Sedentary behavior negatively affects metabolism by slowing down caloric burn and promoting weight gain. Prolonged sitting and inactivity can decrease muscle mass, making the body less efficient at using energy. This can further lead to insulin resistance and increased risk of chronic conditions such as obesity, type 2 diabetes, and cardiovascular disease. Moreover, sedentary lifestyles can contribute to fatigue and decreased energy levels, which can make it difficult for individuals to engage in physical activity, thus perpetuating a cycle of inactivity and metabolic decline.