Why do certain vegetables shrink so much when cooked

Question

I am (at least I would like to think) a better than average home cook but I still can’t wrap my head around why vegetables shrink when they are cooked. I know some like kale let out water but what about ones like onions and mushrooms that seemingly don’t let out water?

In: 5

Answer 1

When you cook them the plant cells burst and lose water and collapse. Imagine a bunch of water balloons glued together, and you pop half of them. The overall shape will shrink down a lot.