I second that (gingernut).
Just eat the sort of foods our ancestors living in the jungle would eat, i.e. natural foods.
All this processed stuff is not what our bodies have evolved to deal with, so there is no knowing what long term side effects they will have. If folk want to put on muscle, there are ways to do that without eating foods containing unnatural chemicals, but it will take a lot of gym work.*
Reduce carbs, (sugar, potatoes, wheat, sugary drinks etc.) and increase good quality, unadulterated protein. There is a hell of a lot of hidden sugar in processed foods - one reason for the obesity epidemic. Make your own meals from scratch, then you know what is in them.
*The sort of girl/partner who is impressed by large muscles rather than your life values and attitudes might not be the best mate !