Obesity has long been associated with chronic illnesses such as heart disease and diabetes. However, a new study published in the Lancet reveals that being overweight can also increase the risk of severe infections caused by viruses, fungi, parasites, and bacteria. This study analyzed data from over 540,000 individuals in the UK and Finland and found that the risk of severe infection rose as body weight increased. These findings highlight the potential impact of excess fat on the body’s ability to combat infections.
The study found that obesity was linked to a higher risk of hospitalization and mortality from various infections, including influenza, COVID-19, pneumonia, HIV, and skin and soft tissue infections. Individuals with higher body mass index (BMI) and waist circumference had a greater risk of severe infection. The research showed that obesity was associated with an estimated 8.6% of infection-related deaths in 2018, 15% in 2021 during the peak of the COVID-19 pandemic, and 10.8% in 2023 after the pandemic’s height.
The study also revealed that obesity had the strongest association with severe skin and soft tissue infections, but the elevated risk was observed across all infection types. Biologically, being overweight can impair lung function and metabolism, making individuals more vulnerable to infections. Chronic inflammation and immune system impairment in obese individuals may also contribute to the increased risk of severe infections.
While the study’s findings suggest an association between obesity and severe infections, further research is needed to establish a clear cause-and-effect relationship. The results underscore the importance of rapid treatment and prevention measures for individuals with obesity, such as vaccines and healthy lifestyle choices. Policy interventions to promote access to affordable healthy food and opportunities for physical activity are crucial in reducing the risk of severe infections and other health issues associated with obesity.
The relationship between weight and health is multifaceted, influenced by biological, social, and environmental factors. It is essential to address stigma, improve healthcare access, and consider individual biology when addressing obesity-related health risks. By supporting science journalism and research, we can better understand the complex relationship between weight and health and promote evidence-based interventions to improve public health.

