Lay off the fatty “rich” foods and sugary treats (especially ice cream).
Eat whole grains and fruits and vegetables in their original state (not over processed).
Eat small amounts of meats and cook them well done (to kill parasites and bacteria).
Forget about diets. Especially crazy high protein high fat low carbohydrate fad diets.
Don’t eat like a pig.
FYI: I’m a very active 68 years old man, 5’11”, 143 pounds, 8% body fat.