It's really not. Who sits in a pool in Vegas drinking and smoking when their supposed to be getting fit for a world cup.
Plenty of examples like this over the years
He apparently had the lowest body fat percentage at Utd for years, so I think it's myth.
He might let it go a bit too much in he off seasons, but he's always where he should be once the season starts.
He's played in over 40 games near enough every single season since he broke through with us as a teenager, 55 one year for Utd, thats not including his international appearances.