What the commission changed
For decades, a BMI of 30 or more has been the working definition of obesity. In January 2025, a commission of 58 experts published in The Lancet Diabetes and Endocrinology argued that this is not enough to diagnose an individual, and 76 organizations endorsed its recommendations.
The commission did not throw BMI away. It kept BMI for what it does well, which is screening and tracking risk across large populations, and said it should not be used on its own as a measure of one person’s health. In its place, it proposed a two-step diagnosis: first confirm that a person carries excess body fat, then decide whether that fat is already causing illness.
Step one: confirming excess body fat
BMI is weight divided by height squared, so it cannot tell muscle from fat. The CDC’s BMI calculator itself sorts adults into weight categories, not body fat levels. Under the commission’s framework, excess fat is confirmed in one of these ways:
| Method | What it involves |
|---|---|
| Direct body fat measurement | A DEXA scan or bioimpedance body composition test |
| BMI plus one body measurement | Waist circumference, waist-to-hip ratio or waist-to-height ratio |
| Two body measurements | Any two of the above, regardless of BMI |
| Very high BMI | Above 40, where excess fat can reasonably be assumed |
The waist measures matter because fat stored around the organs drives much of the risk. Our page on how to measure visceral fat explains the options, from a tape measure to a scan.
Step two: clinical versus preclinical obesity
Once excess fat is confirmed, the commission splits people into two groups.
Clinical obesity is a chronic illness in its own right: excess fat is already changing how organs work or limiting everyday activities. The commission lists 18 criteria for adults, including:
- obstructive sleep apnea or breathlessness;
- heart failure, atrial fibrillation or raised blood pressure;
- the combination of high blood sugar, high triglycerides and low HDL cholesterol;
- fatty liver disease with scarring, or kidney changes with reduced filtration;
- male hypogonadism, meaning low testosterone linked to excess fat;
- chronic, severe knee or hip pain, or limits on daily activities such as bathing and dressing.
Preclinical obesity means excess fat with organs still working normally. The risk of future disease is higher, but there is no illness yet. It is not a clean bill of health, and the commission is clear that it calls for monitoring rather than reassurance.
Checking those criteria is mostly familiar medicine. Blood pressure readings and a history of breathlessness or snoring come first. Labs cover blood sugar and HbA1c, triglycerides and HDL, liver enzymes, and kidney markers such as eGFR, with testosterone added for men who have symptoms. A sleep study, a liver scan or a heart workup follows only when the history points that way.
The inclusion of hypogonadism on the list is worth noticing. It formally recognizes what many men experience: carrying excess fat can suppress testosterone, and losing it can help. Our page on obesity and low testosterone explains how the two feed each other.
Why muscular men with a high BMI get misclassified
The commission notes that BMI can overestimate body fat in people with more muscle or bone, such as athletes. Consider a man who is 6 feet tall, weighs 230 pounds and lifts four days a week. His BMI is about 31, which a chart labels obesity. If his waist is trim and a scan shows lean mass making up most of that weight, the new framework would not call it obesity at all.
The reverse also happens. A man with a “normal” BMI but a large waist can carry harmful fat that BMI misses. For Asian American men, the NIDDK treats a BMI of 23 or higher as overweight for diabetes risk, a lower cutoff than for other groups, and it flags a waist above 40 inches as a risk factor in men. Our answer on diabetes risk for Asian American men at lower BMI covers why.
Our page on whether BMI is accurate for muscular men goes deeper on where the number goes wrong, and the comparison of body composition analysis and BMI shows what each tool can and cannot tell you.
What the new framework means for treatment decisions
The split changes the conversation more than the toolkit. It also cuts both ways for men: some who were told they had obesity based on a chart will learn they do not, and some with a normal-looking BMI will learn that their waist and labs tell a different story. For clinical obesity, the commission frames treatment as treating an illness, aimed at improving the organ problems or limitations that defined it. For preclinical obesity, the focus shifts to lowering risk: monitoring, lifestyle changes and, for some people, medicine.
Day-to-day rules have not caught up yet. US drug labels and most insurance criteria still rely on BMI categories, so a man’s eligibility for a medicine is still judged partly on that number. What the framework adds is a better reason to measure properly before deciding anything, and a clearer way to explain why two men with the same BMI may need very different plans.
For men who are well above the usual thresholds, our page for men with a BMI over 35 covers the extra evaluation steps that apply.
How Ultimate Male measures more than BMI
At our San Gabriel and Downey clinics, a medical weight loss evaluation includes a body composition analysis alongside weight and waist measurements, plus labs that look for the organ effects the commission describes: blood sugar, cholesterol, liver and kidney function, and, for men with symptoms, testosterone. That combination shows whether excess fat is really the issue and whether it is already affecting your health.
If the numbers say your high BMI is mostly muscle, we will tell you so, and you will leave with a baseline worth repeating in a year. If they show clinical effects, you will get a plan aimed at those specific problems. Either way, the free 10-minute call is the place to start.
