The meat of the obesity problem
The Lancet urges a shift from BMI to better obesity metrics, emphasizing the need for accurate assessments to address rising obesity rates, especially in India.
Obesity’s links with many non-communicable diseases (NCDs) and the consequent health burden make it a health concern of singular importance for both people and policy. Yet, for decades now, the world has used a rather flawed metric to diagnose it — Body Mass Index (BMI), an estimation of body fat content based on weight relative to height. While a BMI of 30 or above is considered obesity, this remains prone to errors of both over- and under-estimation of body fat content and attendant risks. To illustrate, while certain athletes will register a BMI upwards of 30, it usually is because of, among other things, higher muscle mass or bone weight. At the same time, not all people with excessive body fat clock a BMI number above the obesity threshold. BMI, therefore, has been an inaccurate measure, confounding responses to individual health all this while.

It is against this backdrop that the Lancet Diabetes and Endocrinology Commission has called for moving away from BMI-based obesity diagnosis. In its report, the commission highlights the need to develop consensus on use of more appropriate obesity metrics, such as waist circumference, waist-hip ratio, and waist-height ratio, factoring in gender-, age, and ethnicity-specific cut-offs. While there can be no surer estimation than direct measurement of body fat, where this is not possible, the commission recommends using one of these body size metrics along with BMI or two body size metrics, BMI notwithstanding. It also recommends that obesity be categorised as either pre-clinical obesity or clinical obesity — the latter being associated with changed/impaired organ function and inability to conduct daily activities — with the relatively more aggressive forms of treatment (including drugs and surgery) reserved for clinical obesity. The need now is for the medical community to adopt metrics that can help capture the true picture on obesity.
For India, where obesity has become a major health concern even as undernutrition challenges remain, population-level well-being translates into a problem of understanding individual nutrition challenges and addressing these. More so because the country, as data from a Lancet study last year shows, faces serious future risks from obesity, with large populations of obese children (ages 5-19) and women above 20 (maternal obesity has a strong correlation with later years obesity among children). There are portents from the consumption data as well — falling whole foods consumption in households even as processed food and sugary drinks intake is rising. Against such a backdrop, the government must push the adoption of holistic measures of obesity, even as various food support programmes evolve into nutrition support ones.
