"Prenatals cancel out McDonald's" ...😑

A friend who is also due in November said this to me the other day. Literally all she eats is McDonald's, fast food and soda. She said she doesn't like the taste of water so all she drinks is Mountain Dew and Pepsi. When I gently asked her how she's getting her nutrients in she said "oh I take a Flintstone vitamin every week so those prenatals should cancel out the McDonald's". What do you even say to that (rhetorical question)? Makes me so sad.