No doubt you're inspired to lift weights by the photos of lean, sculpted celebs you see in your favorite checkout-line magazine. You've finally gotten over the notion that weight lifting makes you bulk up like a female version of He-Man, and realize that it helps improve muscle tone and appearance. While lifting weights helps you burn the fat covering your muscle, it does not convert that fat into muscle.
Fat vs. Muscle
Just like you cannot turn an orange into an apple no matter how you cut or cook it, you cannot turn a fat cell into a muscle cell no matter how heavy or often you lift. Fat and muscle are two totally different types of cells, with very different functions. Fat cells store energy, while muscle cells are responsible for movement. In addition, your body has a set number of both fat and muscle cells; the numbers don't change but the cells can change size.
When it comes to losing fat, it's all about calories. Fat cells grow in size when you eat or drink more calories than you burn. So to lose fat, or really shrink the size of your fat cells, you need to eat fewer calories than you burn. One pound of fat contains 3,500 calories. You can lose 1 pound of fat a week if you decrease your daily caloric intake by 500 calories, and as you lose the fat you'll see more muscle definition. When trying to lose fat weight, it's better to lose it slowly. Losing weight too quickly, more than 2 pounds a week, means you're losing muscle and water.
Lifting weights helps increase the size of your muscle cells. The more muscle mass you have, the more fat calories you burn. This is because working out your muscles increases mitochondria development. Mitochondria are the powerhouses responsible for turning that excess fat on your thighs into energy your muscles need to lift those weights. More reps means more mitochondria. If you want to get lean, it's better to lift lighter weights and do more reps.
Maximizing Fat Loss
Lifting weights cannot turn fat into muscle, but you can speed up fat loss and help get better muscle definition with exercise. Interval training is a type of cardio exercise that includes high-intensity exercise followed by periods of rest that not only helps you burn more calories while you're exercising, but also increases your metabolic rate after your workout. If you're a walker, you can alternate three to four minutes of jogging followed by two minutes of walking to help you burn more fat. Consult your doctor before making any changes to your exercise routine.
Jill Corleone is a registered dietitian and health coach who has been writing and lecturing on diet and health for more than 15 years. Her work has been featured on the Huffington Post, Diabetes Self-Management and in the book "Noninvasive Mechanical Ventilation," edited by John R. Bach, M.D. Corleone holds a Bachelor of Science in nutrition.