Body Fat help

doelani

I am a bit confused about the body fat figure.

My starting details where

Weight 279lb
Fat 44.5%
Water 40.5%
BMI 47.7%

Now after 5 weeks

Weight 260lb
Fat 43.6%
Water 41.1%
BMI 45%

I have lost 19lb and 2.7% off my BMI but only 0.9% body fat???? am I doing somehting wrong?

thanks Doreen

SHBoss1673

well, first I'll ask how you are measuring your body fat %? If it's via a scale, they're really not that accurate. Second, don't worry about body fat % right now, it's something you want to concern yourself with when you start getting close to your goal weight. I mean, it's great that you're paying attention to it, but body fat scales use bio-electrical impedance for fat measurement. And that is a process that calculates how fast electrical impulses travel through your body. The problem with that is hydration levels play a huge role in how fast those impulses travel, so in order to have accurate results all your water levels must be basically identical. This is pretty much impossible in normal life, so accuracy can be up to 20% off in those scales.

While I'm ALL about body fat %, trying to track it monthly is probably not the best way to measure progress. For now, I'd go more on your measurements and weight. If they continue to go down then you're heading in the right direction. Once you start getting down to within 25 or 30 lbs of goal, then I would recommend a BF% test done at a lab (they cost between 50 and 100 bucks usually), and then done once every 3 or 4 months until you reach goal.

That's my thoughts on the subject anyway.

best luck to you, and congrats on the excellent loss.

NavySailor

You are really not providing enough information to make a determination if what you are doing is right or wrong. You have lost 19lbs and almost 1% of BF...that really is extraordinary.

skyski_tige

I dropped 20 pounds and the body fat % barely moved! At 51 pounds down it still only went down about 4%.

You are doing great! You will see the inches go off with the weight and be very proud of what you have done!

doelani

thanks for replies everyone

I am mesuring the body fat on my scales. have only done it at start of diet and then today, was just curious really.

I did not measure myself when I started just going by weight so do not really know how many inches I ahve lost. I suppose I should have but more interested in the weight coming off lol I can see a difference in my clothes so know I have lost without even going onto scales

ProTFitness

If your using a scale to measure your body fat it is probably off. They are 30%-50% the best way is hydrostatic(aka the dunk tank or Skin fold callipers) those are the top 2 and most accurate.

SHBoss1673

If your using a scale to measure your body fat it is probably off. They are 30%-50% the best way is hydrostatic(aka the dunk tank or Skin fold callipers) those are the top 2 and most accurate.

Bod Pod is the same accuracy as the hydrostatic test, better than calipers (skin fold), and doesn't require you to be dunked in water.

you can google bod pod and get the locations near you. Plus they are way cheaper, the one near my house is 35 bucks. And with a 1.5% margin for error, short of DEXA or MRI it's the most accurate way to do it. Calipers are about 5% margin for error with a really experienced person doing it (if they aren't they can be really badly inaccurate).

TrainingWithTonya

While a BIA Scale isn't the most accurate way to determine body fat, it is better then nothing and since you already have it you don't have to spend money to do the more accurate stuff. Comparing BIA to Bod Pod for example, will be comparing apples and oranges, so I'd say to just keep using what you have. From what I've learned in my Exercise Physiology program, the BIA scales have a 4% +/- range of accuracy so they aren't bad, but changes of less then 4% can be thrown out as just accuracy issues. For example, water content of the body will throw off any BIA (even the expensive ones in our lab at school), so if you don't have the same % of body water on it, then you can't compare the BF% numbers either. Trying to keep the water % numbers up will help you get your water in though, so it is a great tool for that. LOL

As for BMI, that is simply a ratio of height to weight (technically it is weight in kilograms divided by height in meters squared) and not a percentage of fat or anything else in the body, so if you lose weight and don't shrink in height, then your BMI will go down regardless of what you lost. If you lose mostly muscle or water, then you will see a big change in the BMI but not in Body Fat %. It takes a long time to burn a pound of fat, though, because it takes burning 3500 calories while using fat as the primary substrate for fuel to lose one pound of fat. It's a very complex system where carbs are burned first, then fat, and then protein, but it is also dependent on intensity and duration as well as intake, as to what is being burned, so its not as simple as just cutting 3500 calories to lose a pound. A pound of muscle is only 600 calories so if you aren't eating the right foods for your body to want to pull from fat stores, then you will use protein to make energy and will actually lose muscle instead of fat. And when you are burning carbs, you lose the water that is stored with glycogen in the muscles as you burn it so you that can affect it too. So like was said earlier, you don't need to check your body fat % very often because it will just be discouraging because it seems to take a lot longer to burn because you are actually burning a little of each substrate while doing most average exercise programs.

TrainingWithTonya

If your using a scale to measure your body fat it is probably off. They are 30%-50% the best way is hydrostatic(aka the dunk tank or Skin fold callipers) those are the top 2 and most accurate.

Bod Pod is the same accuracy as the hydrostatic test, better than calipers (skin fold), and doesn't require you to be dunked in water.

you can google bod pod and get the locations near you. Plus they are way cheaper, the one near my house is 35 bucks. And with a 1.5% margin for error, short of DEXA or MRI it's the most accurate way to do it. Calipers are about 5% margin for error with a really experienced person doing it (if they aren't they can be really badly inaccurate).

I love our Bod Pod at school! But we don't allow anyone to use it who isn't in the Exercise Physiology program or participating in one of our research studies. The school says its a liability issue even with a professor running the test. Where I am in South Georgia, it's the only one I know of. All the gyms around here use BIA or calipers. So, to the OP, while the Bod Pod is the best, unfortunately, not everyone has access to one. So don't be surprised if you can't find one in your area that you can be tested with.

nehptune

the numbers don't really make sense unless you calculate how much body fat you had before, how much you have now, and then you can work out how much fat you have lost.

so, before you had:
279 x (44.5/100) = 124.15lbs of body fat

now you have:
260 x (43.6/100) = 113.36lbs of body fat

that means that you have lost 124.15 - 113.36 = 10.79 lbs of fat
that's pretty good going i think!

also, even if the scales are not the most accurate way of measuring your body fat, they are pretty consistent (if you try to always weigh yourself under the same conditions) so a good way of tracking changes in body fat even if the number isn't 100% accurate.
another thing to bear in mind is that using callipers can be incredibly inaccurate if the measurement is done by someone inexperienced using them, and can be much less consistent if you aren't careful to always measure the same sites on the body in the same way.

these sites have some more info on measuring body fat:
http://www.new-fitness.com/body_fat_analyzing.html
http://www.medicinenet.com/script/main/art.asp?articlekey=56830

SHBoss1673

the numbers don't really make sense unless you calculate how much body fat you had before, how much you have now, and then you can work out how much fat you have lost.

so, before you had:
279 x (44.5/100) = 124.15lbs of body fat

now you have:
260 x (43.6/100) = 113.36lbs of body fat

that means that you have lost 124.15 - 113.36 = 10.79 lbs of fat
that's pretty good going i think!

also, even if the scales are not the most accurate way of measuring your body fat, they are pretty consistent (if you try to always weigh yourself under the same conditions) so a good way of tracking changes in body fat even if the number isn't 100% accurate.
another thing to bear in mind is that using callipers can be incredibly inaccurate if the measurement is done by someone inexperienced using them, and can be much less consistent if you aren't careful to always measure the same sites on the body in the same way.

these sites have some more info on measuring body fat:
http://www.new-fitness.com/body_fat_analyzing.html
http://www.medicinenet.com/script/main/art.asp?articlekey=56830

I disagree that scales are accurate with regards to deltas, it's all dependent on hydration levels, if your hydration is different, the % change can be off. I did a test at the gym where they used one of the professional quality tanita scales about a year ago. I took (they had it calibrated about 2 weeks prior to the testing) my BF% every day for 5 days and had 5 different numbers, one day (in the middle) I was at 15%, which is crazy since my last bod pod was 10.15%, the other days ranged from 9% to 13% give or take (I forget the numbers). Needless to say, most people won't see measurable changes in BF% in 1 week, regardless, that test really does show about the level of accuracy, that's a 50% margin for error, that's not good. And this was with one of the professional scales, not even the (admittedly) less accurate home scales.