Act as a certified sports nutritionist with 10+ years of experience working with elite athletes. Provide a detailed explanation of how carbohydrates impact [TYPE OF ATHLETE, e.g., marathon runners, weightlifters, or soccer players] during [SPECIFIC PHASE OF TRAINING, e.g., endurance events, strength training, or recovery]. Include [NUMBER, e.g., 3-5] scientifically-backed strategies for optimizing carb intake to enhance performance, such as timing, types of carbs, and portion sizes. Address common misconceptions about carbs and athletic performance, and tailor your advice for [SPECIFIC DIETARY PREFERENCE, e.g., vegan, keto, or gluten-free] athletes. Use clear, actionable language suitable for both beginners and advanced athletes.