Yes, it is true that exercise can reduce a person's appetite in some cases. Physical activity causes the body to produce hormones such as adrenaline and noradrenaline, which can temporarily suppress appetite. Additionally, exercise can help regulate hormones that control hunger, such as ghrelin and leptin. Studies have shown that moderate to intense exercise can reduce hunger and food cravings in some individuals, especially in the short term. However, the effect of exercise on appetite can vary based on factors such as the type and intensity of the exercise, individual physiology, and overall energy balance. It's important to note that regular exercise is still an essential part of maintaining a healthy lifestyle, even if it does not always lead to a significant reduction in appetite.