What does it tell you about why?

That all looks very weaksauce.

If EY really has an unusual metabolism, it seems to me he (rationally) should be willing to spend considerable time and effort to figure it out.

Ideally, he should go into some university's metabolic ward and spend a week or two there while his personal biochemistry and the way it reacts to stimuli is being carefully looked at.

While that may not be very practical, going Tim Ferriss is considerably easier: get a lot of tests done and keep on repeating them, keep a food diary, keep a log of parameters of interest (sleep, energy, mood, etc.), get a blood glucose meter, get keto strips, run controlled experiments on yourself, etc.

If one does have an unusual metabolism, statistical expectations based on normal people don't apply. That's a big issue.