I do not like this kind of bet. A bet that no money nor anything is involved. I mean nothing is involved because one of you can decide not to fulfill the betting promise. Example is if your friend did not lose more weight and still decide not to pay for the meal? This can happen. I do not bet with people. I prefer to go to casino or bookie to bet instead.
Sometimes some folks do set a certain amount of money in such occasion just to make things more exciting, that whomever gave up first will pay the other , so with money on the line both parties will have to take the challenge serious till they finally hit that target goal or until one endup given up and paying the other .