It takes a lot of work, food and gear to get that size - your body hates to be that ineffecient (it sees it like dropping a V8 in a Chevette!)... and it takes a lot of calories and brutal training for your body to even begin to accept a lot of muscle weight... and being lean - low bodyfat at any weight to your system means possibility of death from starvation...
If you stop feeding it the stimulis it needs - bye, bye muscle. And if you keep eating like you did - hello fat!
I wouldn't call them "normal" - they are still athletes in good shape IMO...