Carbohydrates or ‘carbs’ are an energy source in food that comes from starch, sugar and cellulose. Carbohydrates provide vitamins, minerals, antioxidants and fiber in the diet. The current recommendations suggest 45 to 65 percent of daily calories come from these types of foods.arbohydrates or ‘carbs’ are an energy source in food that comes from starch, sugar and cellulose. Carbohydrates provide vitamins, minerals, antioxidants and fiber in the diet. The current recommendations suggest 45 to 65 percent of daily calories come from these types of foods.