Genetics influence both fitness and body composition by determining factors such as metabolism, muscle fiber type, and fat distribution. Some individuals may have a genetic predisposition to excel in endurance or strength activities, affecting their training outcomes. Genetic factors also play a role in how the body responds to diet and exercise, influencing weight loss or gain efforts. While genetics set certain parameters, lifestyle choices such as diet and physical activity can significantly modify these effects. Understanding genetic influences can help tailor fitness approaches for individuals.