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Research presented at the European Congress on Obesity suggests current Body Mass Index (BMI) metrics label healthy athletes as overweight or obese, prompting a call for updated, sport-specific guidelines.
December 15, 2025
MALAGA, Spain — For decades, Body Mass Index (BMI) has served as the global standard for assessing weight-related health risks. However, new research presented this week at the European Congress on Obesity (ECO 2025) confirms what sports scientists have long suspected: for male athletes, the standard BMI scale is fundamentally flawed.
A team of researchers from the University of Verona, Italy, and the University of Modena and Reggio Emilia has revealed that traditional BMI calculations misclassify a staggering number of male athletes as overweight or obese. The study found that while BMI flagged nearly 28% of participants as having excess weight, advanced body composition scanning revealed that less than 4% actually carried unhealthy levels of body fat.
The findings, led by Professor Marwan El Ghoch, challenge the “one-size-fits-all” approach to health screening in sports and propose new, higher BMI thresholds that accurately reflect the physiology of athletic men.
The Muscle Mass Misconception
The core of the problem lies in the simplicity of the BMI calculation. By dividing a person’s weight in kilograms by the square of their height in meters, BMI generates a score that does not distinguish between muscle tissue and adipose tissue (fat).
“BMI doesn’t distinguish between body fat and lean mass, which includes muscle,” explained Professor El Ghoch, the study’s lead author. “As a result, a muscular athlete with low body fat can be wrongly classified as living with overweight or obesity.”
In the study, researchers analyzed 622 male athletes involved in various sports, including soccer, rugby, basketball, and karate. They compared the athletes’ BMI classifications against results from Dual X-ray Absorptiometry (DXA) scans—the “gold standard” for measuring body composition.
Key Findings by the Numbers:
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Standard BMI Assessment: Under current World Health Organization (WHO) guidelines (where ≥25 kg/m² is overweight and ≥30 kg/m² is obese), 27.5% of the athletes were classified as overweight or obese.
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DXA Body Fat Assessment: When measuring actual body fat percentage, only 3.9% of the same group met the criteria for being overweight or obese.
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The Discrepancy: The standard BMI calculation generated a “false positive” rate of over 23% for excess weight in this population.
Proposed New Standards
To bridge this gap, the research team used statistical modeling to identify new BMI cut-off points that align with healthy body fat percentages in male athletes.
The study proposes shifting the thresholds significantly:
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Overweight Threshold: Raise from 25.0 to 28.2 kg/m².
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Obesity Threshold: Raise from 30.0 to 33.7 kg/m².
“This demonstrates that the current BMI cut-off points are clearly flawed in determining weight status in athletes,” said El Ghoch. “Many were misclassified… where in reality, very few had body fat levels in this range.”
Professor Chiara Milanese of the University of Verona, a co-author of the study, noted that while DXA scans are superior, they are expensive and rarely available in local sports clubs. “In its absence, we encourage sports organizations and committees to adopt the new BMI classification system,” Milanese stated. “BMI could be a highly useful tool… with the new cut-offs.”
Expert Perspectives: Beyond the Numbers
The limitations of BMI are well-documented in the medical community, yet the metric persists due to its ease of use. Dr. Céline Gounder, a medical contributor for CBS News and an expert in infectious diseases and public health, has previously highlighted this disconnect.
“BMI is really looking at how much do you weigh relative to your height, but not every six-foot man with the same weight is obese versus healthy,” Gounder noted in recent commentary regarding obesity diagnostics. The failure to account for metabolic health and muscle mass can lead to “over-diagnosis” in fit populations, potentially triggering unnecessary medical interventions or psychological stress for athletes told they need to lose weight.
Furthermore, a recent meta-analysis published in the British Journal of Sports Medicine underscores that cardiorespiratory fitness (CRF) is often a far stronger predictor of mortality than BMI alone. For athletes, high muscle mass and cardiovascular fitness offer protective health benefits that a simple weight-to-height ratio ignores.
Implications for Public Health and Athletics
The adoption of these new cut-offs could have immediate practical applications for sports medicine physicians, coaches, and athletic trainers.
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Improved Screening: By using the adjusted 28.2 kg/m² threshold, staff can screen for health risks without alarming athletes who are simply muscular.
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Mental Health: Reducing misclassification helps prevent body image issues and disordered eating patterns, which can be triggered when lean athletes are told they are “overweight.”
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Resource Allocation: Medical teams can focus weight-management resources on the small percentage of athletes who genuinely have excess body fat (the ~4% identified in the study) rather than the large group misidentified by standard BMI.
Limitations and Future Research
While the study offers a crucial update for male athletes, experts caution that these specific numbers cannot be universally applied. The research focused exclusively on male subjects; female athletes, who have different essential body fat requirements and muscle distribution patterns, require their own specific study to establish appropriate cut-offs. Additionally, the “athlete” category varies widely—the body composition of a marathon runner differs vastly from that of a rugby prop, suggesting that sport-specific nuances may still need to be considered.
Conclusion
As the medical community moves toward “precision medicine,” tools like the BMI must evolve. This study serves as a pivotal step in acknowledging that high weight does not always equal poor health. For the male athlete, a BMI of 27 may not be a warning sign, but rather a badge of hard-earned muscle.
Medical Disclaimer:
This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.
References
Study Citation:
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El Ghoch, M., Milanese, C., et al. (2025). “Traditional BMI cut-offs overestimate overweight and obesity in male athletes.” Presented at the 32nd European Congress on Obesity (ECO 2025), Malaga, Spain, May 11-14, 2025.
