Is eating processed food bad? Or regular food.?

Such as eating steak it has a lot of fat, BUT its animal meat. Does that have to do with anything bad? What about tuna? It has a lot of Cholesterol BUT its a fish thats not prosessed. What about pecan? It has tons of saturated fat, BUT its a nut, its raw and healthy and not processed.... does any of that affect weight, muscle gain, or health? would it affect people? would it affect me? im 14 male. 140 pounds, 65 inches tall.