Any object that brings about tumult in the emotion, that is an object of desire by which you either want it intensely or hate it intensely. Intense wanting and intense hating will affect the emotions. The test of good health is freedom from emotion, correct understanding without any kind of ebullition, burning desire of any kind. This is briefly the definition of desire. There are two kinds of desires, anabolic and catabolic.
Anabolic desires are constructive, helpful and necessary for maintaining health and peace of mind.
Catabolic desires are destructive in their nature. They throw the energy out. Any procedure by which we can conserve our energy is anabolic. Any process by which we deplete our energy and then become weak, that is catabolic. One must be able to very carefully distinguish between one and the other.