Obesity is a growing global challenge, affecting 1/8th of the world’s population. Obesity rates in India are rising at an alarming pace, affecting both urban and rural populations.
According to a Lancet study, obesity is now classified into 2 stages:
- Preclinical Obesity or the early stage
This stage is characterised by excess adiposity but no current organ dysfunction or functional limitation. It still carries a higher future risk of developing metabolic and cardiovascular diseases.
- Clinical Obesity or the disease state
This chronic disease state is directly caused by excess adiposity. It leads to organ dysfunction, metabolic disturbances, and reduced quality of life. Diagnosis should not be based solely on BMI; it should also include waist circumference, waist-to-hip ratio, and waist-to-height ratio.
Conventional Body Mass Index classifications fail to capture the unique fat distribution and metabolic risks among Asian Indians. The World Health Organisation defines overweight as a BMI of >25 kg/m2 and obesity as >30 kg/m2. However, research over the past two decades has shown that these cut-offs do not apply equally across all ethnicities.
South Asians and East Asians have a higher percentage of body fat at lower BMI levels than Caucasians. This means that they develop obesity-related diseases like type 2 Diabetes, hypertension, and cardiovascular disease at a lower BMI than the Western population.
WHO and regional health bodies have revised the BMI categories for the Asian population.
The revised Asian BMI of 23 kg/m2 is considered overweight, and a BMI of 25 kg/m2 qualifies as obesity.
This need for revision of the BMI scale is because Asians have a higher percentage of body fat than Caucasians at the same BMI. This excess fat is stored around the organs and increases the metabolic risks. This is called visceral fat.
A DEXA study shows that at the same BMI, Asians have 3-5% more body fat than Europeans.
South Asians are genetically predisposed to insulin resistance. Even at BMI levels considered normal by Western standards, many Asians show high fasting insulin and HOMA-IR scores. This is why people with low BMI develop type 2 diabetes early.
Waist circumference and waist-to-height ratio are better indicators of metabolic risk than BMI alone.
The new recommended cut-offs are
For men waist circumference is ≥ 90 cm or 34.5 inches, and for women, it is ≥ 80 cm or 31.5 inches.
WHtR > 0.5 predicts diabetes and CVD risk more than BMI.
So, these new revised BMI classifications will help doctors identify high-risk individuals earlier, leading to a proactive lifestyle and medical interventions. More people will qualify for preventive programs for diabetes and heart disease.
Countries like India, China, Japan and Southeast Asia are updating obesity prevention guidelines. Weight-loss medications and bariatric surgery eligibility will be adjusted based on new BMI cut-offs.
But with this new classification of BMI, does it make everybody fall under the obese category? This is where Body Composition Analysis comes into the picture. It gives a detailed report of the composition of the patient’s body, and the intervention and management of obesity can be planned effectively. BMI alone doesn’t give the full picture; it is just a tool to predict the risk, and it may not always be correct. A person with higher muscle mass will fall under the obese category, which is inaccurate.
Going forward, healthcare professionals must integrate BMI with waist circumference, waist-to-height ratio, body composition analysis and metabolic markers to provide the best patient care.
Kripa, is a Specialist Dietitian at The London Obesity & Endocrine Clinic. She has helped many patients overcome weight management barriers. ©Simplyweight
