There is confusion and overlap between the various value sets referenced on NutritionIntake:

DietCodes (NutritionIntake.code)
Types of Edible Substances (NutritionIntake.consumedItem.type, NutritionProduct.code)
Food Type Codes (NutritionIntake.consumedItem.nutritionProduct)
Categories of Nutrition Products (NutritionProduct.category)

NutritionIntake.consumedItem.type and NutritionProduct.category seem to overlap
NutritionIntake.consumedItem.nutritionProduct and NutritionProduct.code seem to overlap