It's definitely possible to lost weight simply by walking more. It's impossible to give you a flat number on how many calories are burned by walking, though, because there are a lot of factors that go into it. Your weight and the speed you walk both change the number of calories burned per mile, as well as any additional exercise you add in, such as pumping your arms or adding leg weights.
The good news is that the heavier you are, the more calories you burn by walking. A three hundred pound person will burn triple the calories that a one hundred pound person would by traveling the same distance and the same speed. In addition, the faster you walk, the more calories you burn. That same three hundred pound person will burn fifty calories more per mile traveling at five miles per hour than he would at two miles per hour.
The information you're looking for is the "metabolic equivalent" of walking. About.com has a good calculator for figuring that out based on your size and speed, found here: http://walking.about.com/library/cal/uccalc1.htm.
Just push yourself a little; if you currently drive everywhere, see if there are a few places you could walk to instead. Take a walk in the morning, or just move! It's healthy.
Posted 1196 day ago