According to Rio Ferdinand:
Fittest squad member: "Wayne or Ronaldo. They’re both explosive players that could run at the same pace in the last minute of a game as they could in the first."
So presumably he's doing OK.
Though I will say, last summer the only tabloid pics I saw of Wayne was him out jogging while he was on holiday, whereas this time he's definitely had a holiday
Which might be a good idea, if it's brought him back mentally refreshed - that might matter more than any weight gain.