YSK: Ordinary white mushrooms are amazing sources of vitamin D and protein in your diet and cost next to nothing. If you're cooking with ground meat, you can mix in chopped/processed mushrooms to cheaply increase the size of your meal without changing the taste.
from /r/YouShouldKnow
YSK：普通的白蘑菇是你饮食中维生素D和蛋白质的惊人来源，而且几乎不花钱。如果你正在用碎肉做饭，你可以在切碎/加工过的蘑菇中混合，以便宜的方式增加你的饭量，而不改变味道。