PAL, TEF, and predicting weight loss

Knowing your BMR is good, but it's only a piece of the puzzle of how many calories you're already spending every day without changing anything. Roughly 60% of your total energy output during the day is made up of your BMR, and the other 40% is a combination of your Physical Activity Level (PAL) and the Thermal Effect of your Food (TEF). 

To find how many calories you spend on existing and on your current activity level, multiply your BMR by the Activity Factor that best describes your lifestyle:

AF 1.2 = Sedentary (no consistent exercise)
AF 1.5 = Slightly Active (light exercise 1-3 days per week)

AF 1.8 = Moderately Active (job includes standing with some walking; moderate exercise or sports 3-5 days per week)

AF 2.0 = Very Active (Job includes walking; strenuous exercise or sports 6-7 days per week.)

AF 2.2 = Extremely active (physically strenuous job; very strenuous exercise or sports)

Personally, I walk a few miles at a brisk pace 5 mornings out of the week. That puts my activity factor at 1.8. As we discussed yesterday, my BMR is 1856.875. That means that in order to exist, and to keep up with my current level of activity, I need 3342.375 calories. 

Does that seem like a big number? It is. I'll explain later. 

The second number we're looking at today is the Thermal Effect of Food (TEF). This number refers to the number of calories required to digest the food that you're eating. The math for this isn't complicated, it's just 10% of your total calorie intake in the day. 

At maximum, on a really *really* off day, I take in 1500 calories. Most days I'm closer to 1000 or 1100. For today's purpose (and to not inflate numbers here), I'm going to use the smallest number in my factor. Ten percent of 1000 is one hundred. 

Add your TEF to the number you got from multiplying your BMR by your activity level. That brings my number to 3442.375. 

To exist, exercise, and eat, I burn 3442.375 calories per day. 

Here's where I'm going to use an assumption that is currently under suspicion in the scientific community. I'm going to assume that burning off one pound of fat requires your calorie input to be 3500 calories lower than your calorie output. There is an explanation of why this long-held assumption is under question right now as well as a calculator to predict your weight loss on a variety of factors and a very complicated math equation. However, as I mentioned, this is all very complicated. So I'm going to go with the long held and probably not entirely accurate assumption that 3500 is the number of calories to burn if you're going to lose a pound. 

Now, assuming this, let's take a look at my current output. Taking in 3500 calories less than I burn every day is physically impossible (if I'm not going to resort to starving myself), which means I'm not going to lose a pound every day. Shucks, but oh well. No biggie. However, I do currently take in at least 1900 calories less than I naturally burn every single day. That means that every two(ish) days I'll have taken in 3500 fewer calories than I burned in that two days and thus lost a pound. 

Sure, this doesn't take into account any kind of muscle gain, but it's pretty cool and very encouraging. Especially at the beginning of your journey it can be very helpful to know what you can expect. Keep in mind that as you lose weight your BMR will go down, and thus the number of calories you burn overall will also decrease - which mostly means that you will not be losing weight at the same rate in a year as you are this week. 

Today, calculate the number of calories you burn using your BMR, PAL, and TEF claculations.