Oh, I'd LOVE to do that, but see about 6,000 issues with it, including consent and funding.
But it's very clear that when he eats better, he sleeps better, he feels better, he's more resilient (emotionally and physically), and as a result of better rest and improved general health, he's more able to cope with setbacks and the unexpected, is more likely to try new stuff out and generally feels better about himself.
I can't imagine why that wouldn't be true for anyone else, too.
The one thing that's perpetually made me sad since I started on the Low Carb Trail is the constant need to "prove" common sense. Even now, with my "normal" HbA1c, slimmer figure, increased energy, better outlook and general sense of well being, people still feel the need to say to me "Where's the proof?" (as if you'd say that to someone following a strict diet because of religious beliefs?).
I used to get flustered and launch into a great rant about how carbs break into sugars and blah blah. These days I shrug, smile and reply, "You've got eyes?" And then, generally, find somewhere else to be.