Cooked meat loses its enzyme content. In fact cooking anything kills the enzymes in foods. In order to digest such cooked food, your body has to produce its own enzymes for digestion. Your body produces diminishing amounts of enzymes with age. Eating more raw foods (such as the fruits and vegetables you mention) will require your body to produce less enzymes as they are already present in the raw food.
You can either buy an enzyme supplement containing protease (availabe at health food stores) or eat more raw foods and less cooked food.
Now if only I could practice what I preach!