What is the legal definition of food in the United States?
Particularly, in the context of food, food products, food industry, food additives, etc., what is a precise, formal, legal definition of food?
Some references to potentially useful sources, and some discussion:
Federal Food, Drug, and Cosmetic Act (FD&C) §201(f), which can be found in
21 U.S.C. §321(f) defines food, but in a tautological manner: food is used for food.
(f) The term “food” means (1) articles used for food or drink for man or other animals, (2) chewing gum, and (3) articles used for components of any such article.
21 CFR §170.3(m) defines food as (for the purposes of the subpart on food additives):
Food includes human food, substances migrating to food from food-contact articles, pet food, and animal feed.
The primary portion of this is also a tautology: food includes food. It says that 'food' includes human food, but what constitutes this human food?
(This definition serves the purpose of establishing the word food as more broad, for the subpart, than just human food, including also residues from contact substances and animal food. But I am interested in what defines the human/animal food that it refers to).
Food Safety Modernization Act (FSMA) does not seem to add any definition of food.
Dietary Supplement Health and Education Act of 1994 amends the FD&C and provides definitions for dietary supplement. The act deems dietary supplements as food, and also distinguishes them from "conventional food". But does not define food nor conventional food.
So the question is: what (besides chewing gum) constitutes food? And where is it defined?