So I got a new scale this morning because I'm tired of trying to decide on a goal weight and want to just base it on how I feel, look, fitness level and general health. So I wanted a scale that had all the bells and whistles and calculated body fat and whatnot. Thank God it was the same as my old scale, I was terrified I was going to be posting "I got a new scale and it's 10lbs heavier than my old scale".
Anywho. My BF is 33% which is considered high. I'm not suprised, I can certainly see some areas particularly my mid section that are flubby. But I'm just wondering how high it must have been at 268lbs, I must have been over 40% maybe even 50%...I mean I was almost half fat...so sad...
So what is a realistic goal for BF? It looks like the lean to normal range is 17-25%. So I think something under 25% would be good, but how does BF relate to weight loss? I know that it's probably hard to say because you never know if the lb you lost is muscle, water or fat. But in theory if I lost 1 lbs of pure fat how many % would that be? I guess I'm asking because I have 10-20lbs to go and I am weight lifting so I'm hoping I'm losing more fat now, but is a 7-10% loss in 10-20lbs possible?
You probably don't want to hear this, but I have found the body fat % portions of scales to be highly inaccurate - they measure LOW. At least mine does as does several other ones that I've used. Mine is a Tanita, one of the best. The weight is HIGHLY accurate, but the body fat - ummm, not so much.
I remember a long time ago, when I measured mine with one of those hand held devices, gosh I don't remember the exact number, but boy was it HIGH.
You probably don't want to hear this, but I have found the body fat % portions of scales to be highly inaccurate - they measure LOW. At least mine does as does several other ones that I've used. Mine is a Tanita, one of the best. The weight is HIGHLY accurate, but the body fat - ummm, not so much.
Interestingly enough this one is in the middle if the two calculators I used. One said 37% the other 27%. I'll get a real reading done at some point but figured this would be a good gauge and at least I'd be able to see if I was making any progress.
Interestingly enough this one is in the middle if the two calculators I used. One said 37% the other 27%. I'll get a real reading done at some point but figured this would be a good gauge and at least I'd be able to see if I was making any progress.
But in theory if I lost 1 lbs of pure fat how many % would that be?
Well, setting aside the accuracy of the numbers you're starting with, it's just math.
You weigh 159.0 pounds and have 33.0% body fat. That's 52.47 pounds fat and 106.53 pounds LBW.
If you lost 1 pound of pure fat, your new numbers would be 158 total pounds, 51.47 pounds fat and the same 106.53 pounds of LBW. Your new bodyfat percentage would be 51.47/158 = 32.58%
So you'd lose about 0.42% body fat with that pound.
The next pound of pure fat lost: 50.47/157 = 32.14%. That pound would be about 0.44%.
So you can see that if you continue losing pure fat, the percent goes up a wee bit each time, since your LBW is not going down.
But of course you will lose some LBW too (LBW isn't all muscle).
Quote:
Originally Posted by ncuneo
I guess I'm asking because I have 10-20lbs to go and I am weight lifting so I'm hoping I'm losing more fat now, but is a 7-10% loss in 10-20lbs possible?
If you lost pure fat with a 10 pound loss, you'd go from 159 to 149 total pounds, and 51.47 pounds fat to 41.47 pounds fat.
New bodyfat would be 41.47/149 = 27.83%
33% - 27.83% = 5.17% decrease in bodyfat percentage.
If you lost pure fat with a 20 pound loss, you'd go from 159 to 139 total pounds, and 51.47 pounds fat to 31.47 pounds fat.
New bodyfat would be 31.47/139 = 22.64%
33% - 22.64% = 10.36% decrease in bodyfat percentage.
Having seen your pics (those that you posted last week), I doubt that your BF is 33%. That seems to be awfully HIGH for what you look like.
Although looks can be deceiving. I don't know if you did any muscle-boosting exercise during your weight loss or not. But the 33% really surprised me.
When I started, (at 208 lbs), my BF was measured as 34.4%. That was at the gym, using a similar gizmo (not calipers). When I was at my best last summer, my BF% hovered between 21 and 22%. Again, the measurement was obtained at the gym but also at a naturopathic clinic using some other device, and the two measurements were less than 1% within each other, so I assumed them to be fairly accurate. Of course, it is possible that they were BOTH wrong but that was what I had access to. I am a bit taller than you but than I did a fair amount of weight lifting so I know I was adding lean body mass as well.
I saw a chart somewhere online that listed my BF% (around 21%) as excellent for my age (I turned 50 last August). In general, between 21-24% is considered FIT and anything below 20% is considered ATHLETIC.
It's quite hard to get below 20%, unless you get really lean and do a lot of intensive training.
I found this calculator which measures neck, waist and hips for women. I like it! I also have a chart in the back of my personal trainer book you may find helpful:
Mine was 41% back in March. Now it's 36%. I'm happy with that. I'm still excited to get to poor on my chart! LOL! A little like I'll be excited to finally be overweight!
Scales that measure body fat are very unreliable. They are hugely impacted by your hydration level, among other things.
Calculation by measurements doesn't work too well, either, though I imagine it is more accurate for those without a lot of muscle definition. Still, water immersion is best, followed by calipers. These two methods are leaps and bounds above the others. Certainly, however, using measurements or a scale you already own is more cost effective. Just don't get too invested in the numbers you get, since they can be off by quite a bit.
Last edited by Petite Powerhouse; 05-17-2010 at 12:13 PM.
Holy Cow 33%BF now I wonder what I was!
LOL! A little like I'll be excited to finally be overweight! 
