On the Positive Weight Control list, a common topic is how to reinforce the good habits they are working on. As one member said, to buy something for himself or to treat himself to something is, in effect, depriving himself of it in order to use it as a reward later. That just isn't very positive! One of the strategies list members have had great success with is to click or "tag" the desired behaviors and make collecting the tags reinforcing in and of themselves.
One list member gives a certain type of coin for every tag he earns, and he puts those coins in a glass jar. He started out thinking he would use the money to buy something special, but he has found that watching the coins accumulate is more reinforcing than what the coins will buy. Another list member suggested putting stickers in a book, much like the stamp books that were popular years ago.
Another list member has found that by using variable reinforcement, she has made the process of earning tags more reinforcing. When she does a desirable behavior, she tags it, and then rolls a die. If she rolls an even number, she gets to reward herself with a token. The variable reinforcement has really motivated her to work harder. If she rolls an odd number, rather than be disappointed, she looks for an opportunity to perform a taggable behavior so she can roll the die again.