Hello~Usually the fatigue comes from a type of allergy or sensitivity to the offending food. Most red meats have chemicals in them, you could be having a reaction to them. Try to avoid foods that make you tired, then when you start feeling better add them back one by one, see which ones cause the most fatigue.
Yes, you can certainly feel that way from a sensitivity. Aged foods remind me of sulfate and avocado can cross react with latex .. just some thoughts to ask your doctor about maybe.