If not eating causes weight gain, why are anorexic people so skinny?

Question

I have read that skipping meals and not eating slows down your metabolism and causes weight gain. If this is true, then why are anorexic people so thin? Please note that I am NOT anorexic; I'm just wondering how this is possible scientifically. Thanks.

Answer 1

basically, if you eat too little your body goes into starvation mode, eating muscle rather than fat and slowing down your metabolism so that what little you do it is digested ultra efficiently.

Answer 2

They are so thin Because their bodys have nothing to feed her to keep her alive so it feeds on itself and causes them to loose weight, but also become so skinny they can die.

Answer 3

If you starve yourself, your body senses that it is receiving limited food resources, so it upregulates your digestive system to be much more efficient, and slows your metabolism to prevent unneccessary energy expenditure). So you get more nutrition from the food you DO eat.

If you then get more food, your body still extracts more nutrition from it - so you put more weight on than you otherwise would have. This is why binge/diet cycles don't work: your body senses the "starvation" of the diet, and you put on more weight when you binge.

Anorexics OTOH, or people who are genuinely starving, never get to the "not starving any more" bit, and they continue to lose weight because they just aren't obtaining enough nutrition.

Also, they generally don't receive enough vitamins, minerals, etc. from the limited foods they DO eat. Several vitamins are essential for your body to be able to extract nutrition from the foods you eat - so their digestive systems don't work as well as they should.