What does it mean to be obese? More than a number on the scales, obesity involves excess body fat and its potential effects on health. For Asian adults, understanding BMI, waist size and individual risk is particularly important.
The word “obese” can be shocking. Perhaps it appears on a health screening report, beside a number you barely understand. You feel fine. Your clothes still fit. So what, exactly, is that label telling you?
Obesity involves excess body fat, but understanding its significance requires more than looking at someone or weighing them. Where fat accumulates, how the body functions and whether health problems have developed all matter.
That distinction is prompting experts to rethink how obesity is diagnosed, with particular relevance for Asian adults whose health risks can emerge at lower body weights.
What Does Obesity Actually Mean?
Obesity is a condition involving excess body fat that can threaten health. The World Health Organization (WHO) classifies it as a chronic, relapsing disease, meaning it can persist over time and return after improvement.
However, a body-size category does not describe everything happening inside an individual. Two people with the same weight and height may have different amounts of muscle, different fat distribution and different medical needs.
This is why “Do I have obesity?” and “Is excess body fat affecting my health?” are related questions, but require different information to answer.
What Can Your BMI Tell You?
Body mass index, or BMI, compares weight with height. To calculate it, divide your weight in kilograms by your height in metres squared.
For example, someone weighing 80kg at 1.65m tall has a BMI of approximately 29.4.
Under the WHO’s standard adult categories, a BMI from 25 to below 30 falls within the overweight range; 30 or above falls within the obesity range. These adult thresholds do not apply directly to children.
BMI is useful for flagging possible concerns, but it cannot distinguish muscle from fat. A muscular person may have a high BMI without excess body fat, while someone with less muscle may carry more fat than their BMI suggests.
Think of BMI as an opening question in a health assessment. It cannot supply every answer.
Why Do Asian Adults Have Different Risk Thresholds?
Many Asian populations develop weight-related health risks at lower BMIs. Consequently, waiting until BMI reaches 30 can overlook people who would benefit from assessment.
Singapore’s HealthHub identifies a BMI of 23–27.4 as indicating moderate cardiovascular risk, and 27.5 or above as indicating high risk for Asian adults. Some clinical guidance also uses 27.5 as the obesity threshold. These categories explain why different calculators or clinics may give different labels.
Waist size adds another clue. Fat stored deep within the abdomen, around internal organs, is particularly relevant to metabolic health. HealthHub flags waist measurements above 90cm for Asian men and 80cm for Asian women as suggesting abdominal obesity.
A person can therefore have abdominal obesity despite a BMI within the usual normal range. These measurements help identify risk; they do not establish whether organ damage has occurred.
Rethinking the Obesity Diagnosis
In January 2025, a commission published in The Lancet Diabetes & Endocrinology proposed looking beyond BMI to establish whether someone has excess body fat, then assessing its effect on their health.
It proposed two categories.
Clinical obesity means excess body fat is already reducing organ function or significantly limiting everyday activities. Examples include obesity-related breathing impairment or substantial difficulty performing tasks such as dressing.
Preclinical obesity means excess body fat is present, but organ function is preserved. The person has an increased risk of future illness, although that risk varies between individuals.
This is a proposed framework, rather than a universal replacement for existing definitions. “Preclinical” also does not mean someone should wait until they become unwell before seeking support.
The research behind the supplied reference illustrates why wording matters. A 2025 analysis of 142,250 adults across 56 countries found fewer people met an adapted clinical-obesity definition than a BMI-only definition. However, the researchers had limited health measurements and could not apply the full assessment.
A change in classification does not mean that people suddenly lost body fat or that their health risks disappeared.
At the end of the day, energy intake and expenditure matter, but they do not explain everyone’s circumstances. Genetics, appetite regulation, medicines, access to affordable food and the surrounding environment can all contribute.
Reducing obesity to willpower overlooks the biological and social factors that influence weight. A useful consultation explores those factors without assuming that someone’s body size reveals their habits or effort.
What Should You Do if You Are Concerned?
Arrange a review with a GP or family doctor if your BMI or waist measurement suggests increased risk. Ask what the measurements mean alongside your medical history, blood pressure, blood sugar and cholesterol results.
Mention changes in breathing, mobility or everyday functioning. These symptoms need assessment rather than being automatically attributed to weight.
Support may involve nutrition advice, physical activity adapted to your abilities, behavioural support, medicines or surgery, depending on your circumstances. Treatment decisions should weigh likely benefits against risks, with goals that include better health and function.
