It’s fair to start by looking at animals to remind us that satisfaction is primarily a product of nature-creature interaction.
The priority of all the creatures on Earth, including humans, is to increase the odds of survival and reproduce. We are programmed to feel satisfaction when our odds of survival and the prospect for reproduction increases. Eating is supposed to be a pleasure because it provides essential nutrients to maintain life.
However in nature, there is more pain (predators, harsh weather, disasters, diseases… ), and less pleasure: food is limited and has to be fought for, and reproduction can cost your own life.
Conceptual State of Animals in Nature
Unlike humans, animals don’t have the capability to alter nature to their favor. If they were to reduce pain and increase pleasure, the only tool available to perform the task would be their own bodies. They always stay alert. (Some animals even sleep standing up.)
Once needed, they immediately mobilize their abilities to their maximum, whether it’s sensory (e.g. smell), physical (e.g. run) or cognitive (e.g. vocal communication.)