Hollow spaces inside
 

What causes tomatoes to have hollow middles? :?: They seem bloated and the inside flesh wall is wierd. Is there something that I can do? Is this common in some tomato varieties? Are they ok to eat and serve people?

Sounds like tomato puffiness, which is generally environmentally induced. For example, cold weather during pollination could lead to it. So could excessive nitrogen.

Yes, they are okay (safe) to eat as long as you find them palatable.