Obesity
Obesity is a chronic condition in which excess body fat accumulates to a degree that can damage health. Clinically it is defined by a body mass index (BMI) of 30 or above, though waist circumference and body-fat distribution matter too. Rates of obesity and related metabolic disease are rising sharply in urban centres worldwide, where sedentary work and energy-dense diets have shifted population health trends.
Key points
- Hormones that govern hunger and fullness, such as leptin and ghrelin, tend to shift after weight loss in ways that push appetite back up.
- Clinically defined by a body mass index of 30 or above, obesity also depends on where and how body fat is distributed.
- Alongside lifestyle changes, medicines may help: orlistat limits fat absorption, while combining bupropion with naltrexone targets appetite and reward pathways.
Why it is hard to treat by willpower alone
Obesity involves hormonal and neurological feedback loops that actively resist weight loss. Leptin and ghrelin, the hormones governing hunger and satiety, adjust in ways that increase appetite after weight is lost, which is why sustained change is difficult without structured support. Lifestyle work (calorie awareness, movement, sleep) forms the foundation, but for many people medicines play a meaningful role. Weight management options may include orlistat, which reduces dietary fat absorption, or combination approaches targeting appetite and reward pathways such as bupropion and naltrexone together.
When to seek medical attention
Unexplained chest pain, breathlessness at rest, or signs of blood-sugar problems such as extreme thirst and blurred vision alongside significant weight gain warrant prompt medical review. A clinician can also assess for underlying causes such as hypothyroidism or medication side effects before treatment begins.