Unfortunately, despite the hype, marketing and celebrity testimonials, ramping up your metabolism is mostly a myth. “To make a long story short, there is very little hope of changing your resting metabolic rate, because you’re fighting your biology,” says Eric Ravussin, director of the Nutrition Obesity Research Center at the Pennington Biomedical Research Center in Baton Rouge.

To understand why trying to speed up your metabolism is mostly a waste of time and money, let’s start with some physiological facts.