right guys i'm confused
some people seem to be sying that you should eat 12 x current weight in calories and others are saying 12 x target weight. who's right?

I've always heard 12 times your current weight...

current weight

Can someone explain where the 10x-12x came from? The only thing I see on atkinscenter.com is this:

"If you are used to counting calories and it makes you uneasy to not do so, know that women usually can safely consume 1,800 calories a day and still lose weight; men can typically take in 2,000 calories, and in some cases more."

Where did the 10x-12x originate?

Click here for a good discussion about the 10x rule.

It is a nice discussion on the 10x-12x rule but I don't see anyone backing up their claims or indicating where that number came from (i.e. a book, website, scientific research paper, etc.).

Also, there is one important piece of information in that discussion that to me seems to be an incredibly import caveat to the 10-12x rule that I rarely see discussed.

wbahn writes:
"Now, about that 10x rule. That is a rule of thumb that is applicable to people not too far above their ideal weight - and you probably are close enough. For people way above their ideal weight, the rule of thumb is along the lines of 400 calories plus 10 calories for every pound of lean body mass plus maybe one or two more for every pound of body fat."

Again, there is no reference to where basis for that assertion came from but if it is true, we shouldn't be throwing 10-12x number around willy nilly and telling people who are 350lbs to eat 3500-4000 calories per day.

wbahn also wrote "you need to support close to your BMR". If that is the case it would make sense to set your daily calorie limit somewhere around your BMR which would theoretically be a better number than just 10-12x your current weight.

There seems to be a conflict between what Atkins says (1800 for women, 2000 for men) and the 10-12x rule. What I really want to know is where that 10-12x rule came from. I am not trying to say the 10-12x rule is wrong, I just want to know who came up with that guideline.

I want to second what wbahn had to say. There is no way that most of us with a lot of weight to lose could eat a minimum of 10x to 12x our body weight in calories and lose weight. For me, that would mean eating 3,000 to 3,600 calories a day. Even on a lowcarb diet, and even with the hour of exercise I get each day, I cannot lose weight on 3,000 to 3,600 calories a day and it is absurd to think I could. Also, if I tried to eat that much each day I would have a chronic stomachache -- how can that be healthy? I have no interest in stuffing myself until I burst.

I don't count calories, but the few times I have figured my daily caloric intake it has been closer to about 1,800 calories a day. I have lost almost 70 pounds in a little over seven months eating this way. I am not hungry and I continue to lose steadily.

Please be careful when providing advice to people to note that the 10x to 12x rule does not apply go to people with a lot to lose. As to whether or not it applies to people with a little to lose, I don't know. I simply folllow Atkins' advice -- eat at least every six hours when awake, eat until you are full but not stuffed, eat your vegetables, eat plenty of fat, and count carbs. As long as someone eats something with some protein and fat at least every six hours, starvation mode should not be a problem.

The 10-12X body weight as a guideline is just that...a guideline. No one guideline will fit everyone and as Bill pointed out, it may not be appropriate for those who are extrememly overweight. The purpose of the guideline is to make sure that you get enough calories to support your basal metabolic rate (BMR) and avoid stressing your body through a caloric intake that is too low and is usually presented to people who appear to be eating well below what they should in calories. Remember, a stressed body will not easily let go of excess fat and cutting your calories too low is counterproductive to weight loss as your metabolism will shift downward to compensate for the low caloric intake. Obviously, nobody can make you eat more than you are comfortable with, but if weight loss stops or is very slow, caloric intake is one of many things to take a look at.
Having said that, here is a link to a page that explains how BMR is calculated. Please note that the basic calculation is 10x current weight, so that number isn't just a guess or unscientific.
http://instruct1.cit.cornell.edu/courses/ns421/BMR.html

You can also use Fitday at www.fitday.com to get a good idea of what your BMR is and base your daily caloric intake on that.