Being a life-long Catholic, I grew up giving up some treat every Lent. Usually this was something I enjoyed and knew I was going to get back at the end of Lent. As an adult, I've grown out of the habit.
Now during Lent, my family and I try to give up something negative (like a bad habit) and often replace it with a good one. This is very similar to what SP advocates and seems similar to what you are doing.
For this Lent my family has decided to give up two bad habits: Saying unkind things to one another and about any person; and cursing among ourselves (we have two teenagers). Each individual family member has also decided to give up a bad habit. For example, my youngest son loves tipping back in his chair during meals. We are concerned for his safety and the furniture. So he is working to rid himself of the habit.
As an incentive, we are fining ourselves for every offense we commit. We are donating that money to our parish's Operation Rice Bowl, which benefits Catholic Charities.
Perhaps you could "pay yourself" for every day you stay off the scale. Then in 6 weeks you'll have a tidy sum of money to spend as you wish.
FYI: You may know that there is a Catholic Critters SP Team. I belong to it and you can find the link on my page. There is a Lenten challenge if you are interested.
Good luck in your personal challenge!
"You cannot accept another with a hateful heart. You cannot hear the other with a closed mind. You cannot embrace with closed arms. You cannot shake hands with a clenched fist."
--Indira Priyadarshini Gandhi
| current weight: 149.0