Understanding Obesity

Obesity is a condition in which excess body fat can lead to health problems, such as diabetes, heart disease, joint pain, osteoporosis, and generalized stress. 

Measuring Obesity: A Simple Guide

Obesity is commonly measured using Body Mass Index (BMI), which is a simple calculation using a person’s weight and height. 

BMI = kg/m2

BMI categories:

• Underweight: BMI < 18.5

• Normal weight: BMI 18.5 - 24.9

• Overweight: BMI 25 - 29.9

• Obese: BMI ≥ 30

For children, BMI-for-age percentiles are used because their body composition changes with age. 

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A child is considered:

• Overweight if their BMI is above the 85th percentile.

• Obese if their BMI is above the 95th percentile for their age and sex.

Other methods, like waist circumference, body fat percentage, and waist-to-hip ratio, can provide additional insights, especially for individuals with a high muscle mass.

Understanding Obesity: Genetics vs. Lifestyle

 People often think that obesity is caused by eating too much and not exercising enough; however, science shows that heredity (genes) also plays a major role. Let us break this down into two main causes: genetic and lifestyle/environmental factors.

Some people inherit genes from their parents, making them more likely to gain weight. The main types are as follows:

A. Single-Gene Mutations (Monogenic Obesity)
This occurs when a single gene undergoes spontaneous changes, leading to severe obesity at a young age. Some examples include:

• LEP (Leptin) Deficiency – Leptin is a hormone that helps control hunger. Without it, people feel hungry all the time and eat too much food.
• LEPR
• MC4R (Melanocortin 4 Receptor) Mutation – This gene controls how full you feel after eating. Mutations in this gene can lead to overeating.

B. Syndromic Obesity
Some genetic disorders cause obesity along with other health problems, such as

• Prader-Willi Syndrome causes constant hunger, learning difficulties, and hormonal issues.
• Bardet-Biedl Syndrome leads to obesity, vision problems, and kidney diseases.

C. Polygenic Obesity
Instead of a single gene, multiple genes contribute to obesity by affecting the metabolism and appetite. For example:

• FTO increases the risk of obesity worldwide.

Even if a person has an obesity-related genetic disposition, lifestyle choices and environmental conditions can make a significant difference.

A. Poor Diet and Lack of Exercise

• Eating too many high-calorie, low-nutrition fast food, sugary drinks, and snacks.
• Insufficient physical activity and sedentary habits.

B. Hormonal and Metabolic Imbalances

• Hypothyroidism: Slow metabolism can facilitate weight gain.
• Cushing’s Syndrome – High levels of cortisol (a stress hormone) promotes fat buildup.

C. Stress and Emotional Eating

• Eating as a way to cope with sadness, stress, or boredom.

Binge-eating disorder – Frequent uncontrollable eating