I spend some effort managing my weight. One of the things I do, that most people can also do, is walk. Walking can buy you a free lunch, calorie-wise. Here’s the deal…

First off, it’s useful to know that the average walking speed for an adult is 3.1 miles in an hour, and that walking one mile burns pretty much the same number of calories that running one does. That’s because the physics for “work” basically boil down to moving mass through distance, without any factor for how quickly one does that. So walk, don’t run. Gives your body more time to deal with the waste toxins produced by your muscles, which is definitely a win.

A rule of thumb for walking one mile is that it will burn about 100 calories for a 180-pound person, or 65 calories per mile for a 120-pound person. So, if you weigh 180 pounds, walking ten miles burns 1,000 calories, which might be a nice lunch, for instance. And since we know the average walking speed is 3.1 miles per hour, we also know it’ll take you about three and a half hours to walk ten miles.

Something else useful to know if you live in a town or a city is how long a trip around a block is. A standard city block is

More generally, what I suggest you do is measure your block, or whatever path you like to walk, using a GPS. Find out how many feet that is; then divide 52,800 by that number, and that’ll tell you just how much walking you’ll have to do on it to get to 1,000 calories.

Also be sure to take your weight into consideration; all my numbers were derived for a 180 pound person. If you weigh less, you won’t burn as many calories, or you’ll have to walk further. If you weigh more, you will burn more, or you won’t have to walk as far. If you want to burn a different number of calories… well, you’ve got some math to do.

Once you’ve done the math, though, this is a nice way to work on your health and your weight and get to eat more in the bargain. A few hours in the morning, some great music in your earbuds, and… a free lunch. So much for TANSTAFL.