There’s a second, hidden hunger bar called “saturation” which controls how quickly hunger decays. Some foods provide more saturation than others. For example, melons are easy to farm, but provide little saturation. Bread and cooked meats tend to provide decent saturation.

This mechanic isn’t new though.

Maybe you are getting a lot of dmg. In order to heal you need a full hunger bar. And healing depletes your hunger bar fast.

There's also a hidden second hunger bar. You need higher quality food to fill that one. Maybe you are using lower quality food now.