Why exactly does chronic low calorie eating result in slowed down metabolism. That doesn't seem to make much sense to me. It would seem like if one consistently ate fewer calories than their body needs, they would consistently lose weight.

Well, if you look at a lot of people (women in particular) who have eaten rediculously low calories for a long time (800 cals a day perhaps), they generally stop losing weight and wonder why. Up there calories to a more realistic number, the weight loss starts again.

I'm not going to say that the whole 'starvation mode' idea is totally correct, but the bodt will definitely do a number of things with consistent super low calorie eating.

1. Slow metabolism so that you are using less energy (calories) to function
2. Slow YOU down, make you more tired, lethargic, less interested in moving around, as a way of preserving energy.
3. Do all sorts of funky hormonal stuff to make you want to eat.

Of course, chronic calorie restriction, a la real starvation, will eventually make your body start to devour it's own lean tissue to use as a source of energy, but very low calorie diets will do that too, not cool at all, considering muscle is the most metabolically active tissue in the body.

Lose muscle, metabolic rate is slowed anyway, so chronic low cal diets are really a self perpetuating cycle of doom.

From what I understand when you start out fasting you should start slow and work your way up. A day here, a while later maybe two days and at some point you can work your way up to fasting for a week once or twice a year. Is that wrong?