It is not that simple sadly. Anorexia is a disorder therefore, to get the proper help you need to stop you need to seek professional medical attention. You can try to just stop but that is extremely difficult. To stop you need to probably go through therapy in order to convince yourself that there is nothing wrong with you. This is because people who typically have anorexia think that they are too fat so they stop eating. As easy as it may seem to just start eating again and heal yourself over time without the proper therapy you will start to see yourself as too fat again and go back to not eating in order to compensate for that.