This is a very important point. All my nutritional research has been for the purpose of manipulating body levels of chemicals through diet. The chemical changes due to stress or emotions are faster and occur all the time, not just in response to food. I am convinced that emotional "diet" is as important as the food "diet". I even considered trying to classify emotional responses or at least internally generated chemicals into my nutrition book, but decided that this wasn't really nutrition, but something else.
My expanded environmental "nutrition" was going to include air-pressure, heat, emotions, sleep (two kinds!), exercise, mental stimulation, sunlight/light, and some other environmental factors affecting health. I almost included these in an appendix, then decided that I could expand these into an entire book, and then never got around to it.
Maybe "time" is an essential environmental factor?
Harvey Newstrom <mailto://firstname.lastname@example.org> <http://newstaffinc.com> Author, Consultant, Engineer, Legal Hacker, Researcher, Scientist.