Erwin Schrodinger's What is Life? Just reread it after 20 years or so.What an organism feeds upon is negative entropy. Or, to put it less paradoxically, the essential thing in metabolism is that the organism succeeds in freeing itself from all the entropy it cannot help producing while alive.
serendipity. i have been meaning to submit this to hubski https://www.quantamagazine.org/20170126-information-theory-and-the-foundation-of-life/Even simple bacteria move with “purpose” toward sources of heat and nutrition. In his 1944 book What is Life?, the physicist Erwin Schrödinger expressed this by saying that living organisms feed on “negative entropy.”
Not my job. :) The point that Schrödinger makes in that essay is that it is not 'energy' that living things consume, but that we find streams of negative entropy into which we dump the entropy that we produce. It is this quality that he suggests is essential to the differentiation of living vs. non-living. The book contains his thoughts on consciousness as well. He dismantles the Western view of individual consciousness, and the existence of senses. Good stuff.