external or internal motivation. External motivation stems from external factors. You can be rewarded with recognition and praise if you lose the extra pounds, and the punishment in the form of, for example, the feeling of humiliation or exclusion from a community motivates you to stay on track.
External motivation can be a great kickstarter for weight loss. For example, reporting to a personal trainer can be motivating, because it might feel a little humiliating to present a diary of cream cakes and sodas. You will probably also want something out of all the money you have given for the training. But