If you’re looking to peak in a competition, you can clean up your diet and shed some fat, but if not, don’t worry too much about it for now. Fat affects mainly your relative strength by incresing more body weight. I doubt you’re fat enough to restrict range of motion.
However, for your health and energy and all, it would be nice to clean up the diet. There’s difference between gaining weight with junk food and gaining weight with lean meat+whole grain+fruits+nuts and seeds (veggies are healthy, but they don’t really add much to calories).