I agree that there are some very efficient ways to burn calories and fat. And some will build muscle at the same time.
But the average unfit/overweight person will find the thought of a special plan daunting. Walking and swimming are both low impact excercise that can and do increase fitness, burn calories and build stamina. I read an interesting article re the body only burning fat after 20 mins a couple of years ago.
It basically agreed that though the most efficient way to do this is to increase your heartrate sufficiently for a set period of time. After you have reached this heartrate and done the required time your body begins to convert fat stores into energy which are burnt off or something along those lines.
However it then went on to say that walking burns more calories than sitting. So if you walk more you burn more calories. It may be the calories you have eaten recently and not had chance to lay down as fat but if you don't lay down as much fat then surely you will maintain your weight? Then add to that the fact tha your muscles will increase if you do more walking, muscle burns more calories than fat so overtime you will use more calories just sat the more walking you do?
There was lots of science behind it. But the main message it was trying to get across was move more and you will loose weight eventually. Or at least increase the amount of muscle you have and reduce the amount of fat you are carrying.
In an ideal world then everyone would be interested and clever enough to have a personal fitness plan that they had the time and resources to pursue. Many people don't, or perceive that they don't which gives the same end result.
If I don't have enough time/money/understanding/the right gear to do 25 minutes 5 times a week of the right kind of excercise then there is no point doing any and I may as well use the car to do the school run/nip to the shop etc etc.
The way I see it anyone can go for a walk at any time. Whether it be for 10 mins or 2 hours. Whether they are able to increase their heart rate to the desired numbers or not. Telling people there is no or very little point in doing this is not actually that helpful.
I notice at my DD's school that the mums that walk to do the school run are generally slimmer than those that use their cars. I know unless I make an effort in the holidays to walk a lot I will put on 3/4 lbs by the time they are back. So I know for me that walking works, keeps me fit and keeps the excess lbs off.
And it gives people confidence too. If they can walk 2 miles a day, then they may manage a class at the gym, or to be able to walk the Run for Life events, or even take up cycling or running.
You have to walk before you run is certainly true IMO.