Dr. He. “The government needs better communication with the public to explain why these policies are necessary.”