Low-cal treats: Do you have a favorite?

When I was a kid, the prescribed method for entertaining your dog while away was to toss them a soup or rawhide bone. But those can present problems to some dogs. Soup bones can chip and be swallowed. Rawhide is tough to digest. Bully sticks are great, but, as with the rest, if you use them, you need to be around to supervise.

Kongs and various interactive toys where you can hide treats are nice, but I'm finding that the peanut butter, cheese and treats I stuff into them can create dietary problems. Especially when you've got a dog on the injury list with no outlet for his energy. I've cut Eddie's food portions, but I'm afraid he's getting too many calories.

Do you have any low-cal treats you stuff into your Kongs or interactive toys? Do you have any other tips for keeping your dog occupied while you're away without making them fat?