[missmyhotbod]

I don't know who wrote that book, and where they got their info, but everyone is different. Everyone has a different metabolism, weight, height, etc. It isn't a one size fits all sort of thing when it comes to calories. A very general rule of thumb is, take your weight, and multiply by 10. that is the number of calories your body needs to maintain its current weight. As you lose weight, that number goes down. So, the number of calories you burn during exercise would be your deficit. Of course, if you are eating less than that in the first place, then you subtract your exercise from the real number of calories you are eating, and then subtract that final number from the original number to get your deficit. A deficit of 500 cals a day leads to a 1lb per week weight loss... 1000 cals a day leads to 2lbs a week.... For example... if you weigh 220 lbs, then it takes your body approx 2200 cals to maintain your weight. Of course that is assuming you are lightly active every day. I you are a couch potato, then that number is probably more like 2000 or so. That being said, if I was making the decision for myself, and I weighed 220 lbs, I wouldn't eat any less than 1400 cals a day. (I'm using 2000 instead of 2200, and that includes a workout every day that is burning 400 cals) It is said that in the long term, a deficit over 1000 cals a day will lead to your body going into starvation mode, and you will sooner or later stop losing weight. Then it will be much harder to even maintain your weight, because if you do start eating more than that severe restriction, you will begin to gain because you have reset your metabolism to be crazy efficient on a very small amount of energy. Doctors that put their morbidly obese patients on a very restricted calorie diet do so to jump start their patient's weightloss and give them inspiration and motivation to continue. Plus, of course as you lose weight, your energy increases, so they are insuring that the patient does in fact lose some weight and maybe develop the confidence to continue before they have a chance to just give up. It's never meant to be a long term situation. It can't be. Nobody could ever maintain that kind of calorie deficit for the rest of their life. Not without shrinking the stomach through surgery, and truth be told... a lot of people that have that surgery begin to stretch out their newly formed stomach by gradually eating more and more, and some of them eventually gain much of their weight back. I couldn't say exactly what a safe time frame for that type of diet would be. I can only speculate, but my guess would be no more than 3 months or so before it has an effect on your metabolism. I could be wrong. Maybe it's less than that, maybe a little more.

Sorry if you already knew this stuff... I just thought I'd contribute my 2 cents worth : D