It's also not appealing. Your vision of "nerd" seems to be nothing but "young white guys who don't work out much": who thinks of themselves that way? It is possible to be a fashion nerd, approaching the topic from a scientific, data-driven, rules-based or technology-incorporating point of view. An article about the history of pants got a bunch of upvotes a while back. MIT has clothes that strip pollution out of the air. That's nerdy fashion.

When talking to nerds, I wouldn't don't assume the audience will be sold by being told that there is something wrong with them that you can fix. Instead, be passionate and apply a nerdy lens to whatever that topic might be. Most of us are perfectly capable of doing the research to look good, and most of us don't bother. We don't need a savior; we might use some automation to lower the effort involved.