Context: The Lancet medical journal has proposed a new definition and method for diagnosing obesity, beyond simply looking at a person’s Body Mass Index (BMI).
Relevance of the Topic: Prelims: Basic idea of new definition for Obesity; Body Mass Index (BMI).
How is obesity measured at present?
- Globally, the standard method of determining obesity employs Body Mass Index (BMI) cut-offs, as the sole determinant.
- BMI is calculated by dividing a person’s body mass (weight) in kilograms by the square of their height measured in metres.
- Global BMI cut-offs: A person with-
- BMI of less than 18.5 is considered to be underweight.
- BMI between 18.5 and 24.9 is considered to be normal.
- BMI between 25 and 29.9 is considered to be overweight.
- BMI over 30 is considered to be obese.
Why has the BMI method been criticised?
- Relying solely on BMI cut-offs leads to both over-diagnosis and under-diagnosis of obesity.
- People with excess body fat may not always have a BMI of more than 30. But they may suffer the health consequences of obesity.
- People with high muscle mass may have a BMI of more than 30 while being extremely healthy.
- E.g., In India many seemingly lean people with a BMI of less than 30 have abdominal fat that can affect the functioning of various organs.
- Indians get diabetes, hypertension, heart diseases and other consequences of obesity, even at lower BMI. This is because they have higher body fat percentages and central obesity as compared to Western counterparts.
- In India, BMI cut-offs were revised. BMI between 23 to 24.9 is deemed overweight and BMI of more than 25 indicates obesity.
What is the new proposed definition of Obesity?
- Lancet Commission defines clinical obesity as a chronic illness that results in alteration in organ functions, regardless of other conditions a person might have.
- The new definition takes into account physical parameters such as height, weight, waist circumference, muscle mass, and functioning of various organs.
- Clinical obesity cannot be self-diagnosed. A physician will have to check for all kinds of signs and symptoms, such as:
- breathlessness, wheezing, sleep apnoea, high triglyceride levels, metabolic dysfunctions, non-alcoholic fatty liver disease.
- changes in reproductive system, heart failure, chronic fatigue, and knee and joint pain, physical activity of individuals etc.
- Pre-clinical obesity: The new definition does away with the overweight category, and adds a category called pre-clinical obesity- where a person has excess body fat, but no associated ongoing illness.
How is body size calculated for this evaluation?
- Lancet Commission suggests looking at any two of the following four parameters for evaluating body size:
- BMI
- Waist circumference
- Waist-to-hip ratio
- Waist-to height ratio
- Doctors may also use methods such as Dexa scan to directly measure body fat.
New definition for Indians:
- Indian guidelines will use the classifications of stage 1 and stage 2 obesity, instead of pre-clinical and clinical obesity.
- Stage 1 obesity: BMI of more than 23 — waist circumference and waist-to-height ratio is optional for this group — but do not have symptoms that show limitations in day to day activities.
- Stage 2 obesity: BMI of more than 23 and individual meets one more physical parameter of obesity (such as waist circumference and waist-to-height ratio), and suffer from obesity-associated limitations, co-morbid diseases.
Latest development in Obesity treatment:
- Drugs like Ozempic, Wegovy, Zepbound are developed to deal with clinical obesity. They belong to a class of drugs known as glucagon-like peptide-1 receptor agonists (GLP-1RAs), which mimic a hormone (GLP-1) in the body that helps control insulin and blood glucose levels and promotes feelings of satiety. However, they are not free from complications.