Why Fat Matters & Weight Doesn’t

I’m careful in my use of the terms :”fat loss” and “weight loss.”  In my last post about diets, I discussed weight loss, but I would like to be clear about why it’s important to know the difference.

“Weight Loss” means the number on the scale got lower.  It doesn’t mean anything else.  It doesn’t mean my pant size went down or that my waist got smaller or that my body composition changed.  If I started at 33% body fat and lost 10 lbs, I might still be at 33% body fat, just a little lighter and probably a little smaller.  But I’m just as fat as I was at the start, and now I have less lean mass too.  Here’s a great blog post with pictures that demonstrates the difference body fat makes in the same person, both pictures taken at the same weight:  http://tinyurl.com/scaleaddict

“Fat Loss” is exactly that: losing body fat.  It can be measured by calipers, BodPod, DEXA or those bio-impedance devices with little metal plates that you hold in your hands or stand on with bare feet (my Tanita scale has one).  Most of us don’t have a handy-dandy body fat measuring device.  What we have is the mirror.  The mirror tells you the best story – you can see if you’re getting leaner or not.  Take your measurements and follow them: getting leaner usually includes getting smaller. 

If you want to look good naked, then you shouldn’t care about your weight.  You should care about your body fat.

If you want to look lean and fit, you shouldn’t care about weight loss.  You should care about fat loss (and, probably, fitness too.)

Here is the problem with thinking in terms of weight loss alone.  When your scale weight goes down, it is often composed of more than just fat.   Some of it may be water.  More importantly, some of what is lost may be lean mass.  Lean mass is everything that isn’t fat.  It’s the good stuff you want to keep.  It includes your bones (which you want to be dense, and therefore heavy), your organs and ligaments (which you want to be strong, healthy and well-hydrated), and your muscles.  You want to keep every ounce of muscle you can.

It’s a well known fact that your muscle mass affects your metabolism.  More muscle will speed up your metabolism, even if only by a few calories a day. You can’t afford to lose any!

When we lose weight, we lose both fat and lean mass.  My goal, as I expect yours would be too, is to lose fat while retaining as much lean mass as possible.  I don’t want to get lazy and start celebrating “weight loss,” because it may or may not actually be a step in the right direction. 

With all that said, it’s hard not to celebrate a loss on the scale.  We’re programmed to want to a lower number.  It makes us happy to see it get lower and lower.  There’s nothing wrong with being a little happy to see the scale go down five pounds, as long as we remember that the scale number won’t guarantee that we’ve gotten any closer to our true goal of looking sexy with our clothes off!