Make the change! It’s time if you’ve been putting it off; if you’ve tried and failed many times - give yourself a chance at a better life. I’ve already described how to count calories and how to determine your fat-burning heart rate zone. Let’s see how you can use this information. First, let’s take the simple rules I built (and still build) my lifestyle change on: try it; analyze it; if it works, adopt it; and start over.