Obesity is caused by a complex interplay of multiple factors, with the fundamental cause being an energy imbalance where more calories are consumed than the body uses. This can be influenced by genetics, lifestyle choices, metabolic and hormonal factors, medical conditions, medications, environmental and socioeconomic factors, and certain life stages.
Key Causes of Obesity
- Caloric imbalance: Consuming more calories than are burned through normal activities and exercise is the most common cause of obesity.
- Genetics: Genetics influence how body fat is stored, appetite regulation, energy metabolism, and susceptibility to weight gain. Specific gene variants can increase obesity risk substantially. Obesity tends to run in families due to both genetic and shared lifestyle factors.
- Lifestyle factors: Poor diet high in calories, processed foods, sugary drinks, and inactivity including sedentary behaviors like screen time contribute heavily to obesity.
- Medical conditions and medications: Certain conditions like hypothyroidism, Cushing syndrome, and Prader-Willi syndrome can cause obesity. Some medications such as steroids, antidepressants, diabetes medicines, and antipsychotics also contribute.
- Environmental and socioeconomic factors: Availability of cheap, calorie-dense processed foods, social and economic influences, and lifestyle environment impact obesity risk.
- Other factors: Insufficient sleep, stress, hormonal changes, psychological factors, and intrauterine environment during pregnancy can play roles in obesity development.
Obesity is increasingly understood as a disorder of energy homeostasis involving sustained positive energy balance and an altered body weight set point rather than purely excess calorie intake.
In summary, obesity results from complex genetic and environmental interactions where excessive calorie intake, poor diet, inactivity, and various biological and social factors converge to promote excess body fat accumulation.
