Is it normal my friend eats like this?

In my opinion my friend, who is 25 years old, eats unreasonably slowly. He takes an hour and a half over his evening meal (two courses), will eat a small, celebration size chocolate in three bites, will dissect everything he eats to pieces and will only eat one part at a time e.g. when eating cake (eaten practically crumb by crumb) he will eat around the icing and leave it all to last then eat it all at the end. He also prefers circular food such as burgers so he can eat around the outside, keeping it circular all the way to the middle.

I have a history of eating disorders and have only come across this kind of behavior in the unit I received treatment in. Its not something I ever did though. He would never cope with the 45min time limit in there, he would go crazy. Am I just being over sensitive to this or is it as odd as I think?

He says he eats this slowly because he has taught himself to as a way of controlling himself and he is savoring the flavors (he was overweight and has lost around 10 stone, going underweight himself at one point).

What do people think?