If you spend long hours working at a desk, your job may be expanding your waistline. But now research at Kansas State University shows a way to activate an enzyme in your body to burn off more fat as you work. When you sit unmoving for hours at work, and your muscles are dormant, you switch off a natural chemical in your body called lipoprotein lipase, or LPL, says researchers . Lipoprotein lipase stimulates the cells to take in fat or triglycerides and use it for energy. To get LPL going again, take more breaks fromsitting and move around the office. Work standing up. Pace back and forth every 15 minutes or half hour. Not only do people need to be more physically active by walking or doing moderate-to-vigorous physical activity, but they should also be looking at ways to reduce their sitting time .