A groundbreaking study published on June 26, 2025 in the Annals of Family Medicine has revealed that body fat percentage (BF%) is a significantly better predictor of both all-cause and cardiovascular mortality than the widely used body mass index (BMI), particularly in adults aged 20 to 49. This major shift in understanding could have profound implications for how Thai clinicians and public health officials assess obesity and related health risks across the country.
For decades, BMI has been the routine tool in Thai hospitals and clinics to assess obesity, widely relied upon for health screenings, workplace wellness programs, and even national health surveys. However, BMI, which is calculated using only height and weight, has long been criticized for its inability to distinguish between muscle and fat mass—a limitation now brought sharply into focus by the latest large-scale research. According to the study, unlike BMI, measuring body fat percentage via bioelectrical impedance analysis (BIA)—a technology available at a range of prices and now faster than ever—provides a far more telling indicator of long-term mortality risk.
The research team, led by a professor and vice chair for research at the University of Florida, analyzed data from 4,252 adults participating in the U.S. National Health and Nutrition Examination Survey from 1999-2004. They compared the 15-year mortality risks—both all-cause and cardiovascular—using both BMI and BF%, with the latter measured by BIA. The results were striking: adults with “unhealthy” body fat percentages (defined as ≥27% for men and ≥44% for women) had a 78% increased risk of dying from any cause and were about 2.6 times more likely to die from cardiovascular disease than those with healthy BF%. In contrast, there was no statistically significant link between BMI and mortality outcomes in the same group.
One of the study’s authors, a clinical associate professor and medical director at UF Health Family Medicine, emphasized the reliability and ease of BIA machines, which today produce results in less than a minute—far more accessible and affordable than DEXA scans, which are prohibitively expensive and rarely used in primary care settings. The study’s use of 25-year-old BIA technology, with strong results, further underlines the robustness of their findings and suggests that even current entry-level machines can offer meaningful insights.
The underlying message echoes what many endocrinologists, nutritionists, and researchers in Thailand have noted for years: that high BF%, not just excess weight, drives many of the non-communicable diseases now rising rapidly in the Kingdom—such as heart disease, diabetes, and metabolic syndromes. For example, a prominent member of Thailand’s Obesity Association (position named per protocol) has pointed out in seminars that many Thais with a “normal” BMI nonetheless carry high levels of visceral fat, putting them at risk for silent conditions like fatty liver and hypertension.
The new research thus strengthens calls for Thai health authorities to reconsider screening protocols in schools, workplaces, and hospitals, and to encourage investment in BIA technology. At present, most Thai hospitals track BMI as part of the Ministry of Public Health’s annual health checks, but very few provide BF% as a standard measure. Experts suggest this may soon change, as the study’s lead author predicts BF% will become standard-of-care once consensus definitions for healthy and unhealthy levels are established via larger prospective trials.
The affordability argument is also persuasive for middle-income countries like Thailand. While DEXA scanners cost upwards of 500,000 baht, BIA machines are now available from less than 5,000 baht to over 500,000 baht depending on features—a price range that puts the technology within reach for public hospitals, private clinics, and even some larger community health centers in rural provinces. As one senior official in Thailand’s National Health Security Office has noted (position named per protocol), rapid and accurate body composition assessments could help target public health interventions far more efficiently.
However, the study cautions that there is still no international consensus on cutoffs for healthy BF% by age, gender, and ethnicity. Minimal training is required for interpreting BIA results, but variability remains in how the data is used to inform clinical decision-making. In the Thai context, where genetic, dietary, and lifestyle factors differ from Western populations, further local studies will be vital to define thresholds appropriate for the nation’s diverse population. Similar concerns have been raised in a recent policy paper by the Faculty of Medicine at a leading Bangkok university, which called for large-scale Thai cohort studies to calibrate BF% cutoffs for the local context.
Notably, the latest research brings new urgency to the ongoing debate about the limitations of BMI, which originated in 19th-century Europe and was never intended as a diagnostic tool. As Thailand’s society urbanizes and traditional diets shift, the concept of “thin outside, fat inside” (TOFI) has gained recognition among local health professionals. TOFI individuals—those who appear slim but store excess internal fat—are at high cardiometabolic risk but may be overlooked using BMI alone. This pattern is seen not only in Thailand but also in other Asian populations such as Japan, China, and Singapore, all of which have begun to revise screening guidelines to account for body composition rather than weight alone (Medscape).
The response from the Thai medical community has been measured but positive. An adviser to the Thai Association for the Study of Obesity (position named per protocol), interviewed for this report, said, “This new evidence confirms what we have observed in clinical practice for years: BMI often fails to capture the true risk, especially among our patients who do not appear overweight but have high body fat and metabolic abnormalities.” The adviser added that increased access to BIA could help address Thailand’s growing burden of diabetes and cardiovascular disease—a burden expected to rise further as the population ages.
As for the impact on public health policy, the Ministry of Public Health has previously piloted more advanced body composition measurements in select regional hospitals, but the approach has not yet been scaled nationwide. Some municipal health clinics in Bangkok, Chiang Mai, and Khon Kaen have added BIA screening for high-risk groups. A health program director at the Bangkok Metropolitan Administration (position named per protocol), in a recent statement, noted, “We are closely monitoring global guidelines and will consider incorporating BF% in future city-wide health campaigns if international consensus emerges.”
Looking to the future, greater acceptance of BF% measurement in Thailand could reshape everything from health insurance premiums to school health curriculums. Some private hospitals already advertise full body composition analysis as part of executive health packages, and a handful of weight management clinics in Bangkok use BIA to tailor diet and exercise regimens for clients. Market analysts predict that demand for affordable, user-friendly BIA devices could surge, especially among Thailand’s growing population of health-conscious young adults.
Thais have deep cultural attitudes toward body image, shaped by Buddhist concepts of health and moderation, as well as evolving global aesthetics. Educators interviewed in a Chulalongkorn University study (2024) observed that while BMI remains familiar to most Thais, younger generations express greater interest in holistic wellness, including understanding fat distribution and muscle mass. However, the risk of body shaming and unhealthy diet practices remains—a challenge for public health messaging. The Ministry of Education has urged schools to combine any new assessment tools with positive health promotion, rather than punitive reporting on body size, to avoid stigmatization.
Ultimately, there are several steps Thai readers, healthcare providers, and policymakers can take right now:
- For individuals: If you have access to a BIA machine at your hospital, clinic, or local fitness center, request a body composition analysis as part of your next checkup. Remember, healthy living is about more than weight—focus on reducing excess body fat through regular exercise and balanced, traditional diets rich in fruits, vegetables, and lean proteins.
- For clinicians: Consider incorporating BIA into patient assessments, especially for those with “normal” BMI but other risk factors for heart disease or diabetes. Discuss the new research with management to explore affordable approaches to implementing the new technology.
- For policymakers: Encourage pilot programs using BIA in public hospitals and community health centers. Support research on what healthy BF% means for Thais of various ages and backgrounds, building local data to inform future guidelines.
- For educators and media: Promote public awareness campaigns highlighting the importance of body composition, not just body weight, and guard against body image stigma.
As Thailand seeks to meet the challenges of non-communicable diseases amid rapid lifestyle changes, this new evidence points toward a future where understanding our true health goes beyond the number on the scale, encouraging all Thais to take a holistic approach to wellness.
For further reading, see the full report at Medscape and Thailand-specific obesity research on The Lancet Regional Health – Western Pacific and recent local publications via the Thai Journal of Obesity (TJO).