Defecation, or a drink of water when you’re very thirsty bring you relief, but not really satisfaction.

I feel that both of these can provide satisfaction as well, though I'm less sure about the water.

I can understand the desire to minimize or eliminate the need for functions that serve only to provide relief, but I think the “let’s subsist on Soylent” people are throwing the satisfaction baby out with the relief bathwater.

Or they just get more satisfaction from other things than eating.