Final answer:
Both genetic factors and lifestyle choices, specifically diet and exercise, are significant determinants of adult body weight and obesity. Genetics can influence metabolism and appetite, while diet and exercise manage calorie balance. Environmental factors also affect access to healthy food choices and opportunities for physical activity.
Step-by-step explanation:
When assessing what contributes to body weight and obesity, it's important to consider both genetic and environmental factors. Genetic influences can predispose individuals to obesity by affecting appetite and metabolism, particularly in environments with plentiful food energy. Family studies indicate that obesity has a strong genetic component, with a higher likelihood of obesity when both parents are obese. On the other hand, diet and exercise play a crucial role in managing calorie intake and expenditure, which directly impacts body weight.
Factors such as socioeconomic status and physical environment can influence dietary habits and access to exercise opportunities, further complicating the obesity equation. Furthermore, where fat is deposited in the body is partly determined by hormones and genetics, with different patterns observed in males and females. In short, both genetics and lifestyle choices, including diet and exercise, are significant in determining adult body weight. However, significant deviations from a healthy diet and optimal physical activity levels are still primary causes of obesity.