Like most Americans, you’d probably like to decrease your body fat. While you may realize that exercise will help you lose weight, do really know the science behind the process?

The fundamental truth is this: you lose weight when you take in fewer calories than you use. Of course, that doesn’t mean that if you eat 1600 calories during the course of a day that you have to exercise away 1600 in order to lose weight. Your body constantly burns calories. In fact, it’s burning calories as you read this. By merely being alive you burn calories, and you burn even more when you do things, like walk or drive or talk. To calculate how many calories you use on a daily basis, use Beachbody’s Caloric Needs Calculator or the manual method, that is explained in this article.

If you want to lose a pound of fat, you have to burn 3,500 calories. That doesn’t mean, of course, that you must do it in a single day! About a pound a week is easiest and healthiest. Therefore, in order to decrease your body fat at a slow, safe rate, create a deficit of 3,500 calories per week. The easiest way to do it? Cut your caloric intake somewhat and incorporate exercise into your daily routine.

Exercise, combined with a decrease in calories, will help you lose body fat. When you elevate your heart rate, your body uses more energy, such as the energy you have stored in your body as fat. Aerobic exercise, also known as cardio, can really get your heart rate up. Dancing, cycling, swimming, running, and walking briskly are all good low-impact, calorie-burning, cardio exercises that will help you lose weight.

Exercise can also help you lose weight by making your body a more efficient fat-burning machine. When fitness experts and nutritionists use the term “metabolism,” they simply mean the amount of calories your body burns when it’s at rest. Muscles—even at rest—burn more calories than fat, so if you increase your muscle mass, your body will use more energy even when you’re sleeping. To increase your muscle mass, commit yourself to strength training.

Strength training that adds muscle, combined with cardio workouts to increase your heart rate, will drastically increase your body’s fat burning; in other words, you’ll lose weight much more quickly than you would through dieting alone.

While you’re losing weight through diet and exercise, you’ll be building muscle. For this reason, your bathroom scale might not reveal your true progress; however, your measurements will. To track your progress even more accurately than with a scale or a tape measure, monitor your body fat percentage with a body fat caliper, such as the P90X body fat tester. This easy-to-use device is reasonably priced and readily available.  If you’re looking for a couple of good exercise programs that incorporate both strength and cardio, consider Power 90 for beginners or P90X if you are currently working out on a regular basis.  You can always look over our program comparison guide as well.  Whatever you decide, good luck, and let us know if we can help!