I often will vomit after eating meats that are cooked in their own juices, can't eat gravy or anything high in grease, garlic or fat. why?

May be stomach or : Gallbladder. If stomach is inflamed/ulcerated, fats can stimulate more acid causing more irritation. Fats can also exacerbate reflux. More likely is gallbladder problem: gb stores bile & secretes it to help digest fats; fats cause it to contract. May have gallstones or reduced gb function or gb inflammation. See pcp for evaluation, tests, options for treatment. In meantime, avoid fatty triggers.