Why fad diets don't work [news]
But there is a catch: fad diets do work. Sort of. Most of them stick to a basic formula that goes like this: the diet severely restricts your daily kilojoule intake but provides enough glucose to keep your most vital organ functioning: your brain.
Your body responds by tucking into stored energy reserves (enter FAT) to keep itself going.
But, in a masterstroke of evolutionary genius, because our muscles largely determine how much energy we need, our body also chews into our muscles to supplement the shortfall.