There are several kinds of acne. The kind that you get when you hit puberty is not related to diet. Adult acne in most cases is however.
The thing is food does not directly cause acne. The logic is pretty simple actually. Acne causing bacteria grow in blocked pores and greasy food and dairy makes me super oily . More sebum more blocked pores aaand more acne.
Sorry I guess I generalized too much. I definitely get super oily after eating dairy It might be that some people have my skin type. I've noticed some of my friends dont get oily at all after eating a ton of pizza. Depends on the person I guess. As for the snake oil thing their treatment has already worked for me so if you have acne I would advise giving it a try.