Of all the things that could POSSIBLY go wrong with human health, nutrition and the epigenetic ramifications it has should probably be among the first things suspected, along with infection and toxicity. Why it isn't that high on the list for sufferers and their physicians is a subject for more knowledgeable writers than i am....
But no -- the medical industry would much rather hunt for chimaeras than rabbits. And many patients would much rather consider themselves the prey of a mysterious disease process than come to the conclusion that their favorite foods (and other lifestyle choices) are causing their degeneration. They'd rather take a pharmaceutical whose list of side-effects is as long as your arm, than even TRY taking grains out of their diets or give up their nightly Ben & Jerry's fix.
There's a reasonable chance that people resist the idea that changing their diets could improve their health because they've tried many other alterations and found them worthless. I wish i could remember where i read this idea, so credit could go where it belongs.... It makes perfect sense that if Joe switched from french-fries to baked potatoes and fat-free sour cream, and it made no difference either in how he felt or how his blood-test turned out, he might be skeptical about switching from potatoes to turnips, as a "frinstance." Certainly, if he followed mainstream health recommendations over the last half-century, any changes he made would have had little impact on his wellness, or his subjective sense of it. If these "common sense" changes didn't help, why would Joe be inclined to try something that his conditioning would react to as illogical?
Poor Joe -- he believes that dieticians actually know what they're talking about when it comes to food -- they're SPECIALISTS, aren't they? When it comes to weight-gain, it's all about the calories, and for health, it's vitamins, minerals and antioxidants. Moderation in everything! All saturated fats are alike, and BAD. Macronutrient, schmacronutrient. How cells in a petri dish behave is exactly how they do in the body. Mice are excellent subjects, because their little bodies behave just like people's do, with a very short lifespan to allow us to see changes quickly. [sigh]
There are libraries full of anecdotal evidence as to the efficacy of food to healing. "Science" loves to pour scorn on this kind of information, because it doesn't fit the cookie-cutter notion of "HOW science works." But for the n=1 seeker after health, this is probably the best place to start to work. THIS worked for a sick human being. THAT may have worked for a knockout mouse, but is of questionable applicability if you have only two legs and the chromosomes that Nature gave you.
Of course, conventional sources of "wisdom" don't want you to try to improve your health by means of your diet or supplements. They want you to come in for blood tests, then tell you your values don't suggest that you could be short of things like B12 ... but an antidepressant might make you feel better! :-P
Our bodies evolved to be self-repairing. IF one had health as a teen but in the 30s developed infirmity, the first thing to ask should be, what has acted upon this organism to make it go wrong? In the absence of toxin, infection or injury, most of what acted upon the body was NUTRITIONAL INTAKE. Figuring out how to reverse the harm done is not going to be as easy, and probably won't be simply stopping the damaging intake ... though it's a good place to start. The next step is to see how other real people managed to mend a problem of a similar nature.
Thank god for google; I've found many answers online. "Tried and true" beats the hell out of "might" or "may."