24-Hour Fat Burning?

As the old saying goes, "If it sounds too good to be true, it probably is." And, sadly, such is the case with the widely held belief that a thorough workout enables one's body to effectively burn fat for the next 24 hours, report University of Colorado, Denver, researchers in the journal Exercise and Sport Sciences Reviews. "Moderate-duration exercise of an hour or less has little impact on 24-hour fat oxidation," lead researcher Edward Melanson, Ph.D., told WebMD.com. The main reason for that? You'll eat during those 24 hours. "It's not that exercise doesn't burn fat," he continues. "It's just that we replace the calories. Exercise increases the capacity to burn more fat, but if you replace those calories, that is lost." So instead of banking on that rigorous workout to keep you losing weight all day, it's wiser to focus on "calories in, calories out," and expend more than you're taking in, Melanson advises.