I third pro help.
could have helpful bits to finding that help.
As he is doing a lot of stuff, like reading and going running or skiing, he feels that he needs to be at his top shape all the time.
as soon as he feels a bit hungry or worried, nothing I say matters, he just starts eating.
Why burning the candle at both ends? Can't he do his time management so there is time for activiites and time for rest in a better balanced way?
Anxiety management, panic attacks, cortisol levels off. He could be confusing the anxious butterfiles in the stomach feeling with hunger feeling and doing emotional eating to stuff it down.
Thinking patterns that are OCD or hypochondria or "off" in another way -- http://www.lowselfhelpsystems.org/index.asp
to stop working himself up and / or meds to chill on the anxious -- xanax?
Blood sugar, cholesterol, and metabolic blood panel -- check for thyroid, diabetes/prediabetes, wheat allergy/sensitivity/Celiac.
High LDL and High triglycerides and non-alcholic fatty liver ---> Some people cannot deal with wheat well. Overloading on it makes them not be able to feel full or hungry right and messes with their heads with the blood sugar and downs. (This is me).
QUALITY of nutrition. If he's eating lots of crap, it's lots of crap. There no nutrition there and that could explain the fatigue.
I'm not a doc -- just possible places to look at. But he def could see a doc and get to the bottom of all this.