I have arguments with my girlfriend about this. She says she's concerned for my well-being because I am skeptical of most dietary recommendations. I have to con

I have arguments with my girlfriend about this. She says she's concerned for my well-being because I am skeptical of most dietary recommendations. I have to convince her that detox shakes are a scam perpetrated by snake-oil salesmen trying to make a buck off people who don't know any better. I'm not sure how to defend the latter without conceding to the former.