Friday, June 12, 2009

Losing Some Weight - Part 2

Yesterday I talked about understanding the output side of the calories out > calories in equation. We went through Sparkpeople's method of calculating my daily caloric needs based on BMR and activity level.

Now, let's talk about losing weight. In it's simplest form, one pound of weight equals 3500 calories. So, burn 3500 more calories that you eat, and in theory you lose a pound. Want to lose a pound a week? Eat 500 fewer calories than you burn each day. Want to lose a pound a month? Eat 120 fewer calories than you burn each day. We now have what we need to figure out how to lose the excess that we are targeting!

Let's do this old school. First off, we'll use my data. My BMR is 1950 calories. Adjust that for a sedentary lifestyle (basically sit in my office) - puts my daily base calorie needs at 2200 per day. Now, we need to adjust for exercise. I run a little over 35 miles per week. Estimating 100 calories per mile (or 3 miles per donut), I burn around 3500 calories per week. Add about 500 more cross training, and I get 4000 per week exercising. So - the equation looks like this:

Total calories out = (2200 cals/day X 7 days/wk) + 4000 = 19400 cals/wk

So, to maintain my current weight at my current activity level, I would need to eat around 2777 calories a day.

Now, I've targeted losing 15 pounds over the next six months. Assuming that six months is 180 days:

Daily calorie deficit = (15 lbs X 3500 cals/lb)/180 days = 333 cals/day

So, to lose 15 pounds at my current weight and activity level I would subtract 333 calories a day from the 2800 calories above, and I arrive at 2444 calories per day. Pretty close to Sparkpeople's calculations:

Now it's a matter of being religious and tracking the food that you are eating.

Sounds pretty simple huh? Well, let's talk about the reality of the situation. First off - all of these number are estimates. They are calculations over a population. They are not exact for Glenn Jones. Second, note the italicized letters. These calculations assume maintaining my 4000 per week calorie burn and my current weight. These are important points - as my weight decreases, my BMR will decrease. Likewise, if I reduce my weekly exercise level, then I need to adjust my exercise numbers accordingly. These two reasons are most often why we start losing weight aggressively only to plateau. More on that tomorrow.

Yesterday I did put in my miles. 9 miles in a *slow* 10:01 pace. Average heart rate was 79% of max. I'm really tired. I'm not fueling properly. Time to start eating right again.


  1. What's interesting to me, though, too, is that the latest research is implying a more complicated relationship than "calories in/calories out."

    My personal experience: Even though I've successfully lost a lot of weight on my current plan, I literally was not losing weight While Consuming Fewer Calories in the past. So, while calories in/calories out is definitely a place to start, I do think there's something else to it.

    Gary Taubes' "Good Calories, Bad Calories" is sometimes miscategorized as an apologetics for low-carb diets -- but that's inaccurate. It is definitely against processed foods, however. And it's definitely worth a read.

  2. The tracking the food part is what's tough for me. I'm terrible at estimating what an ounce, or a 1/2 cup, or "a serving" is...I'm pretty sure that's what gets me into trouble.

    Oh, that and wine :-)

  3. I'm quite lucky to chance upon your very interesting and informational blog. I'm short but close to 200 lbs, so I find it hard to improve on my times and increase my mileage. I hope to be at 180 lbs. when I run my first marathon last week of September. I need all the help and your posts seem to give valuable suggestions on how I can achieve my goal. Thanks and good luck on your running too.

  4. I have been tracking my calories for the last two weeks and its funny to see how much fat/cars/protein is actually in stuff. I read something that if you reduce your calorie intake then your body will adjust to that amount of calories and learn to run on that amount. I am currently eating about 1400-1800 a day depending. Not that I want to lose weight but will my body adjust and if i start to consume more calories will I then gain weight???

  5. Hi Glenn! My blog (tri blog) is still up- but for some reason it wasn't displayed on my profile. I fixed it so come and say hello! Christine

  6. good luck! last night i was tempted to have some more m&m's or sun chips before bed but then i was too lazy to log it so i didn't. hey, whatever works right?