Zorba dispenses health advice to callers in an engaging and accessible way, while Tom, uh, well, I've never been able to figure out why Tom is there, other than to occasionally set up Zorba with the "typical lay-person's point of view" follow up question. They have a goofy chemistry; Zorba is elfin and spry and always upbeat. Tom is a bit of a curmudgeon, but never a downer. One thing for Zorba is that he has a pretty finely tuned "B.S." detector, and they often talk about fad diets, home cures, etc. These are often the most interesting part of the show.