Rather than randomly setting a goal weight, I’ve decided to use some science to find my ideal body weight. Image courtesy of FreeDigitalPhoto.net and Mister GC.

When I tried losing weight before I always picked a random number and tried shooting for it. Of course that never worked. First of all I was too focused the number on the scale, not health. Second, I didn’t consider if I was losing only fat. The last thing you want to do is lose muscle.

In my efforts to kick cancer’s ass and regain my metabolic health, I’m recalibrating my diet. To do that I’m starting to focus on maximum fitness and a reference weight, (AKA, my ideal body weight).

BMI vs. Reference Weight
Thankfully the Body Mass Index (BMI) is being exposed for the bad science that it is when it comes to defining healthy weight.

BMI is the preferred method of the US government to determine those obesity numbers the news media loves to report. All BMI does is measure the relationship between your height and weight. But nothing relating to muscle mass, bone or body fat.

It’s not a very good measure of health and fitness to say the least.

Reference weight is a way of looking at the individual, factoring in lean muscle mass and desired body fat levels, something BMI doesn’t do.

Ideal Body Weight Formula
There are many sites out there that offer free calculators to determine your ideal body weight, but many are based off of BMI. I found a site that provides a formula to calculate your reference weight. While I’m sure it isn’t the only one out there, it offers me a good start.

To calculate my ideal body weight, I’ll use the following formula:

Lean Body Mass/(1- Desired Body Fat Percentage)

Lean Body Mass (LBM) is your body weight (muscle, blood, bones and organs) without the fat, or:

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

OK, so how do you calculate your percent of body fat? That’s a can of worms! There are a lot of different ways and some are more financially painful than others. Thankfully Nerd Fitness has a list of the 7 ways you can calculate body fat.

I’m using the number (29%) provided by Gold’s Gym when I did last year’s fitness challenge. It is also consistent with Nerd Fitness’ “Take A Look” technique.

My LBM equals:

185 – (185 x 29%) = 131.35

Right now, without my fat, I weight 131.35 pounds.

To calculate my reference weight I picked 21% body fat, putting me in “fitness” range (21-24%). Going from 29% body fat to 21% body fat may seem like a stretch. But considering the changes I’m making to my workout routine once my doctor clears me I think 21% body fat is very doable.

My Reference Weight equals:

131.35/(1-21%) = 166

My ideal weight is 166 pounds. In most cases, that means I’m carrying around only 19 pounds of excess fat. However, I also have a lot of sagging skin from losing 145 pounds. I have no way to measure how much weight in extra skin I’m carrying around. Since skin is an organ, it is counted in my LBM not my body fat. So that excess skin does skew my 131 pounds of lean body mass. But until the time comes for surgery, I need to focus losing 19 pounds of fat and building strength.

What’s The Point Of This Little Exercise?
Now that I have an ideal weight can start changing up my diet and fitness routine. My goal is to maximize my health and give me any edge over cancer. Having a somewhat scientific method for determining ideal weight is much better than shooting for a target that your body can’t get to.

But let’s be clear: my reference weight is a milestone in my journey. The ultimate goal is repairing my metabolic system. That’s what will help me kick cancer to the curb.