Of course it's a lie. These are all gimmicks to reduce fat and cheat money. Burning fat is just an attractive advertising word. To really lose fat, you need persistent and scientific whole-body exercise. Reducing fat (or losing weight) can't be compared horizontally, but only vertically with your former self. Different people have different absorption capacity and metabolic rate, so their bodies can't be compared. If you are really overweight, keep exercising.