First article - long runs without consuming exogenous carbohydrate absolutely provides metabolic benefits. The balance you have to find is that if you are going to consume carbs during a race you need to practice to know what works for you. For ultras (
@Zasada, I'm talking to you) you absolutely need to practice this, and many think you can train your gut to push up the amount of calories you can process per hour. I'm still not sure how to balance this - my thinking is that it's best to "train low" earlier in the training cycle to maximize those benefits, and then in the final 8 weeks or so start practicing the same nutrition strategy on long runs that you'll use during the race. But I don't know if there is science to support that, more just a working theory.
Second article - really interesting, particularly that map with the zones. I supplement with Vitamin D all winter and take fish oil year round, and I eat salmon about once a week. I stop supplementing in spring, so looks like I've accidentally been doing it right.