Most of y’all know that I’ve been losing some weight lately. Thanks to the excellent Weight Watchers program, I’ve gone from an all-time high of 271.6 to my current weight, as of this morning, of 197.5. That’s a loss of 74.1 pounds.
Clearly, there are lots of figures involved, I thought I’d break down the numbers of losing weight.
No weight-loss program causes the subject to lose fat exclusively. Unfortunately, there’s some loss of lean muscle mass as well. Based on my body fat figures, I estimate that about 60% of the weight I’ve lost has been fat, with the balance being muscle. So here’s the first breakdown:
Total weight loss: 71.4 lbs.
Fat loss: 42.8 lbs.
Muscle loss: 28.6 lbs.
I started on June 20, 2005. Thanks to this nifty little calculator, I can see that I have been on this program for 267 days. That brings us to the next breakdown — weight loss over time. Numbers under a pound are expressed in ounces, and there’s a small margin of error due to rounding.
Total weight loss: 4.3 oz/day, 1.9 lbs/week, 8 lbs/month
Fat loss: 2.6 oz/day, 1.1 lbs/week, 4.8 lbs/month
Muscle loss: 1.7 oz/day, 12 oz/week, 3.2 lbs/month
As common sense will tell you, the only way to lose weight is to expend more calories than you take in. A net calorie deficit means you’ll lose weight. So let’s figure out my deficit. First, we have to convert the above figures to Metric, using yet another nifty little calculator.
Total weight loss:Â 32,386 grams
Fat loss: 19,432 grams
Muscle loss: 12,954 grams
Fat, as we all learned in high school health class, packs about nine calories per gram. Muscle is four calories/gram. So now let’s look at the losses in calorie terms:
Fat loss: 174,888 calories
Muscle loss: 51,816 calories
Total loss: 226,704
That’s a lot of calories. Such a high number that it’s pretty much meaningless, unless you break it down over time, as we did before.
Total loss/month: 25,472 calories
Total loss/week: 5,944 calories
Total loss/day: 849 calories
So I must be burning, on average, 849 calories/day more than I’m eating. How can that be? Well, let’s figure out my metabolic rate, or the total number of calories I burn in a day. The basal metabolic rate is the energy the body expends just keeping itself alive: breathing lungs, a beating heart, and bajillions of synapses firing takes energy. The commonly used formula is the Harris-Benedict equation:
BMR = 66 + (13.7 X weight in kg) + (5 X height in cm) – (6.8 X age in years)
Fortunately, I am blessed with both height and youth, which help keep the metabolic engine chugging along nicely. Thanks to yet another nifty little calculator we can see my basal metabolic rate is as follows:
BMR: 2,095.3 calories/day.
However, I like to think that my life is a bit more than just breathing. In order to find true daily energy expenditure, you have to take activity into account. In order to do that, you multiply BMR by an activity multiplier. They range from 1.2 for a sedentary lifestyle to 1.9 for someone in intense training. Mine is 1.55, defined as “moderate exercise or sports 3-5 days a week.) So, my total daily energy expenditure (TDEE) is something like:
TDEE: 3,248 calories/day.
Earlier, we established my calorie deficit to be 849 calories/day. To figure out how much I’m eating, we apply this formula:
Intake – TDEE = deficit
And we learn that my average calorie intake has been something like 2,399 calories/day, assuming the above formulas are accurate. The U.S. Food and Drug Administration bases federally-mandated nutrition labels on a 2,000 calorie diet, so it’s possible to eat significantly more than that (in my case, 20% more) and lose a whole lot of weight.
Of course, weight loss is a lot more complicated than that. You don’t just eat a raw lump of calories. You eat food, and different kinds of foods are metabolized differently. That’ll be the subject of my next post.