You don't have to go to a doctor to be tested for insufficiency. If you have a problem digesting fats, you will know it. I always suggest taking OTC digestive enzymes because they help tremendously. I have been gluten-free almost a decade and this year, stopped using them to see what would happen. I was using them far less frequently than when first diagnosed. Low and behold.......I don't need them anymore. I am eating more foods than ever, a completely normal diet and everything goes through as it should, with no more issues eating fats! This particular problem takes quite awhile to correct as fats as just so hard to digest.