Q: I have faithfully done 20 minutes on the elliptical machine every morning and evening for three weeks, but the number on the scale hasn't moved. How long before I shed pounds?
— Penny Barnes, Clear Lake, Iowa
A: Weight loss is about calories in versus calories out. So the first question to ask yourself is how hard you're exercising. Perhaps you need to raise the intensity level, step up the pace with some good music, or pump your arms harder. A good workout should involve a notable increase in your heart and breathing rate. The second question is whether you're eating more to meet your new, higher energy demand—if so, the scale won't budge. But here's another consideration: You may be building muscle, and that's what's throwing off the weight loss equation. You can burn a lot of calories and lose fat, but when you put on lean muscle—because it's denser than fat—you often get leaner without getting lighter. Are your clothes looser? Do you look thinner? Are you more energetic? The exercise has almost certainly made you fitter and healthier. Don't let the scale talk you out of these important results.