Hola Aniki!!

Restricting himself like that is very unhealthy. Has anyone brought this to his attention of course only out of concern?  Some people go from one extreme to the other I hope he finds a happy & healthy balance before he has another dizzy spell and has to be admitted.

"Fad diets"

If you don't change your lifestyle to something reasonable and stick to it, then your body grows accustomed to the "fad diet." The SECOND you quit it, you gain the weight back really quickly.

That's scary, has he seen a doctor, sounds like there might be more going on than just extreme weight loss.

My boss is on the coffee, nicotine and jolly rancher diet. He drinks nothing but coffee, smokes like a chimney and sucks on jolly ranchers all day...and he never feels good. Gee I have no clue why?

One of his co-horts tries very hard to mimic his diet and mostly succeeds, but has succumbed to eating goldfish out of a huge box in their office.

They are both very skinny and yet they are always sick and complaining about body aches and pains. The one who succumbed to the goldfish as a pay off always walks by my desk and looks at my lunches or snacks and goes "god that looks so good, I could never make stuff like that."...yeah because a salad with tomatoes, avacado and chicken is so outside the scope of a novice chef...eye roll!