Musings on What My Target Body Weight Should Be

One of the trickiest things to decide, I think, is what should my target weight be?  How should I calculate it? Should I go off the BMI guidelines? Or body fat %?  To make it the most difficult, I was thinking about this when they I was near my heaviest and most out of shape, with vague recollections of what I weighted in high school, or when I met my husband, or when I came back from Europe having eaten very little for 6 months.

I am going to use this forum to go through my thought processes, and would love to hear any thoughts you might have on the subject.  This might end up a pretty long post, but we shall see.

What are the alternatives?  I have two that I am using (I know these are rough, but bear with me):

• BMI or Body Mass Index
  [body weight in pounds / (height in inches * height in inches)] * 703
  example: my current BMI is [186.2 / (64 * 64)] * 703 = 32.0
• Body Fat Percentage
  I use an Ozeri bioimpedence scale, which captures body weight, body fat%, water%, muscle% and bone. I generally use a trailing 7-day average for body fat% (=T7D BF%) to smooth out volatility, and it seems to work pretty well. I calculate my approximate current pounds of fat (yuck) as my T7DBF% * current weight and then my lean mass as my current weight less my current pounds of fat.
  example: my current body fat in pounds is 41.3% * 186.2 = 77.0 pounds and my current lean body mass is 186.2 – 77.0 = 109.2 pounds

I have seen some guidelines for what range I need to be in, for each of these metrics.

For BMI:

• Underweight = less than 18.5
• Normal weight = 18.5 to 24.9
• Overweight = 25.0 to 29.9
• Obese = 30.0 or higher

For body fat %:

• Athletes: 14% to 20% (women) and 6% to 13% (men)
• Fitness: 21% to 24% (women) and 14% to 17% (men)
• Average: 25% t0 31% (women) and 18% to 24% (men)
• Obese: 32% or more (women) and 25% or more (men)

I know it is a rough calculation, but I took my lean mass (109 pounds) and added 31% to it to get a target weight that would put me in th Average category for body fat %. That gives me a goal weight of 143 pounds.  At 143 pounds, I would have a BMI of 24.5, which is just inside the “normal” level for BMI.  A “Fitness” body fat % goal of 24% would mean a target weight of 135 pounds.  An “Athletes” body fat goal of 20% would mean a target weight of 131. Ah ha ha! Who am I kidding.   

Interesting observation: when I started this journey, I was 203.4 pounds with a 48.8% body fat percentage and a BMI of 34.9.  My lean body mass was 104.1 pounds (I have lost 22.3 pounds of fat and gained 5.1 pounds of lean body mass – woo hoo).  For a body fat % of 31% – again, in the Average category – would have given me a target weight of 136 pounds, with a resulting BMI of 23.3.  

Let me get this straight – if I work out and increase my LEAN body mass, I don’t have to lose as much weight (my target weight when I started would have been 136 pounds, but now I only have to get to 143 to be in the same body fat range)?  And since I would be putting on muscle, which actually helps me to burn more fat, that would really move this whole process along?  Yep. This is me going to get my running shoes on.

I know I may get some comments on the fact that the math is a little simplified, but I have a LOT to lose here, so details are not my main concern.  I also want to help others who may be trying to figure this out for themselves.