Poor nutrition adversely affects exercise performance by leading to insufficient energy levels, decreased endurance, and slower recovery. A diet lacking essential nutrients can result in muscle fatigue, reduced strength, and a diminished ability to perform at optimal levels. Furthermore, inadequate hydration and nutrient intake may impair concentration and motivation during workouts. Over time, poor nutritional choices can hinder athletic improvements and increase the risk of injuries, ultimately affecting one’s overall fitness progress and well-being.