Transcript: Thirty minutes isn't that long-it's less than a class or an episode of The Office.  It's also all the time you need to lose weight. If you're ready to change your body for the better, you can start with this simple step: commit to a daily thirty minute workout. When weight loss is your goal, spend your half hour engaging in aerobic exercise. Aerobic means “with oxygen,” and refers to an exercise that can be maintained over a period of 20 minutes or more.  While exercising aerobically, you should be able to carry on a brief conversation without gasping.  Some of these aerobic exercises include brisk walking, jogging and cross-country skiing. Group exercise can also be aerobic,  like spinning, kickboxing and step-classes.  During aerobic exercises like these, the body takes glucose that it has created from food and uses it for energy. Once you use up your supply of glucose, your body uses its stored fat for the energy it needs instead. This is why daily aerobic activity leads to weight loss. Of course, this kind of exercise has a host of other benefits,  like reducing your risk of heart disease and stroke, and even improving your mood. Commit to doing aerobic exercise daily, and you'll definitely start seeing results within three to four weeks.