For years, Body Mass Index (BMI) has been the standard tool for assessing whether an individual has a healthy weight. But doctors are now referring to it as an outdated and an often-misleading metric.

BMI is a rough guide doctors use to check if a person’s weight is in a healthy range for their height. It doesn’t directly measure body fat – it just uses your weight and height to put you into a category like underweight, normal, overweight, or obese.

Dr. Anshita Aggarwal, assistant professor of endocrinology at Ram Manohar Lal Hospital and Medical College, New Delhi thinks BMI offers only a partial picture of a person’s health. 

“BMI is overtly overrated in today’s medical landscape,” Dr. Aggarwal told First Check. “It looks at how much you weigh relative to your height, but not every 5-foot person with the same weight is obese versus healthy. BMI fails to distinguish between muscle and fat, does not account for fat distribution, and ignores critical factors like metabolic health.”

Dr. Anjana Bhan, an endocrinologist with over 30 years of experience at Max Healthcare, New Delhi, said the flaws are especially pronounced in India and among South Asians worldwide. 

“South Asians are prone to what we call ‘lean fat’ — they may have a normal BMI but carry excess visceral fat, particularly around the abdomen, which increases their risk for diabetes and heart disease,” Dr. Anjana Bhan told First Check. “This phenomenon, sometimes dubbed the “Y-Y paradox,” refers to individuals who appear thin by BMI standards but have high body fat percentages and metabolic risk — a pattern common among Indians.”

According to Dr Aggarwal people of Asian descent can face increased health risks at lower BMI thresholds than the general population. “I’ve seen that BMI can be normal while the person has a high fat percentage, and is obese. People with this condition, known as normal weight obesity, may have the same serious health risks as someone who is obese,” she explained.

Alternative metrics to BMI

Both the doctors said that they now recommend a range of alternative assessments to better capture an individual’s health risks. To detect harmful abdominal fat – which is more closely linked to metabolic disorders than overall body weight – doctors now recommend measuring waist circumference and waist-to-hip ratio. While new genetic testing emphasizes the heritability of obesity and individual variations in fat storage, blood tests for glucose, cholesterol, and liver function offer information about metabolic health.

“Obesity is a spectrum,” said Dr Aggarwal, “The current broad definition of obesity fails to address the diverse health implications of the condition.”

As India faces rising rates of diabetes and heart disease, and with the new type 5 diabetes especially being a cause for concern to India, the doctors say that clinicians should move beyond BMI and adopt a more comprehensive, individualized approach to health. “It’s not just how much fat you have, it’s also where the fat is, that’s important,” Dr Bhan said.

With new research and technologies, the hope is that more at-risk Indians — including those with “lean fat” profiles — will be identified early and receive the care they need.

Also read: Explainer: What BMI can and cannot tell you about your health – First Check