[nyokodo]

> If my food isn't nutritious I either wither away or am forced to eat more food

Less nutrition doesn’t mean no nutrition. The vegetables are still plenty nutritious.

[giantg2]

I believe the argument they are making is that if the vegetable contains less magnesium, then you have to eat more of it to satisfy that dietary requirement (or your body's craving for it). So the vegetable still has a lot of the other macronutrients but now you have to eat "too many" of the macronutrients to satisfy your micronutrient needs.