(Ignoring all other replies in this thread.)
Here’s what I learned:
Walking is crap exercise. Sure, it beats couch-potatoing, but it’s still not a very efficient way to burn calories. Even at a pretty quick pace (4mph), walkers still don’t burn that much. I walked for about a year before I just gave up on it as exercise. I found other forms of exercise and one thing included a lot of resistance/weight training. And once I had a regular regimen of training that required me to build muscle (and not just work the heart, lungs and feets with walking), then 40 pounds melted off me like magic.
A little research helped me make sense of that: At rest, while you are sleeping, your muscles go into repair activity, which requires protein. (So, #1, healthy eating). As damaged, sore, tired muscles go about the business of repairing, they build up new tissue from all that healthy lean protein you’ve been eating, so you build up muscle. Fat does not burn fat. Muscle burns fat – it uses that fat for fuel when it runs out of bioavailable protein. Fat is just calories stored, but muscle is what uses up all the calories taken in.
The more muscle you have, the more fat you burn. At night. While you’re sleeping. (#2, sleep regularly and well) (and #3, you need resistance training as much as you need cardio.) This is why men tend to lose weight faster than women do – because they generally start out with more dense and more muscle tissue, which uses up more fat stores faster – and women carry more fat on our bodies in general because babymaking.
I think a big mistake many people make in weight loss efforts is thinking of it as only a two-pronged approach: 1) eat well and 2) do cardio. I say a four-pronged approach is more effective, and I learned that from my own personal experience, YMMV and so forth, but that is 1) eat well/less, 2) do cardio, 3) resistance/weight/strength training, 4) sleep well and regularly. (and 5. drink more water than other stuff)
I’ve seen studies (google yourself) that directly link good sleep habits to weight loss. Your metabolism and your circadian rhythms are a single system that works together. Screw up one and you’ll also have problems with the other.