4. Body Fat Percentage is More Important Than Weight Loss

By | February 12, 2004

Do not live and die by your body fat percentage. Body fat is, like the scale, another way to gauge progress. But when you are extremely overweight, body fat measurements can be extremely prone to error.

It seems like every male over 250 pounds is automatically 30% body fat regardless of his height or weight or size.
The fact of the matter is that many body fat measurements were not calibrated to extremely overweight people.

The problem with worshiping a body fat measurement is that it can set unrealistic expectations.

I remember when I first computed my body fat. I quickly calculated what my lean mass was and then did the math of what I would weigh at 8% body fat if I did not lose any muscle mass. Then I started dropping pounds and eagerly waited for the day I would see my ripped six-pack. Of course, that day came and went — but no six-pack! I was frustrated, and like many people at this point, made up the excuse, “My genetics must be keeping me from it”. The reality was that my “measurement” was off by a long shot, and I put too much weight in that one measurement.

If you are curious and want to track your progress, use a combination of measurements. Sure, body fat is a valid one to use because you do want that measurement to go down. But don’t place too much emphasis on its being the exact, correct measurement. Being able to state that you lost exactly 10.5 pounds of fat and gained 2.5 pounds of lean mass in a given time frame might be great for supplement ads or to promote the latest weight loss fad, but numbers that precise aren’t realistic without expensive, laboratory-grade equipment, or at least a very skilled professional.

Instead, use body fat, along with the tape measure and your scale weight, to track trends. Don’t worry about trying to figure out what you will weigh at a particular level of body fat, because every person is different. It is hard to predict just how much lean mass you will gain or lose. I have seen so many people, who do not even realize what lean mass is, frustrated by loss of lean mass due to body fat calculations.

Lean mass is not only muscle — it includes most of the nonfat substances in your body. Even fat itself contains water, so when you lose a significant amount of fat, you lose a significant amount of water. This will register as a loss of lean mass, but that does not mean you lost muscle!

It is amusing sometimes to see people who are far from seeing their six-pack claim they are 8% body fat while some who are ripped to shreds swear they are 18% body fat. This is an example where the number becomes too much of the focus.

Really, who cares except you? You are the key person — if you feel great and like the way you look, does that exact number really matter? Remember, we are not talking about a bodybuilding competition here!

If you are really interested in giving yourself a reality check, consider the fat free mass index.

The equation is your weight (in kilograms) divided by your height (in meters) squared.

A study of elite athlete (some admitted steroid users and some not) combined with an analysis of 20 Mr. America contest winners from the 1939-1959 pre-steroid era, determined that a fat free mass index of 25 is pretty much an upper limit for someone who does not use steroids.(3) A fat free mass of 19 is the average for males.(4)

To calculate your lean mass (click here to use the calculator):

First, subtract your estimate for body fat from 100 to get the lean mass amount.

For example, if you believe your body fat percentage is 30%, then your lean mass percentage is going to be 70% (100% – 30%).

Second, divide the result (e.g.,79% by 100 to get a decimal. In this case, the result is 0.7.

Third, take your weight and divide by 2.2 to convert it into kilograms.

Fourth, multiply the number of kilograms of weight (in this case, 84) by the percentage of lean mass (0.9) to arrive at the number of kilograms of lean mass (in this case 76 kilograms).

Fifth, convert your height from feet and inches to meters by multiplying the number of feet and inches by 0.0254.

For example: I am 5 ft. 10 inches tall (70 inches). 70 inches multiplied by 0.0254 = 1.78 meters.

Sixth, multiply the number of kilograms of lean mass by your height in meters squared to get your lean mass index. In my case, that’s 76 x (1.78 x 1.78) = 23.90.

In the study, the Fat Free Mass Index was adjusted for a 1.8 meter tall person. So,

Finally, to arrive at an adjusted Fat Free Mass Index (FFMI), use the following formula:
FFMI + 6 * (height in meters – 1.8). In my case, that means, 23.90 + 6*(1.78-1.8) or 23.90 – 0.12 = 23.78 or 23.8.

To Recap:

Fat Free Mass Index (FFMI) = Lean Mass (kg) / Height (m) ^ 2
Adjusted FFMI = FFMI + 6.0 * ( Height (m) – 1.8 )

If you use this equation and find that your fat free mass index is higher than 25, then there is a good chance your calculations are off. If it is less, it does not mean it is more accurate but at least it is in a more probable range.

See also: Body Fat Calculator

If you have more than 30 pounds to lose, give yourself a break. The mirror and your clothes will show if you are losing weight, and the last thing in the world you need to trouble yourself with are these insane equations. You are fat and you now are eating better and working out. You are losing weight and achieving your goal. Who cares what your body fat measurement is? You are becoming less fat.

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2 thoughts on “4. Body Fat Percentage is More Important Than Weight Loss

  1. Belai Mariam Jesus

    I recently got myself a digital scale called whitings, a UK product that measures your weight and calculates your BMI and Lean mass and Fat mass.

    My wight is 170 lbs or 77 kg, my height is 6 feet or 72 inches and my calculated BMI is 23 and lean mass 95.5% and Fat Mass 5.5%.

    This does not sync with my other scale that gave me 24% fat. I am concerned which measure is right?

    Let me know.

    Dr BMJ

  2. Derek

    Are you sure your formula for adjusted FFMI is correct? The papers I have seen say the last factor is + 6.1 x (1.8 – height)

    Your adjustment is + 6.0 x (height – 1.8)

    The factor is supposed to adjust upward a bit for shorter people, and downward for taller people, and yours does the opposite

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