I just read Michael Pollen's "In Defence of Food" and it is so simple:

1) Avoid high fructose corn syrup, and items with non-basic ingredients.

2) Take Omega-3 if you don't regularly eat fish (and B12 if entirely vegetarian)

3) If a boxed product features a prominent health claim, it's probably bullshit.

In the past month of "eating" healthier, I have noticed more stability in my energy levels.

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About three months ago I stopped combusting/smoking (plant vape only) entirely, and my blood pressure dropped -20/-15 , leaving me almost "back to normal" range.

Not smoking has so far been a more-immediate health increase, but I'm sure the food intake changes will amount to something.