New cases of obesity are rising fastest in younger adults in England, a study suggests, because apparently the 20s and 30s are the new 50s for metabolic despair.
Rates of new diagnoses for people in their 30s were nearly 20% higher in 2024-25 than they were in 2019-20, according to the study published in The Lancet. For people in their 20s, new cases jumped by 16%. These increases were higher than in older age groups - although the most common ages for diagnosis remained the 40s and 50s, so the middle-aged can still claim the crown for now.
But experts said the trend towards earlier diagnosis was worrying given obesity increases the risk of illnesses such as diabetes, heart disease and cancer. Because nothing says "young adulthood" like a heightened risk of everything your grandparents have.
Alongside the age-group breakdown, the team also identified significant differences between different ethnic groups - earlier onset of obesity was more common in non-white people - while the areas with the highest levels of deprivation also saw steeper rises. These patterns, when it comes to obesity, are well established, but the acceleration in new cases among younger adults was more unexpected, the researchers said.
Lead researcher Robert Fletcher said while the study did not investigate the causes behind the rise, he felt there were three key factors: a childhood spent marinating in junk food, the pandemic, and the cost of living crisis. "They have been surrounded by unhealthy food in their formative years," he said, noting the proliferation of takeaways and fast food ads. He also cited the stress of pandemic-era parenting and inflation making healthy food feel like a luxury.
Sarah Perman, from the Association of Directors of Public Health, agreed, noting that unhealthy options now dominate "our supermarkets, corner shops and fast food outlets." Research by the Food Foundation has found healthy foods are twice as expensive per calorie than unhealthy foods, which is a pretty good deal if your goal is maximum calories for minimum cash.
Katharine Jenner, of the Obesity Health Alliance, pointed fingers at the digital environment, where younger age groups are more likely to be using food apps and spending time on social media, while the pandemic disrupted physical activity at a "crucial moment."
The team - from the University of Cambridge, British Heart Foundation Data Science Centre and George Institute for Global Health - analysed 55 million adult NHS patient records. Among those aged 30 to 39 there were 24.1 new cases diagnosed per 1,000 people in 2024-25 compared to 20.3 in 2019-20. Among those aged 20 to 29 there were 20.3 new cases per 1,000, up from 17.5 five years earlier. Rates of new cases actually fell in those aged 60-79, possibly because they can afford weight loss drugs or have already been counted.
Overall the proportion of people recorded as obese rose from 26.2% to 30.3% during the period. Prof Sir Michael Marmot described the findings as concerning and "further evidence" of widening inequalities since the pandemic. A Department of Health and Social Care spokesperson said the government was taking "decisive action" on obesity, including new restrictions on junk food advertising and targets on healthy food sales. We'll believe it when we see the salad ads.