OK i just put all my measurments in to www.mybodycomp.com and it says i have 116 pounds of lean body mass. and it also says women should have 23% body fat.

OK so I did some math and if i get to my goal wieght of 140 with 116 pounds of lean massthat sould give me 16% fat. which is to low for women.

but if i get to 150 pounds with 116 pounds of lean mass i will be right about at the 23% fat that they say women should have.

OK here is my querstion should I adjust my goal wight is 140 unrealistic?
I am 5'10 and i ahve tiny bones ( i ware a size 4 1/2 ring and can fit my thumb and pink around my wrist.)

what do you guys think?

If you can get down to that range with a lean mass of 116, then yes, you would probably find 150 a more realistic goal. However, you will lose some lean mass along the way -- even though LC diets are more sparing of muscle mass than traditional low-fat/low-cal diets, some muscle loss is unavoidable. Based on my starting measurements alone, I've lost about 7 lbs of LBM, and I wasn't happy at my original goal of 140 even though it was a reasonable BF% based on my starting stats. However, I'm still left with a lot more muscle than most women my height, and I find I'm a much smaller size than I was the last time I weighed the same amount.

Why not set a goal of 150 and see how you feel when you get there?

I'm 5'8", medium build, and am shooting for 155 right now. Then I will assess the situation. At 167, I wear a size 10 (was size 18 at 215) and look pretty good. Just have some extra fat to lose around my middle and hips/thighs. Much lower than 150 and I think I'd start to look sick.

You can't really compare yourself to anyone else. Everyone is built differently.

I personally think setting a reasonable goal is best for staying motivated. You can always lower it later.
Good luck to you!

Well, keep in mind non-fat mass is different from lean mass. The part of you that isn't made up of fat ALSO includes things like bones, muscle, and even water.

For every bit of stored fat your body contains, it also hangs on to some water with it. So it is to be expected, unless you begin to work out, that your non-fat mass will decrease as you lose more weight.

This is why it isn't realistic for someone who is still pretty far from their goal to crunch final numbers like that.

I can't give a scientific answer, but I can share my experience.

About three years ago, I lost about 25 lbs with Atkins. I got down to 145lbs, and I'm 5'8''. I went off the wagon, but got back on last Feb, and this time I'm doing Curves (resistance training). I now wear that same size as when I was 145, but I'm 10lbs heavier, and my BF % is about 7% lower.

23% body fat is a VERY general #. It is also determined by age and height.

I say wiat and see what happens when you are at 150, and go from there if you are not satisfied.