It’s a nice thought—and people definitely try. But, sadly, you can’t exercise off a crappy diet. Science backs it up. In one study—literally entitled: “It is Time to Bust the Myth of Physical Inactivity and Obesity: You Cannot Outrun a Bad Diet”—published last year in the British Medical Journal, researchers confirmed this, and also argued the over-emphasis on physical exercise at the expense of dieting encourages manufacturers to create a “health halo legitimization of nutritionally deficient products.”