Healthy Weight Loss and Your Ideal Weight

One of the first things a person thinks about after deciding that they want to lose weight is how much they want to lose, or what their goal weight should be, and many people don't know how to calculate that properly.

Personally, I just guessed.  I asked my doctor what a healthy weight range for my height would be (between 125 and 155 lbs) and then just kind of picked an arbitrary number somewhere in the middle (140 lbs).  My original method could work, but everyone is unique, even if you're the same height as someone else.  Where another woman my height could easily maintain a healthy weight of 125 lbs, I think I would look sick if I lost that much weight.  So how do we figure out what our ideal weight is?

Well, I've discovered a website: BuiltLean.com.  Marc Perry has some great articles on his website that you can access even if you don't subscribe to his program.  I found one on how to calculate your ideal weight. (source article)


So Marc Perry has a formula for calculating your ideal weight:

Lean Body Mass / (1 - your desired Body Fat Percentage in decimal form)

The formula in a simplified form looks like this:

LBM / (1 - your desired BF%)

Okay, I know what you're thinking.  What the hell is Lean Body Mass?!  Lean Body Mass is everything in your body (muscle, organs, bones, tissue, blood vessels, etc) except fat.

But how do you figure out that number?  Here's how:

LBM = Your Current Body Weight - (Your Current Body Weight x Your Current Body Fat Percentage)

I know, I know, so many numbers!  And how do you know what your body fat percentage is?  Here's another number you need to know and keep track of.  

You can figure out your body fat percentage a couple different ways.  You can buy a scale that measures certain statistics about your body including your body fat percentage, your muscle mass, your bone mass, etc.  These scales can range in price from just under $100 to over $400.  I'm looking to purchase one that's about $220 after researching and reading tons of reviews.  Another way you can measure your BF% is by using a caliper which is much cheaper to buy, although it can be difficult to use if your body fat is over a certain range.  Currently, my BF% is higher than the range ideal for using a body fat caliper which is why I'm looking to buy a scale.

Anyway, back to the formulas!  I have a number for my BF% because of my brief stint on Herbalife.  The coach I spoke with had a fancy scale like the one I'm looking to buy and so I got a baseline for my stats.  I want to give you an example so you can see how it all works with real numbers.  I'll use my numbers.

First let's calculate my lean body mass.  Remember, LBM = CW - (CW x CBF%)

My current weight is 176 lbs.  The last time it was measured on the fancy scale with Herbalife, my BF% was 41.5%.  We have to convert that percentage to a decimal, so my formula will look like this:

176 - (176 x 0.415) = 102.96 = LBM

So my lean body mass is ~103 lbs.  Now to calculate my ideal body weight.  Remember, Ideal Body Weight = LBM / (1 - your desired BF%). (For more information on your ideal body fat percentage, visit this link or this link.)

My Ideal Body Weight = 102.96 / (1 - 0.225) = 132.85

My ideal body weight is somewhere between 132 and 133 lbs.  Because I know this is going to be a difficult goal to reach, my goal weight range is between 130 and 135 lbs.  I'm giving myself some leeway. What's interesting is that I was ~130 lbs all through high school, and when I first got myself into shape in college, I weighed 135 lbs.  It's nice to know that this weight range is realistic for me.