What is a primary role of physical activity in managing energy balance?

Physical activity plays a crucial role in managing energy balance primarily by increasing energy expenditure. When individuals engage in physical activity, their bodies require more energy than when they are at rest, leading to an increase in the number of calories burned. This heightened energy expenditure can help create a calorie deficit, which is essential for weight loss, or can support weight maintenance by balancing the calories consumed with those burned.

Regular physical activity contributes to overall health and fitness, enhances metabolic health, and can have positive effects on body composition, such as reducing body fat and increasing lean muscle mass. Muscle tissue burns more calories at rest compared to fat tissue, leading to a more favorable energy balance over time.

In contrast to this primary function, the other options do not accurately reflect the key contributions of physical activity in energy management. While reducing total food intake can certainly impact energy balance, it is not the primary role of physical activity. Decreasing metabolic rate contradicts the effect of regular exercise, as physical activity typically boosts metabolism and maintains energy expenditure. Similarly, while maintaining current weight is a benefit of physical activity, it is not its sole purpose; a primary role is indeed to actively stimulate energy expenditure, facilitating both weight loss and maintenance strategies.