Walking can be good for weight loss, but it's not the most efficient way to lose weight. Walking however is one of the best things you can do to lower your "set point".
If you don't know what your set point is, you will need to continue reading to find out why it's important to losing weight and keeping it off.
First off, overall, walking is a bad choice of an exercise for burning calories and fat directly. It's just not intense enough to ellicit a powerful weight loss reaction from your body.
Walking isn't all that bad. Walking is actually the best or one of the best exercise you can do to lower your set point.
What is your set point? It's the body's zone of comfort for what your weight should be. A lot of times people lose weight, but they fail to lower their set point. What happens then is they regain all the lost weight since the body isn't yet comfortable at that new weight.
Walking helps to solve that problem. Walking lowers your set point. Research really can't pinpoint why walking is so effective at lowering your body's set point, but it does.
So if you're starting to lose weight, you should add walking so that your set point also goes down with your weight. When they are both going down at the same time, weight loss is sustained and you keep the weight off for good.
So walking is good for sustained weight loss, but moreso because it lowers your body's set point rather than directly burning calories.