What we did for him was really not Atkins per se but lower carb and over the course of a year it has worked. Just changing some of his sugary carby foods for lower carb ones has done its magic. It is almost like he is on maintenance levels:
Breakfast:
Atkins morningstart bar
cup coffee with cream
Lunch:
Packed lunch
meat and cheese sandwich on 12 grain bread
Peanuts
sugarfree yogourt
apple
Dinner:
A normal meat and veg dinner with a side of rice or potatoes BUT the starch portion would be rather small and the meat and veggies portion would be quite big.
Snacks:
Peanuts (and he eats a lot of them!)
Apples
Occasional banana
Sugarfree Yogourt
(you could also do an occasional Beef Jerky)
Eating Out:
He gets whatever he wants including the bad stuff, but if he is ordering fries, he won't get dessert for example. Or if he wants dessert, he'll just have the meat and veg during the meal.
I think when someone doesn't really doesn't want to be on a "diet," they shouldn't have to be. Not everyone can do it the tough way like we are doing for maximum loss in minimum amount of time .... Heck, if we had gotten control of our lives years ago, we wouldn't have had such a huge task ahead of us! But that's water under the bridge, so to speak.
Anything you can do today, can make your tomorrows better.