Understand Obesity
Understanding the biology behind obesity — and why it is a complex, chronic medical condition, not a failure of willpower — is the foundation for making sense of why treatments work the way they do.
Quick read · 2 min
What is obesity?
Global prevalence, how BMI is used and its limitations, and what it means to be clinically obese.
Health consequences
How obesity increases risk of type 2 diabetes, heart disease, cancer, sleep apnoea, and other conditions.
Why weight loss is hard to sustain
The biology of hunger hormones, leptin resistance, and why the body actively defends its set point weight.
- •Obesity is a chronic medical condition — not a willpower problem
- •Over 1 billion adults worldwide are classified as obese
- •The body actively defends its weight using hormones — this is why dieting alone rarely works long-term
- •Effective treatments work by addressing the biology directly
Based on clinical trials · No rankings · Every claim linked to source
Last reviewed: March 2026
Why this matters for treatment
Obesity is now understood as a chronic disease driven by hormonal, genetic, and environmental factors. The treatments reviewed on this site — GLP-1 drugs, dual agonists, surgery — work because they directly address these biological mechanisms, not just calorie balance.