I find it interesting that some people have denounced walking as completely ineffective for weight loss. While running burns about twice as much energy (or more) per unit time compared to walking, the amount burned per unit distance is very similar with running only using 10-20% more energy. If you are severely restricted on free time than running is obviously better, but I find that I can walk much more than twice as long as I can run. I try to walk at least 5 km a day and I notice that for longer periods when I can stick to that I feel better and lose a bit of weight, whereas when I don't do as much walking I feel more lethargic and the weight starts (ever so slowly) creeping up. The thing is, I never really feel tired after a 5 km walk, whereas a 5 km run leaves me drained for a long time. I've never really been overweight much and I attribute that in part to the walking I do, since I do almost no food restriction and only small amounts of more intensive exercise.