Context: 

Recently, the Lancet (a London-based commission of the medical journal) has proposed a new definition and method for diagnosing Obesity. 

More on the news:

• The new definition published by the Lancet Diabetes & Endocrinology Commission (a group of 58 leading experts from various medical specialities and countries) moves beyond a simple cutoff mark for Body Mass Index (BMI), used as the standard worldwide. 
• The guidelines were backed by organisations including the American Heart Association, the Chinese Diabetes Society, and the World Obesity Federation.

Why a New Definition for Obesity?

• BMI has been the standard for diagnosing obesity worldwide.

It is simple to calculate but has the following limitations.

• BMI has long been used for its simplicity, calculated by dividing weight (kg) by height (m²).
• It doesn't consider muscle mass, fat distribution, or ethnicity. This means that two people with the same BMI may have different health risks.
• It doesn’t differentiate between subcutaneous fat (under the skin) and visceral fat (around internal organs), with Visceral fat is more dangerous and linked to higher risks of heart disease, diabetes, and other serious conditions.

New Definition Proposed by the Lancet Commission: 

• The commission defines two categories:

Preclinical Obesity:

• Excess body fat without any ongoing illness or symptoms.
• May require monitoring and lifestyle changes (diet, exercise).
• It may represent an earlier stage of obesity or phenotype with a lower risk for organ function issues.

Clinical Obesity:

• A chronic illness where excess fat impacts normal organ function.
• Causes serious health complications like heart disease, diabetes, etc.

Obesity measurement Under the New Guidelines

Evaluation by a Doctor:

• Physical parameters (height, weight, waist circumference).
• Check for symptoms or conditions such as breathlessness, fatigue, joint pain, heart failure, chronic fatigue and metabolic issues.

Body Size calculation for the evaluation:

• The commission suggests using additional methods to check for excess body fat along with BMI:
• Doctors can measure waist circumference, waist-to-hip ratio, or waist-to-height ratio.
• They may use any two of these measurements together to assess body size, regardless of BMI.
• Advanced methods like DEXA scans and CT scans can also be used to directly measure body fat.

New Obesity Definition for Indians

The new Indian definition follows the Lancet guidelines but uses Stage 1 and Stage 2 Obesity classifications instead of Preclinical and Clinical Obesity.

• Stage 1 Obesity: BMI > 23, no major symptoms or health issues.
• Stage 2 Obesity: BMI > 23 with symptoms affecting daily life or chronic conditions like diabetes or hypertension.

BMI is still the entry point for diagnosis in India because of its familiarity and easier implementation.

Treatment Plans suggested:

Preclinical Obesity:

• Focus on preventing further weight gain to clinical obesity.
• Encourage lifestyle changes such as a balanced diet and regular exercise.

Clinical Obesity:

• Tailored treatment based on symptoms and health status.
• Use of medications (like GLP-1 receptor agonists) or surgery if necessary.
• Treatment should focus on improving health markers, not just weight loss.