How Many Hours, How Many Miles....?

I am pleased that the good people at Fitness for Weight Loss have compiled easy to follow guides telling us how many hours a person must endure a given exercise to lose one pound. While helpful, the tables should be thought of more as rules of thumb than scientific cannon.

I considered compiling a table similar to the aforementioned lists. But then I reconsidered. The aforementioned rule of thumb is that a pound of flesh equals 3500 calories. So if you burn 3500 calories, you shed a pound. Hold on a second. Should we not figure the marginal calorie burn? The difference between say, walking and sitting?

Let's borrow a few numbers from the Harvard eggheads.
Note: For simplicity sake, only estimated calories for a 155 person are included.

Note: The calories burned are figured for one half hour. So we have to get out our calculators and multiply by two to get hourly rates. 

Note: 3.5 mph is a fast, non-leisurely pace. It's more of a power walk pace.

Observation: Do you really burn 28 more calories per hour by reading vs. watching TV? Well this is Harvard and when they read, they really read, man. Plus, their TV viewing only includes C-SPAN and PBS, material that does not necessarily induce laughter or bodily movement or changes in facial expression.

Walk: 3.5 mph (17 min/mi)

149

Sleeping		23
Watching TV		28
Reading: sitting		42
Standing in line		47

So, should we not subtract the calorie burn of say, watching TV, from the calorie burn of walking? Instead of counting total calories burned, should we not count net calories burned? Walking at 3.5 mph burns 149 calories per half hour but only 121 net calories (or 107 calories per half hour should one indulge in Harvard-style reading.)

The point of all of this is: It takes longer to burn off a pound than even the dismal tables suggest. If the dismal table tells us it takes twenty hours of said activity to lose a pound, it might actually require thirty hours of said activity. Bummer.