Problem: Claire runs cross country in college, and lately, her times have not improved. She knows she needs adequate carbohydrates to keep her body fueled. Typically, her food intake consists of cheese sticks and a glass of orange juice for breakfast; a peanut butter sandwich, apple, bag of pretzels, and sweetened tea for lunch; spaghetti with marinara sauce, garlic, bread, salad, and a glass of milk for dinner; and orange for her evening snack. Lately, she is feeling tired and has to wear a sweatshirt in class to keep warm. She is also having trouble concentrating. What do you think is causing Claire's problem, and why? What would you recommend?