I can’t remember the title/author of a short story or novel in which real food is scarce and illegal to have. The main character secretly grows vegetables and raises rabbits for meat. There is something about obtaining Quicksilver which is key to him connecting with a secret organization that wants to start the world over and recruits talented people like him (because he has farming skills). I recall a passage where he is having a meal with another person eating govt approved food, and she is described as obediently chewing down the rubbery morsels, or something close to that.
I most likely read this in the late seventies. It might have been in a book of Sci Fi short stories or a short novel either laying around my house (lots of older siblings with books) or in a teacher's unofficial lending library. I have no recollection of any cover/art. Things I can recall about the story: The main character is an adult but young; I think he learned his love of food and skills raising it from family that is no longer alive; he meets a young woman who becomes a possible love interest - that is whom he is with when he eats the govt food. When he decides it is safe, he feeds her a real meal at his home and she bursts into tears at the pure novelty and enjoyment of the flavor and texture of real food. Also going on is the sense that he is being watched/followed and is worried about getting caught and prosecuted for his food habits. In the end it turns out the people watching him are the resistance who are planning to move to a new place (?sketchy memory here!) where a civilization can start anew without the current regime's restrictions. They have limited capacity so are choosing candidates carefully. The main character does come to the attention of authorities, and is in danger of being found out and stopped before he is claimed and rescued by the new organization. I can't remember any details about the revelation and the transport, other than a vivid scene where he is in something resembling an elevator where something very strange happens. Other people in the vehicle that are not in possession of the quicksilver thing and not chosen by the resistance do not survive the experience. There is a detailed description of how the light changes and how it affects the appearance of other people in the "room", especially a woman antagonist on board with him. Something about the outline of the makeup on her eyes becomes illuminated. The story ends on a note of potential hope. The main character did not seek out the resistance, is somewhat wary and skeptical about its existence and the feasibility of its mission, and eventually follows their instructions to join them only when it becomes clear that he is about to be nabbed by the authorities.