i'm the minority, but I do believe that mike might just be natural, or at the most, someone who uses insulin (who some still consider natural).
Partially because of his genes, which are very good.
Mostly because he brings up God so frequently when citing his reasons for being natural. No one would be crazy enough to anger the Lord that much by lying using his name. Mike has a religious tattoo also, I believe. I just cannot see lying about it like that. Unless of course, he believes that insulin is a natural medicine (maybe he's a diabetic?). WHo knows...