There's that, and ~75% of corn and grain grown is used for feed and ethanol.

What do you count as thrown out? When I cut the hard stalks off of broccoli that makes up a significant percentage of the food by weight. But they aren't really edible anyway.

If I lived on a farm then I would feed all the food waste to pigs, then eat the pigs to achieve near zero food waste. Just like my uncle used to do. But I live in a suburb and my neighbors don't appreciate pigs (or compost piles). So anything we can't eat goes in the garbage.

I will save a gallon ziplock worth of broccoli stems in the freezer (dice before freezing) and then turn them all into broccoli cheddar soup when the bag fills up. I’ll buy one crown of fresh broccoli to get some florets into it.

Broccoli stalks are perfectly edible and nutritious, they just aren't conventionally used in many dishes. I sometimes make hot pot where I include the stem as well. Another cultivar of the same vegetable becomes the kohlrabi, where the stem especially is used.

I started composting last year and combined with bottle return (takes 5 mins once a month at the grocery store) it's amazing how much waste and recycling I've been able to reduce. My next goal is all but eliminating my plastic use, through refill stores, laundry sheets (not pods!) and the like. It's not actually that hard to reduce our individual impact, just requires unlearning some wasteful habits!