My thought is that you need some more fat to supply calories, but you have the problem you mentioned with fats. Have you tried using a digestive enzyme to help with the digestion of fats? I do not know of any specifically, but maybe someone else can chime in here. A Google search may help. I would try adding whatever type of cheese you can tolerate to eggs. I would include small amounts of avocado since it has a high FP in quantity. Cream and butter would certainly add to your calorie count as would olive oil. Can you tolerate gluten? French bread has a low FP, and is great with butter or olive oil. Lactose free (Breyer’s) or soy ice cream (Trader Joe’s has one) would add to your caloric intake.