In Sefer Keser Shem Tov the Baal Shem brings in the name of Saadiah Gaon that it is proper for one to learn from the desire for physical things how to desire avodas Hashem and His love.
We know from nearly all works of Chassidus and Kabboloh that Hashem completely fills all the worlds and surrounds them, and there is nothing other than Hashem. So we could ask a question on the Baal Shem, “What do you mean to learn from desire for physical things to desire avodas Hashem? Isn’t it all the same?”
The answer to this is that ultimately it is. Rebbe Nachman says in Likutei Moharan that one who eats properly and defeats the desire for improper eating gains a greater perception of the letters and light contained in food. We can say from this, that such a person would reasonably gain a greater perception of these things in other pleasurable things as well. All forms of pleasure, outside of direct avodas Hashem such as davening and learning Torah, or eating on Shabbos in which all food is holy, are in the realm of Klippah Nogah, the Shining Husk. The Klippah is the shell containing the holy spark, which is released through a Jew utilizing that thing for a holy purpose. When the food is realized to be a utensil for the purpose of making a brocho to thank Hashem for His goodness, and the brocho is made in such a way as to bring Hashem’s Light into this world, as described in Pri Etz Chaim, then the Klippah is broken and the Netzotzos HaKedoshim (Holy Sparks) are released to return to their Source. Through having desire for physical things, and elevating this through learning how to love Hashem and love serving Him, thereby breaks the Klippah surrounding those pleasures and returns them to a state of holiness.