A NEW analysis of U.S. population data suggests that where fat is stored in the body, not just how much, can significantly affect the risk of developing type 2 diabetes (T2D). Researchers found that higher lower-body fat, particularly in the legs, may protect against diabetes, while visceral fat around the abdomen increases risk, especially in men.
The study, using data from the 2011–2018 cycles of the National Health and Nutrition Examination Survey (NHANES), examined adults matched for body mass index (BMI) to focus on differences in regional fat distribution rather than total body weight. BMI alone often fails to explain why 30%–40% of diabetes cases occur in people with a healthy weight, prompting the need to explore fat distribution and its metabolic effects.
Participants were classified as high-risk for T2D if they had elevated fasting blood glucose, abnormal glucose tolerance, or a physician’s diagnosis of diabetes or prediabetes. Body composition was measured using dual-energy X-ray absorptiometry (DXA), a precise method to quantify regional fat and muscle mass.
Lower-Body Fat Linked to Reduced Diabetes Risk in Men
The findings revealed that individuals at high risk for diabetes had significantly less lower-limb fat than healthy controls. Analysis indicated that more lower-body fat acted as a protective factor against both diabetes and insulin resistance. In contrast, visceral fat around the abdomen was strongly associated with increased diabetes risk. Interestingly, these effects were most pronounced in men, highlighting a sex-specific pattern in how fat distribution influences metabolic health.
The study also explored mechanisms behind this protective effect, finding that about 36% of the benefit of lower-limb fat on diabetes risk was mediated by improved insulin sensitivity. This suggests that lower-body fat may help regulate blood sugar levels by enhancing the body’s ability to respond to insulin, while excess visceral fat impairs this process.
Implications for Future Research and Clinical Practice
Researchers emphasise that these results challenge the notion that BMI alone is sufficient to assess diabetes risk. Instead, regional fat distribution plays a crucial role in metabolic health, particularly in men, and could inform more personalised prevention strategies.
The study highlights the importance of looking beyond total weight when evaluating diabetes risk and suggests that maintaining healthy lower-body fat may offer a protective advantage. These findings could influence future guidelines for risk assessment and targeted interventions in both men and women.
Reference
Wang Q et al. Sex-specific protective role of lower-body fat in type 2 diabetes: mediation through insulin resistance in a BMI-matched population. BMJ Open Diabetes Res Care. 2025;13(6):e005397. doi:10.1136/bmjdrc-2023-005397.
