Popeye was created during WW2 when there was rationing. The idea was to get kids to eat spinach which was cheap and plentiful. Never a fan of the canned stuff, but fresh It's pretty good.
Spinach is full of Oxalates, Lectins, Phytates, Goitrogens and Anti-nutrients. It's poisonous. And that's without talking about the chemicals they spray on it as well.... Carnivore Diet.