How realistic is it for countries to produce all of their own food?

I'd say it's quite unrealistic for most countries to produce all their own food, mainly because of climate and resource limitations. For example, in China, we grow a lot of rice and vegetables, but certain products like coffee or avocados just don't thrive here because of the weather conditions. I remember seeing imported avocados in Shanghai supermarkets, and they're always more expensive than local produce. That said, focusing on self-sufficiency in staple foods like grains makes sense, as it ensures food security. But relying entirely on domestic production would limit variety and could drive up costs for consumers.