Surgery Bed While Recovering From Surgery In Bed, I've Put On A Few Pounds. It's All In My Belly. How Can I Lose It Fa?

While recovering from surgery in bed, I've put on a few pounds. It's all in my belly. How can I lose it fa? - surgery bed

Another important factor is a leg, had a rod inserted. Can not run or something. :) I'm on crutches, however.