I've always though of the "calories in vs calories out" technique for weight loss to be the starting point for the majority of people trying to lose weight. Reign in how many calories you're eating, start burning a few more (even just walking a block or two for most people is a great start) and you'll see significant weight loss over a long period of time.
Don't beat yourself up when you have a "bad" day, because the success of this technique is not measured in days. It's not even measured in weeks or months, it's measured in a unit of "the rest of your life".
After many months tending to years of this, and many pounds lost, the approach can be fine tuned and what is being eaten can be examined in slightly more detail.
Once you've mastered crawling, you can move onto walking and running, but it's simply too difficult to jump straight into running where there are so many gains to be made from simple crawling.