A thing is not necessarily a good simply because it is necessary. We degrade the meaning of the term "good" when we apply this title to bread, barely, and the other commodities without which life cannot be sustained. The Good is in every case necessary; but what is necessary [for mere life], is not in every case good, since certain very paltry things are indeed necessary. Nobody is so ignorant of the nobility of the title "good" so as to demote it to the status of trivial utilities.
Seneca, Epistle 45
Mere survival is not the purpose of the Stoic's life. Life is not an end in and of itself. It cannot be. Bacteria lives. Pigs who lounge in their own filth and dogs that eat their own vomit live. The criminal and the murderer, the libertine and lustful, the selfish and angry, the coward and the impious - these also live. It is not enough for a man simply to live, but to live well. For the Stoic, living well does not consist of living long or being constantly satiated with the things that make for longevity - and much less in base pleasures, comforts and luxury! A life lived well is a life lived nobly, virtuously, piously, free of Vice and Passion.
To call food "good" is to have a false notions concerning the Good Life. Do we not sometimes reject food when Virtue demands it? Sleep, too, is necessary for mere living, but sometimes sleep must be sacrificed for good living. We willingly in certain situations suffer the cold, the heat, and various discomforts for the sake of what is morally right. Many men - brave souls and heroes! - have even sacrificed their lives altogether for the sake of living life well. How can we, then, call anything "good" which we at times easily spurn for the sake of something else?
The morally necessary trumps always the physically necessary. Only the Good is truly desirable and only the Virtuous is truly good. These other things, our "bread, barely and other commodities", while they should not be rejected to no purpose, ought to be recognized for what they are: objects that, depending on how they are utilized or esteemed, can be used as much for Vice as for Virtue. We debase the title "good" when we apply such a noble word to what can be used for its opposite.