Good question... I dunno what is the answer to your question. I'll do some Googling and get back to you if I discover an decent answer. You should email the people at Nutrisystem as they probably can answer it..
I was surprised by the low number that was suggested for my height - 156. I was certain I would never weigh that much. Now I weigh 160 and couldn't feel any better if I tried. While it might be nice to add some muscle it's also much easier to run at this weight than if I were even 5 pounds heavier so that might not be my motivation for a while. It worked for me...
BMI was developed for "average" frame, "average" muscle build and "average" activity level..
In other words, it does not apply to.
I even find the "average" to be messed up. Most guys meeting BMI are what I'd consider under-developed..
That being said, I do think we sometimes fool ourselves and could stand to lose more than we think we should. After getting to my goal of 200, yeah, I'm good, but really think I could take it under 190 and still keep some muscle. 165, like BMI recommends? That's nuts!.
As has been said many-many times around here - go for %body fat, if you can find a way to measure it..
Otherwise, just keep losing until your fat goes away! How's that for a simple answer?.
Gordo is right on..
When you get close, you can tell how fat you are. (I am not close enough yet, btw.) If you have to adjust goal up or down, it is no big deal. It is pretty easy to look in the mirror, naked and see if you are fat or cut. Also, you can take a photo, even post it here for feedback if needed. I can tell just from waist size. I need to get back to 30" to be trim again for my frame..
And if you really care (which you should), you will get someone to measure your bf% for you. Calipers are pretty good, especially if you do repeated measurements with someone who is good at it. Height-weight tables and impedance measurements are crap. But the USN logarithmic equation from neck, waist, height, weight is surprisingly good. (It is superior to a height weight chart, since neck is a good proxy of musculature and waist of fat.).
I'm kind of lecturing myself, since I worry that my goal is too high or too low. But I'm lifting to try to maintain muscle and dieting to shed fat. When I get into the 160s, I will be able to tell reality and the chips will fall where they do. And it won't shame me a bit to revise my goal up to 165 if I somehow developed muscles in my 40s. Or down to 155 if the converse. I have found that some of what I thought was muscle was really fat...and that my true musculatare is more long and ropy underneath (for instance on arms)..
Also, I can tell from the exercise weights if I am maintaining or gaining strength. For me, I am gaining strength on every muscle except for calves..
Even on calves I'm gaining functional strength, since I lift more machine weight. Just less overall weight, when BW drop is considered. And I really don't think any of us fatties need to worry about tiny calves!..
I'm 5'10' also. 174 would put you at a BMI of 25 and would be considered healthy. I never made it down that far but have been hanging around 180-182 for over 2 years now. That's been good enough for me but I may eventually get motivated to lose another few pounds just to see what it feels like...