BMI has been the benchmark in evaluating health and fitness for many years. The formula is quite simple: weight in kilograms divided by the square of height in meters. This would easily tell if one is underweight, within the healthy weight range, overweight, or obese. But with new research findings, scientists are now questioning its accuracy and usefulness as a total measure of body composition.

The report, published in The Lancet Diabetes & Endocrinology, has sparked a global conversation on rethinking BMI. Supported by more than 50 international medical experts, the report suggests classifying obesity into "clinical" and "pre-clinical" types for better diagnosis and treatment. The shift underscores a growing consensus: BMI alone may not tell the full story of your health.

While BMI is simple to calculate and universally accessible, it is far from perfect. It does not consider muscle mass, bone density, or fat distribution, leading to misleading conclusions in some cases. For example, athletes with a high muscle mass may be considered overweight, whereas individuals with normal BMI might carry unhealthy amounts of visceral fat.

A landmark study in JAMA Network Open studied more than 155,000 postmenopausal women and found that women with a normal BMI but a waist size over 35 inches were more likely to die from heart disease or cancer compared with their counterparts whose waists are smaller. That makes a great case for how BMI can be insufficient and fat distribution must be factored into account.

Not all body fat is equal. Subcutaneous fat, which lies just beneath the skin, is relatively harmless. The real health danger lies in visceral fat—fat that surrounds internal organs. Unlike subcutaneous fat, visceral fat is metabolically active, releasing stress hormones like cortisol and inflammatory substances that raise blood pressure, blood sugar, and cholesterol levels. These effects significantly increase the risk of conditions such as heart disease, type 2 diabetes, and certain cancers.

BMI Isn't Always the Best Measure of Body Composition — Here's What to Use Instead

Since BMI is not the most reliable measure, scientists and doctors have sought other means to measure body composition more accurately.

1. Waist Circumference

A simple tape measure can provide valuable insight into your health. Measure your waist at the level of your belly button, ensuring the tape is parallel to the ground. For women, a waist measurement under 35 inches is considered healthy, while for men, the goal is under 40 inches.

2. Waist-to-Hip Ratio

This is the ratio of your waist circumference to that of your hips. To calculate it, divide your waist measurement by your hip measurement. According to the National Center for Biotechnology Information, a ratio under 0.8 for women and 0.9 for men is considered healthy.

3. Body Roundness Index (BRI)

A newer method that seems to be receiving more attention involves the Body Roundness Index or BRI: height, weight, and girth are placed together to represent a more advanced view of what body composition says. Research presented in JAMA Network Open offers evidence that this BRI predicts mortality risk greater than BMI in some cases- a promising weapon for public health.

Also Read: Using BMI To Classify People As Obese Is Flawed Say Experts

Ways To Cut Off Unhealthy Fat

The good news is that visceral fat responds well to lifestyle changes. Here are three evidence-based strategies:

Time-Restricted Eating

Adopting an eating window of 12 hours—such as from 7 a.m. to 7 p.m.—can significantly reduce visceral fat, according to a study published in Nutrition Research Reviews. This approach not only helps control caloric intake but also reduces late-night snacking, a known risk factor for abdominal obesity.

Limit Alcohol Intake

Excessive alcohol consumption is associated with increased belly fat. A 2017 study published in Public Health Nutrition revealed that alcohol increases the levels of insulin and encourages the storage of fat in the abdominal area. Limiting alcohol to occasional indulgence helps avoid weight gain in this region.

High-Intensity Interval Training (HIIT)

HIIT involves repeated episodes of high-intensity exercise separated by periods of rest. A review in *Sports Medicine* concluded that HIIT is very effective in reducing visceral and total body fat. It can be noted that adding just 20 minutes of HIIT two times a week can make all the difference.

The reliance on BMI as a sole indicator of health is increasingly being challenged. While it remains a convenient screening tool, its limitations necessitate a broader approach that considers factors like fat distribution, waist circumference, and new metrics such as BRI.

In the simplest of words, health is multi-dimensional, and shifting perspectives from considering weight solely to broader measures of body composition will get people a much clearer understanding of where their health risks are so that they can take the action required for a better quality of life. Through adjustment to diet, exercise, or perhaps through innovative metrics like BRI, health is well within reach of the individual.

This dynamic conversation raises the point about personalized health screenings, which helps everyone get more relevant tools fitting their unique lives and circumstances. As body composition research is enhanced, so do the futures look brighter and brighter for the times of measurement when it comes to health.

Definition and diagnostic criteria of clinical obesity. The Lancet Diabetes & Endocrinology.

Association of Normal-Weight Central Obesity With All-Cause and Cause-Specific Mortality Among Postmenopausal Women. JAMA Netw Open. 2019

Waist-Hip Ratio. NIH.

Physiological responses to food intake throughout the day. Nutr Res Rev. 2014

Association between abdominal obesity and alcohol drinking pattern in normal-weight, middle-aged adults. Public Health Nutr. 2017

For years, body mass index (BMI) has been a key health marker to track obesity. But a recent study suggests that not everyone classified as obese based on their BMI may have obesity-related health problems. Researchers say just considering BMI alone may lead to incorrect diagnosis in some people while overlooking others with excess body fat and related health risks.

The international study, involving more than 844,000 adults across China, the UK, the US and Spain, supports a different approach that considers body fat distribution, waist measurement and the impact of excess fat on organ function.

Researchers propose distinguishing between two categories: pre-clinical obesity, in which excess body fat increases health risks but has not impaired organ function, and clinical obesity, in which excess fat is already affecting the body's ability to function.

BMI Alone Not Enough To Diagnose Obesity

Also read: Why WHO Wants To Use Smartwatches To Track Physical Activity & Sedentary Behaviour At A Population Level?

BMI is calculated by dividing a person's weight in kilograms by their height in metres squared. It is used to classify people as underweight, normal weight, overweight or obese.

However, BMI does not directly measure body fat or show where fat is distributed. It also cannot distinguish between fat and muscle mass. Consequently, two people with the same BMI may have very different body compositions and health risks.

The researchers found that adding waist circumference and waist-to-height ratio to BMI helped identify people whose excess body fat might otherwise be missed.

The analysis suggested that BMI alone missed obesity level body fat in up to 8.6% of participants, while incorrectly classifying up to 3.1% as having obesity in the study groups.

Professor Francesco Rubino, senior author of the study and Chair of Metabolic and Bariatric Surgery at King's College London, said, “Body mass index alone cannot tell us whether someone is already ill or at risk of illness, or what care they need, leaving people vulnerable to both undertreatment and overtreatment.”

Difference Between Clinical And Pre-Clinical Obesity

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The researchers used a framework proposed by the Lancet Diabetes and Endocrinology Commission in 2025. It separates obesity into two categories based on whether excess body fat has affected a person's health.

• Pre-clinical obesity: A person has excess body fat that increases their risk of developing health problems, but their organ function and everyday activities remain unaffected.

• Clinical obesity: Excess body fat has impaired organ function or affected a person's ability to perform daily activities. It is considered an active disease that requires clinical assessment.

The study estimated that only around 23% to 31% of people classified as having obesity across the four study populations had clinical obesity. This represented approximately 5.6% to 10.9% of the overall adult populations studied.

When Do People With Pre-Clinical Obesity Develop Health Problems?

The researchers followed participants over time to examine how often pre-clinical obesity progressed to clinical obesity.

They found that approximately 77% to 91% of people classified as having pre-clinical obesity did not progress to clinical obesity over 10 years. However, progression rates differed across the study populations.

Clinical obesity was linked with a higher risk of death while pre-clinical obesity had a more modest increase in risk.

Professor Rubino said, “Preclinical obesity should therefore be neither treated automatically as active disease nor dismissed as harmless. Some people may need preventive treatment, but its intensity should match their individual risk.”

The findings do not mean that people with pre-clinical obesity should ignore excess body fat. Rather, they highlight the importance of assessing individual health risks instead of making treatment decisions based on BMI alone.

People with excess body fat may still benefit from lifestyle hanges, treatment and preventive care even if they have not developed organ dysfunction.

Smartwatches and fitness trackers are widely used for counting daily steps and tracking workouts by millions. But the World Health Organization (WHO) is now seeking to task these wearables with bigger responsibilities. The global health body has issued proposals for wearable devices that could help countries measure physical activity and sedentary behaviour across populations.

In a notice published on November 8, WHO invited researchers, health authorities, technology developers and other stakeholders to review a draft Target Product Profile (TPP) for wearable devices worn on wrists. The aim is to ascertain what these devices should be capable of measuring before they are incorporated into national and subnational public health monitoring systems.

The proposal will remain open until December 6, 2026. WHO will use the feedback to revise and finalise the document and inform future implementation guidance.

WHO Want To Use Smartwatches For Public Health Monitoring

Also read: Lancet Study Says Obesity Drug Mazdutide Shows 18% Weight Loss In 32 Weeks: How Does It Compare To Wegovy?

Physical inactivity is a major risk factor for non-communicable diseases, including cardiovascular disease, type 2 diabetes and certain cancers. Sedentary behaviour, which involves spending prolonged periods sitting is also the cause of various adverse health outcomes.

Countries currently rely heavily on surveys to understand how physically active people are. However, these often depend on people reporting their own activity, which can lead to inaccurate data.

Wearable devices could provide a more objective way to collect information over a certain period of time. Instead of relying entirely on questionnaires, health authorities could use data from these devices to understand how much people move, how long they remain sedentary and how activity patterns vary across different population groups.

WHO says wearable technology could complement existing surveillance methods as countries work towards improving global physical activity targets.

WHO's Proposed Standards

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The draft TPP outlines minimum specifications for smartwatches intended for population-level monitoring. It considers what makes a device suitable for collecting data across different populations.

The proposed framework covers:

• Measurement capabilities: What physical activity and sedentary behaviour indicators a device should be able to capture.
• Technical specifications: The minimum and additional features required for devices to be suitable for public health surveillance.
• Data access: How information can be retrieved, processed and used by health monitoring systems.
• Implementation: Practical considerations involved in deploying devices across communities and integrating them into existing surveillance programmes.
• Scalability and sustainability: Whether the technology can be used consistently across countries with different resources and technical capacities.

WHO is interested in feedback on whether the specifications proposed are practical and relevant to countries with limited resources.

Why Can't Countries Use Existing Smartwatches?

Although such wearables are widely available, their measurements are not interchangeable. Different manufacturers use different sensors, algorithms and methods to calculate steps, activity levels and sedentary time. As a result, two devices worn by the same person may produce different estimates.

A systematic review published in npj Digital Medicine in January 2026 examined 82 studies evaluating Apple Watch measurements across 14 health metrics. It found that measurement accuracy varied depending on the metric and testing conditions. While heart-rate measurements showed good overall agreement, step counts had moderate accuracy and energy expenditure data was inconsistent too.

This illustrates the need for standardisation. If countries use different devices and measurement methods, comparing physical activity data across populations becomes needlessly challenging.

WHO's proposed framework is intended to address these differences by identifying the device characteristics and protocols needed for consistent data collection.

Cost, access, privacy and digital literacy remain important challenges when it comes to implementing WHO's proposal. People without smartphones, reliable internet access or the ability to buy wearable devices could be underrepresented.

There are also questions about how personal movement data would be stored, shared and protected. Governments would need clear safeguards to ensure that participation is voluntary, data is handled responsibly and findings represent the wider population.

Mazdutide, an experimental weight-loss drug, could soon join the ever-expanding market of GLP-1 medications. The results from a recent clinical trial funded by Eli Lilly has found that mazdutide has shown an average reduction of 18.1% in body weight over 32 weeks. The trial was published in The Lancet Diabetes & Endocrinology.

The findings have drawn attention because the experimental drug produced significant weight loss in less than eight months, establishing its position among existing medicines like Wegovy.

However, the findings come from a phase 2 trial involving 179 participants. Its comparison with existing players like Wegovy are yet to be done formally.

What Did The Mazdutide Study Find?

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Published in November 2026, the randomised, double-blind, placebo-controlled trial evaluated mazdutide in 179 overweight or obese adults with overweight but without type 2 diabetes.

Participants, who were recruited from 24 centres in the United States, received the once-weekly injections of different doses of the drug or a placebo. At 32 weeks, the average weight changes were:

• Mazdutide 16 mg: 18.1% reduction in body weight
• Mazdutide 10 mg: 15.6% reduction
• Mazdutide 3–6 mg: 7.3% reduction
• Placebo: 0.9% reduction

The study also reported further weight reductions by week 48, suggesting that weight loss had not reached its maximum by the primary assessment.

However, tolerability of the drug drew attention too. Gastrointestinal problems, including nausea, vomiting and diarrhoea, were among the most common side effects.

Around 20% of participants receiving the highest 16 mg dose quit the treatment because of adverse events, primarily gastrointestinal disorders.

How Does Mazdutide Work?

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Mazdutide works differently from semaglutide, the active ingredient in Ozempic and Wegovy. It activates two hormone receptors involved in regulating appetite and metabolism: glucagon-like peptide-1 (GLP-1) and glucagon.

GLP-1 helps regulate blood sugar, which slows down emptying of the stomach and increases feelings of fullness, which can reduce food intake.

Glucagon is another hormone involved in regulating blood glucose and energy metabolism. By activating glucagon receptors along with GLP-1 receptors, mazdutide can affect energy expenditure and metabolism in addition to regulating appetite.

This dual action distinguishes it from semaglutide, which primarily targets the GLP-1 receptor.

Mazdutide Vs Wegovy

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Ozempic and Wegovy contain the same active ingredient, semaglutide, but have different approved uses and dosing.

Ozempic is primarily prescribed for type 2 diabetes and certain cardiovascular and kidney conditions, while Wegovy is approved for weight management.Here is how the trial results compare:

Mazdutide 16 mg showed 18.1% weight reduction in 32 weeks. Wegovy 2.4 mg showed 14.9% in 68 weeks.

In the STEP 1 trial, published in The New England Journal of Medicine in 2021, participants with overweight or obesity who received semaglutide 2.4 mg lost an average of 14.9% of their body weight over 68 weeks. Participants did not have diabetes.

Although mazdutide's 18.1% result seems higher than the 14.9% reported with Wegovy, the comparison has limitations. The trials differed in duration, participant characteristics, doses and study design. A direct head-to-head trial would be needed to establish which treatment produces greater weight loss.

Is Mazdutide A Promising Weight-Loss Drug?

Mazdutide has also been studied in China. In the phase 3 GLORY-2 trial, participants receiving 9 mg lost an average of 16.65% of their body weight over 60 weeks, compared to 1.50% in the placebo group.

Its recent findings are promising but it is too early to call mazdutide more effective than existing treatments. The US study was a relatively small phase 2 trial, and its highest dose led to a high rate of discontinuation due to adverse events. Larger phase 3 trials are important to establish its long-term effectiveness, safety and tolerability.