User blog comment:Mythical zoan fruit enthusiast/For those who want Luffy to have Mera Mera and Gomu Gomu/@comment-9101417-20130504201005/@comment-195.241.127.96-20130509212309

The same as luffy body being able to bend and expand at will?? So what you are saying is that when someone has eaten a fruit that can change the body structure of the user he can just eat another devil fruit.. i disagree. I don't think that a devil fruit changing body structure counts. And it's not just A change in body structure. There is more to it.

When Nami was talking to Zoro and Luffy about blackbeard she used the word "HE" when talking about blackbeard. Then Zoro and Luffy reacted by saying: it's not "HE" it's "THEY" because Zoro and Luffy probably felt that blackbeard was not ONE person or one mind or whatever that makes him able to use a second fruit. it's not just a devil fruit like Luffy's that makes  your body structure strange in anyway like you are saying.