What Are The Dangers Of Losing Weight Too Quickly?

[Barsel]

A friend of mine decided to lose some weight and he is doing this by hardly eating anything. He is 71yrs old and about 6ft tall and he is going by the weight charts that tell you how much you should weigh for your height.He reckons he still has another stone to lose, but he is looking really gaunt and to me, his skin looks yellow. Is he putting his health at risk? Thanks.

[Cloverjo]

Eating almost nothing might lose the weight, but it makes it highly likely he will put it all back on again. I've done it myself, and have seen a couple of OH's relatives starve down to 7 stone, only to balloon back up in no time.
Encourage him to eat healthily, and not to starve.