Actors and actresses gain and lose all the time. I read in that picture that is lurking around here some where where he is knelt down, in the caption it said he was working with a personal trainer for some martial arts movie I think that could also be it, either way he isn't is big as he is in the Cyclops suit I know that and part of it was the definition in the suit itself, although really he needs no help. But I don't think he could weigh over 140, and if so..... it's barely.
P.S. Could you imagine him with the facial hair like that and the Cyclops glasses. LOL