Artifacts from Mental Space

Advice?  Mal pretty much can't sit still and eat.  We force him to sit with us at the table for dinner, but because he gets antsy the minute his ass hits the chair, we don't make him sit long.  This means he doesn't get dinner.  On weekends, he won't sit to eat lunch, and he never sits to eat breakfast.

I've taken to setting a plate of finger food on the floor of his room, which he can graze off of all day while playing.

When that's not an option (breakfast, workdays, dinners out), any ideas how to get a kid to stop playing and eat?