Helping one another
Two weight-loss buddies can help one another. One can talk the other out of eating a snack, or into going for a jog.
They can give spiritual support to one another. If a person eats fewer calories than he needs to live on each day, his body will use the stored fuel (fat). If a person exercises more than he did before, but does not start eating more calories, then his body will also burn up fat.