Sorry man, you can't say he has the same body in
Equilibrium,
Reign of Fire,
The Prestige and
3:10 to Yuma. (Pics attached, click the links)
The guy said countless times he hates working out so it's obvious he won't do it for roles that don't require it (Prestige, 3:10) in which he has his "normal" body. He even looks a little puffy in The Prestige actually.
It's obvious he worked out for the other two (RoF and Equilibrium), very obvious. No one has a body like that just "normally". Sure he looks nowhere as big as he is in Batman Begins, but I could sure deal with a Batman the size of Bale in Equilibrium.
Now I will concede the pic showing him in TDK wearing his black t-shirt and sitting next to Alfred makes it clear he is not as buffed (shoulders especially) as he was in BB or even Equilibrium. But his arms make it clear he has indeed hit the gym for TDK, just less than when he shot Reign of Fire, Equilibrium, Batman Begins...