I agree Francis is suspicious. However, as for every case, there ARE outliers..
I'm not saying that Francis is 100% natty (afterall, how the hell would I know what is or isn't in his system?). But, if we were to find one of these 'outliers', it would most likely come from a country such as Africa. Those guys have the best genetics for aethetics, where they can eat and eat all day, get big, all while keeping the fat storing process to a minimum.
To gain size you need to create an anabolic environment, which is done with a caloric surplus. In an anabolic environment, both fat and muscle are created (always!). Now your average typical human being, assuming he eats clean, works out properly, and is at around a 500 caloric surplus everyday, would typically gain around 70% muscle, 30% fat. Maybe those numbers are a little lower, say 65 and 35. This is the case for the majority of humans.
Your extreme outlier however, is not your typical human being when it comes to the properties of this anabolic environment. His body will be able to skew the results much more drastically, up to the point where he may be building 90% muscle and 10% fat in his caloric surplus. Those are some pretty impressive numbers, and that's why you see those Roman god-like physiques from time to time.