I know that feeling, but not from an entire meal of foie gras.
The beginning of my career as a "foodie" involved cooking my/our way through Julia Child's volumes of "Mastering the Art of French Cooking." This was the true classic old French cuisine, and the problem with it was that you could go through amazing amounts of butter and cream. I can't recall specific menus but I know we really liked Coquilles St. Jacques -- in which the scallops are embedded in a cream sauce, and packed into large scallop shells, and studded with butter, and browned in the oven. And we really liked the Supremes de Volaille recipe which involves taking boned chicken breasts and mushrooms and cooking them in heavy cream. And some of the chocolate cakes had four sticks of butter with another stick for the icing. Put those together with a little foie gras and you have a real kick in the head.
I didn't exactly understand it back then, I suppose in my early thirties, it seemed like eating the tastiest food in the world should make your body feel good, but instead I would flop on the sofa and moan quietly... It wasn't until about 10 years later that I got my cholesterol tested and realized that I was exacerbating a situation that was bad to begin with. I could be a lettuce only vegetarian and have shockingly high cholesterol. And eating a "Julia Child Dinner" basically turned my blood into sludge.
So I know I wouldn't do it again, and I think that maybe I would be on Rahsaan's side of this discussion. You can make some awfully tasty dishes based on lentils or whatever, without using a pound of butter, and you can feel good both while eating it and afterwards.
But OTOH when I'm in Paris and I see foie on the menu (and one sees it everywhere) I order it.
F