PhotoperiodEffect.com

9. It's the (fast food, white flour, sucrose, extra fat, hydrogenated fat, high-fructose corn syrup, low vitamin density in modern vegetables, monosodium glutamate, toxins in the air, etc, etc – pick one or more) dammit! No need to get strange and look at light, which we don't even eat.

The first difference is that you can reverse the effects of too much artificial light easily enough and see the results without waiting for a few years. You'll see changes in appetite, weight loss, skin, blood sugar and blood pressure. We already know that sleep hygiene is extremely important for all those health indicators and more (manic depression for example.) Make sure that your sleep hygiene includes plenty of uninterrupted real darkness and see the difference. It's harder to, say, remove the minute amounts of toxins in the air, and merely eliminating all high-fructose corn syrup or hydrogenated fat from your diet (both very good things to do) won't act like a magic wand either. I did these things (and most of the rest of the list) years ago, with marginal results, but more darkness (and maybe more sushi, which I introduced at the same time and don't want to quit) has made a revolutionary difference in my life in a short time. (Just the sushi doesn't work, though, I know that from experience now, too.)

Second, it's very true that there are many protective factors for modern chronic illnesses like diabetes and multiple sclerosis; such as being breast-fed, Vitamin D, genetic makeup, exercise, reducing fat intake, and far more – just today, as I'm revising this section, a new study has come out showing that curcumin (from turmeric) and phenethyl Isothiocyanate (from some vegetables) reduce prostate tumor growth in mice, and there are endless other similar studies about pomegranates and tomatoes and on and on. Paying attention to these does make some difference in fending off or helping to control the severity of chronic illnesses.

Equally and oppositely, there are are many factors that increase the risk to some extent, and any or all of those you've mentioned (plus plenty more) might well be helping to increase the risk. That's not in dispute. But it's all but certain that none of these are the whole story or anything like it – quit any one of them and your extra appetite and midriff love-handles won't melt away by themselves, or eczema simply disappear, your mood lift or daily energy dramatically increase, your blood pressure drop, etc., without further effort. But all this has been the case for myself since I've adopted a natural day with constant, longer and darker nights, and this is consistent with the research I've seen.