As a small time backyard gardener I can say from experience that 4 plants made more cherry tomatoes than I could reasonably eat. I was giving ziplock bags of cherry tomatoes away to people at work for a couple months. They probably did produce a year’s worth of cherry tomatoes, but they don’t refrigerate or freeze particularly well and they’re not a great choice for making tomato sauce because of their liquid/pulp/skin ratio.
Similarly I’ve found that I can grow a year’s supply of red pepper flakes with a whopping two cayenne plants. The rate at which I consume red pepper flakes, I’m about out by the time this year’s peppers start ripening.
I’m able, in my tiny little garden, to grow more of single kinds of foods than I can reasonably eat. I cannot grow enough to sustain my entire diet; I’d need more land than I own to grow grain.