The scale might show the same number, but not all body fat is created equal. New research involving over 438,000 people reveals that visceral fat, the deep abdominal fat surrounding the organs, plays a significantly different role in health and mortality than the fat that can be pinched under the skin (subcutaneous fat). Even more surprising: having too little visceral fat can be just as dangerous as having too much, particularly for men under 50 and women over 60 (Yu et al., 2023). This discovery challenges everything we thought we knew about maintaining a healthy weight.
Current understanding challenges weight-loss myths
Traditional weight management focuses on total body mass, but research from the UK Biobank study shows this approach misses critical health markers. Among 21,241 participants studied, visceral adipose tissue volume emerged as the strongest predictor of cardiovascular ageing, more potent than body mass index (BMI) alone (Losev et al., 2025). The most striking finding was that having extremely low visceral fat increases the risk of mortality. Men in the lowest quintile of visceral fat showed a 30% higher risk of death before age 50, while women over 60 with minimal visceral fat faced a 16% increased mortality risk (Yu et al., 2023). This J-shaped relationship suggests an optimal middle ground exists. Dr Declan O’Regan’s team found that visceral adipose tissue, muscle adipose tissue infiltration, liver fat fraction, and total abdominal adipose tissue were associated with adverse changes in cardiovascular age-delta for both sexes (Losev et al., 2025). However, the relationship is not simply ‘less is better’, it is about finding the right balance.
The science behind visceral fat function
Visceral fat serves essential biological functions beyond energy storage. Unlike subcutaneous fat, visceral adipose tissue acts as a metabolically active organ system, secreting hormones and cytokines that regulate diverse biological processes (Yu et al., 2023). Further research shows visceral fat provides crucial support and protection for internal organs while playing vital roles in insulin resistance, lipolysis, and glucose uptake (Yu et al., 2023). The tissue synthesises bioactive mediators called adipokines, some of which are protective, such as adiponectin and omentin, while others are inflammatory, including leptin and resistin. A study of 471 middle-aged and elderly participants found that pericardial fat, visceral fat around the heart, correlates most strongly with other visceral fat deposits rather than subcutaneous fat. This suggests visceral fat depots share common developmental origins and functions but also increase cardiovascular disease risk (Ni et al., 2021). Sex differences add complexity. Women typically store more subcutaneous fat, while men accumulate more visceral fat. In the UK Biobank analysis, males predominantly had greater volumes of visceral fat (5.1 ± 2.3 L vs. 2.8 ± 1.5 L) compared to females (Losev et al., 2025).
Understanding visceral fat risks
While extremely low visceral fat poses unexpected dangers, excess visceral fat creates well-documented health problems. The UK Biobank study found that participants in the highest visceral fat quintile showed increased cardiovascular ageing equivalent to adding years to their biological age (Losev et al., 2025). Visceral fat promotes abnormal secretion of inflammatory cytokines and bioactive peptides that accelerate ageing in multiple organ systems. The research revealed glycoprotein acetyls, which are stable markers of cumulative inflammation over several years, were associated with accelerated ageing (Losev et al., 2025). However, the risks are not universal. Age dramatically modifies these relationships. Among men under 50, both very high and very low visceral fat increased mortality risk. For older men, the relationship became more straightforward; higher visceral fat consistently increased death risk (Yu et al., 2023). Women showed opposite patterns, with linear relationships in younger years but J-shaped curves after age 60.
Personal impacts
These findings suggest there must be an adjustment to personal health strategies. Traditional calorie-restriction approaches that dramatically reduce all body fat may inadvertently increase health risks. The research suggests that maintaining moderate levels of visceral fat provides optimal protection. For men under 50, aggressive fat loss that drops visceral fat to extremely low levels increases mortality risk by 30%. This means young men pursuing ultra-lean physiques through extreme dieting or intensive training may compromise long-term health (Yu et al., 2023). The data shows moderate visceral fat levels, roughly the third quintile in population distributions, provide the safest health outcomes. Women face different considerations. Before age 60, maintaining lower visceral fat generally supports health. However, after menopause, the relationship changes dramatically. Women over 60 with minimal visceral fat show 18% higher mortality risk, suggesting hormonal changes alter fat’s protective functions (Yu et al., 2023). The research also reveals that gynoid fat distribution, fat stored in the hips and thighs, provides cardiovascular protection specifically for pre-menopausal women. This gynoid fat was significantly associated with beneficial changes in cardiovascular age-delta in pre-menopausal females but showed no protective effect after menopause (Losev et al., 2025).
Influences on healthcare
These discoveries demand fundamental shifts in medical screening and treatment approaches. Current health assessments rely heavily on BMI calculations, but the UK Biobank analysis found BMI was a weak predictor of age-delta in either sex compared to visceral fat measurements (Losev et al., 2025). Healthcare systems worldwide may need to adopt body composition analysis rather than simple weight measurements. The research showed that 31% of women classified as overweight by BMI fell into normal ranges for whole-body fat mass, while 11% of overweight men were reclassified as having normal fat levels (Losev et al., 2025). Economic implications extend beyond individual health costs. Accurate risk assessment could prevent unnecessary interventions while identifying high-risk individuals currently missed by BMI screening. Ni et al. (2021) found strong correlations between pericardial fat and cardiovascular disease markers, suggesting targeted imaging could improve early detection. Population health strategies must account for sex and age differences in optimal fat distribution. Public health campaigns promoting extreme fat reduction may inadvertently harm specific demographic groups, particularly young men and older women.
What this means
Future medical practice will likely emphasise body composition over total weight. Advanced imaging techniques that measure visceral fat distribution are becoming more accessible, potentially replacing routine BMI calculations in clinical settings. The research identifies several emerging therapeutic targets. GLP-1 receptor agonists, currently used for diabetes treatment, substantially reduce visceral and liver fat while suppressing pro-inflammatory mediators of ageing (Losev et al., 2025). These medications may represent first-generation treatments specifically designed to target unhealthy fat distribution. Age-specific guidelines appear necessary. The data suggests health recommendations should differ based on life stage, moderate fat restriction for middle-aged adults, but avoiding extreme reduction in young men and older women. This personalised approach represents a significant departure from current one-size-fits-all dietary advice. Long-term research will likely explore optimal visceral fat ranges for different populations. The current studies provide broad quintile ranges, but future work may establish precise targets based on individual characteristics, including genetics, hormonal status, and metabolic health markers
References
Losev, V., Lu, C., Tahasildar, S., Senevirathne, D. S., Inglese, P., Bai, W., King, A. P., Shah, M., de Marvao, A., & O’Regan, D. P. (2025). Sex-specific body fat distribution predicts cardiovascular ageing. European Heart Journal, 00, 1–13. https://doi.org/10.1093/eurheartj/ehaf553
Ni, X., Jiao, L., Zhang, Y., Xu, J., Zhang, Y., Zhang, X., Du, Y., Sun, Z., & Wang, S. (2021). Correlation between the distribution of abdominal, pericardial, and subcutaneous fat and muscle and age and gender in a middle-aged and elderly population. Diabetes, Metabolic Syndrome and Obesity, 14, 2201–2208. https://doi.org/10.2147/DMSO.S299171
Yu, B., Sun, Y., Du, X., Zhang, H., Chen, C., Tan, X., Yang, Z., Lu, Y., & Wang, N. (2023). Age-specific and sex-specific associations of visceral adipose tissue mass and fat-to-muscle mass ratio with mortality risk. Journal of Cachexia, Sarcopenia and Muscle, 14, 406-417. https://doi.org/10.1002/jcsm.13142