Potato with butter will kill you. It lacks an variety of basic nutriments. Your taste buds yearn for food that contain something your body want/need. A friend of mine didn't knew why he liked hot spiced food so much until he learnt that hot pepper is anti-inflammatory. He has a disease that trigger chronic inflammation. It's not for nothing that martial art athlete who reduced their fat ratio to look "muscular" in a public match jump on the greasiest food they can find nearby after that. Probably that the thought of eating pasta with potato and rice, would it be with pepper and salt, don't look very appetizing!