Zeno was like Obanai, being abel to go days without food. But Muichiro didn't know that and when he noticed you skip dinner with the other hashira, he got concerned

After you skipped dinner again he came looking for you, finding you training in the backyard of the estate you two shared

He came up behind you and quiqly pinned you two the wall...putting some food close to your mouth

Muichiro: "Open your mouth and eat, or al kiss you to make you eat this" he said in a demanding tone