What's in a number?

Do not put your faith in what statistics say until you have carefully considered what they do not say.

- William W. Watt

I could throw in some statistics about the national prevalence of obesity, the number of people on a diet at any given time, or the average age when a girl starts dieting.  But what do those numbers mean to me?  How would they help me change my life?

I know that having a higher Body Mass Index (BMI) is strongly correlated with a number of health issues, but that doesn't help me lower my BMI.  It also doesn't take into consideration the ratio of body fat to muscle mass.  Michael Jordan, in his prime, had a BMI of 27-29 and I challenge anyone to say he was overweight!  While the BMI is an easy and effective screening tool, it doesn't provide a comprehensive picture of an individual's health and doesn't indicate which changes are best for that individual.  Other measurements used in conjunction with the BMI can include the waist-hip ratio and body-frame (based on wrist or elbow).

What about clothing sizes?  There's often talk about how Marilyn Monroe was a size 12 ... and she was, by the sizing standards of the 1950s and 1960s.  Since then there's been a gradual shift in sizing.  Nowadays, Marilyn would probably be a size 6, and even that would depend on the store she was in.  Don't forget the differences between designers, brands, and stores.  Even within a store - I've tried on two pairs of pants that were the exact same style and had one fit while the other doesn't.  I'm amazed to see the variable waistbands for shorts that are all marked as "Size 4" (go see for yourself!).  I try not to get caught up in the sizing game or to attach too much meaning to a particular number, though I will confess I'm much more tempted to buy something if it's a smaller number!

If I can't rely on the clothing sizes or the BMI, what can I use as a measure of my physical status or my change in status?  (I'm not even sure if "status" is the best word to use there.)  Should I defer to the number on the scale?  After all, a pound is a pound.  But that doesn't necessarily mean ONE thing.  Two people can be the same height and weigh the exact same amount, but have drastically different body compositions and appearances.  Weight also fluctuates over the course of the day, as much as 5 pounds at times, and can be vulnerable to salt, time of last meal, liquids consumed, and menstrual cycle.

What about those scales that measure body fat percentage?  I've had trouble with those, and I'm not sure why.  Both scales that I used consistently calculated my BF% between 35% and 27%, depending on where I was with my weight loss and fitness efforts.  By comparison, the 7-point and 10-point caliper tests offered by my trainers (which are proven to be more accurate) estimated my BF% to be almost half that!  I haven't yet tried the "Bod Pod" but am tempted to see what it says.

What do I advocate?  Weighing on a regular basis to track any trends, body measurements using a tape measure (though I rarely do this myself), photographs as opposed to looking in the mirror, and the fit of the clothes I already own.  And the best way to get these numbers to change is to track those other numbers - time spent exercising, calories burned, calories consumed, and portion sizes.

Here are a few statistics about me:

• I'm 5' 5" (actually 5' 4 3/4" but I round up)
• In December 2007:
• I weighed 189
• My Body Mass Index was 31.45 (Obese Class 1)
• I wore size 14 pants
• My body fat percentage was 33%
• In September 2010
• I weighed 137.8
• My Body Mass Index was 22.8 (Normal Weight)
• I wore size 4 pants
• My body fat percentage was about 15%

What do these numbers mean?  Each one by itself, not much.  Imagine they're each a snapshot taken in time with no context.  However, take the snapshots, fill in the other pieces of information taken over time, then put them together into a "flip-book" and watch how they create a story.  As a whole, they show that I've been kicking butt with reaching my goals.  (Now, to reclaim them!)

Food Log:

• Breakfast
• 4 egg whites and 2 eggs with salsa
• Lunch
• 4oz chicken with chipotle mustard
• Green beans
• 1 tablespoon peanut butter
• Dinner
• 4oz chicken with chipotle mustard
• Green beans
• 20g almonds
• Snack
• Generous tablespoon of peanut butter

Exercise:

• Time: 60 minutes
• Level: Level 1 for 1 minute, Level 4 for 58 minutes, Level 1 for 1 minute
• Calories:  650+ (calorie burn going down as my conditioning begins to return)
• Distance:  5 miles

I came close to not exercising today, purely because of procrastination.  I was home all day long and didn't climb onto the elliptical until after 8pm.  Until then, I was puttering around the house, doing laundry, taking care of some paperwork, and doing some projects.  Even though I had my workout clothes on for half the day, I just kept putting it off.  I'm really glad I was able to overcome that inertia and get that workout in!


Today's Weigh-In:  147.4  (I've noticed that my weight is typically up about 1 pound the day after a total-body workout.  It takes a day or two for my body to recover.)