"My cooking has improved since being home."

So he did have a few things at home, but it wasn't really anything to brag about. He's mastered putting rice in the rice cooker, he learned how to make eggs, and things like sandwiches and cut fruit are easy. He can boil vegetables too (though he doesn't always get them right, so they're usually either underdone or soggy mush). He usually buys things like "hot-and-ready" chicken or other ready-made meals from the store between that. It's enough to survive without poisoning himself or eating out every day, anyway.

"I haven't gone shopping yet today. During Cordis, I go through significantly more food than normal. I eat more like Murasakibara."

Okay, it's not quite that bad. It's more like Kagami, but Midorima refuses to compare himself to Kogami. Murasakibara is slightly less infuriating, if only because he lets Midorima nag him like a bossy parent all the time with only minor whining.

Regardless, all he has left in his fridge are birthday leftovers anyway, since he got spoiled on his birthday. They need more than sweets for sustenance.