The good part is that (unlike people) it is a LOT easier to get your pets to loose weight.
If we had someone controlling our diets and how much we eat and we couldnt get snacks, we would find it much easier to loose weight.
So just cut back on feeding and feed less fatening foods and let him walk around a lot more. The same as people.
Portion control
I would still feed him everyday at first, but cut his portions in half. Then in a couple of weeks, try feeding every other day, but the same portions (half of what he used to get)
as well as letting him get out to walk around.
Dont let those puppy eyes get the best of you.
He'll shed the pounds.

Just make sure he's not shedding weight TOO fast.