Jell-O
Gelatin is an interesting thing; it can solidify liquids and turn them into Jell-O. Surely something as innocent as gelatin can’t be that bad, can it? It can if you don’t like animal skin, tendons, ligaments, or bones. They boil the carcasses of pigs and cows to get gelatin.
Not precisely unhealthy, gelatin is still not something you want to put in your body.