3. You burn more fat by exercising longer at a lower intensity – the myth of the ’fat-burning zone’.
No, we burn a higher percentage of fat as a fuel source when working at lower intensities, but we burn more total calories when exercising at higher intensities. At the end of the day, it’s calories in versus calories out that matters.
Of course burning calories will cause a shift in your weight...But you DO burn more fat at lower intensities or in the fat burning zone. (you said it yourself, higher percentage). And the "myth" you wrote was in relation to fat, not calories. So, if you want to burn more calories and lose more weight at a higher intensity than your zone, well, you are losing muscle as well...
...Think of it this way...Who has the more lean muscle mass. Sprinters or long-distance runners? Sprinters...Long-distance runners appear thin, but have a much higher fat content due to running at higher intensities for prolonged period of times. Sprinters have lean healthy muscle mass and don't waste their muscle stores.