Final answer:
Obesity is caused by complex interactions between genetic and environmental factors, including excessive food intake, inadequate physical activity, and genetic susceptibility.
Step-by-step explanation:
The etiology of obesity is the result of complex interactions between genetic and environmental factors. It is most commonly caused by a combination of excessive food intake, inadequate physical activity, and genetic susceptibility. Various genes that control appetite and metabolism, as well as environmental factors such as socioeconomic status and physical environment, contribute to the development of obesity.