FWIW, Iceberg lettuce is surprisingly low on nutrients. It's like empty calories without the calories. Romaine is better.
I learned this during a project at school. We were using
linear programming to design a diet that met all recommended nutritional requirements while minimizing calories. I mistakenly relied on Iceberg lettuce to compensate for all the other junk food and the computer came back recommending eating [[something like)
two tons of Iceberg lettuce to get all the necessary nutrients! LOL!