The Noam Elimelech explains that the way a Tzaddik needs to sanctify himself through food, drink, and money is even greater than his sanctification through Torah. Why you might ask? Because the Torah is already holy and the dark side doesn't have much sway in the realm of Torah. Physicality on the other hand is rife with challenges of the dark side, and so, through proper holiness in food, drink, and money, one can greatly sanctify himself. [update: for the record, The Noam Elimelech says specifically that this is true of the Tzaddik, but for the rest of us, the avodah we do in our tefillah and Torah is more important.]
The Baal HaTanya actually gives us a hint as to how to draw close, as simple beinonim, to the level of the Tzaddik: By delaying (for even a short while) our desires for things which are permitted to us, we can make ourselves a little bit holy, and in exchange we are aided with much holiness from above, so much so that eventually we will even be able to push off the yolk of the dark side entirely. For those keeping score, that would mean we would be able to reach the level of Tzaddik.
update: we mentioned in the past something from Rav Steinsaltz that is relevant here as well, about berachot being the perfect oppurtunity to delay just a little our desires.