World lives off a lot of things. And is grain not produce?
I kinda don't like grain. I'm half Sicilian so its a big part of my make up. I love stuffed shells. I have a cousin who makes a ridiculously amazing seafood lasagna with pesto. I love really great bread. But I can go without that for long periods of time and get the good stuff.
My diet is Turkey, beef (which is largely free for me), seafood, mushrooms, and veggies and fruits in season. In the dead of winter, I grow microgreens indoors. It's easy, awesome, and delicious. I've grown broccoli sprouts, sunflower shoots, pea shoots, and more. It's a sandwich/taco filler or salad. Also got an indoor hydro set up for tomatoes, and occasionally other things. Got an outdoor herb garden, my neighbor's got a 100 sq ft legit garden.
I used to have a major garden like that growing up. We gave half our stuff away and it still lasted into winter. It's a lot easier to grow food than people think.
This was more or less instilled in my family when my grandparents came over in the 1920s and were hit by the Depression years later. They didn't become millionaires but they built a really good name for themselves at that time because they were able to help people out with food.