Many people that exercise regularly and eat right still complain about not being able to lose weight. They don't understand why they're not losing, but many times the reason is simple: low metabolism due to a lack of muscle mass.

I think one of the main problems is that people have a fundamental misunderstanding of exercise, especially in terms of what is required for weight loss. First of all, there are two basic types of exercise: aerobic and anaerobic. Aerobic exercise (meaning with oxygen), is exercise where you move your body at regular relatively slow to moderate levels for extended periods. Examples include activities such as walking, jogging, swimming and bicycling. This type of exercise has a number of benefits including strengthening the heart (thus lowering the risk of heart disease), improving lung capacity, controlling weight and increasing flexibility. What aerobic exercise generally does not do is tone or build muscles. For this you need anaerobic exercise. Anaerobic exercise is exercise that is sufficiently intense (i.e. moderate to high in intensity), and lasts no more than a couple of minutes of sustained effort. Because it is anaerobic, the individual muscle cells are purposely damaged through a process called overloading. Overloading is not a bad thing though! The body reacts instinctively to overloading and repairs the damaged cells so they can cope with any future overload. In so doing, the size and strength of the muscles is increased. Examples of anaerobic exercise might be weight lifting, resistance training, sprinting, spinning, etc. Note that although each individual anaerobic session will be relatively short in duration, the body recovers quickly, thus repeated sessions may be done to give a longer term anaerobic workout. (That actually tends to be a combined aerobic and anaerobic workout because the body goes aerobic inbetween anaerobic sessions.)

Let me back up a minute here and explain why aerobic vs. anaerobic exercise is confusing for people. When the body needs energy, it can use various sources such as carbohydrates, protein and fat, but only a small amount of ready energy (generally in the form of glycogen), is stored in the muscles for ready energy. If during aerobic activity this store is depleted, the body is able to convert fat stores into usable energy. Thus during aerobic exercise you start burning fat after a certain point depending on how much glycogen is present in the system. With anaerobic exercise, you are not metabolizing fat, thus it sounds like aerobic activity would be the way to go for fat loss, right?

Wrong. The fat burning cycle of aerobic activity stops fairly quickly (often as soon as the glycogen stores are returned to normal). Because anaerobic activity builds muscle mass, it actually has a greater effect on weight loss than does aerobic activity. Why? Well, it's because muscle cells have much greater caloric needs than do other types of cells such as fat cells. (Remember, fat is primarly inert, unlike muscle that is active.) Thus as muscle mass is added, your metabolic need increase, meaning you burn more calories simply sitting still! Plus, recent research shows that exercises like weight training have a much longer effect on resting metabolism after the completion of the exercise routine than do aerobic activities.

Plus, whether you realize it or not, excessive aerobic activities can actually lead to decreased muscle mass. Don't believe it? Look at the bodies of the average marathon runner vs. the average athlete. Many marathoners generally have very little fat, but they also, for lack of a better word are scrawny. They simply have very little muscle mass and thus their resting metabolism is fairly slow compared to many other athletes. The only thing that keeps them from becoming fat is the sheer amount of time they spend burning calories.

So, what is the best kind of exercise to do for fat loss and overall good health? Actually a combination of aerobic and anaerobic exercise is best. In addition to the conditioning benefits of aerobic exercise and the muscle building of anaerobic exercise, a combined program will provide:
Greater Decrease in Body Fat
Increased Cardiovascular Function
Increased Muscle Mass
Improved Strength
Improved Power
Improved Speed
Increased Aerobic Capacity
Increased Endurance

How long you exercise will depend on your goals, schedule, and physical condition, but most recommendations are to get at least 20 minutes of aerobic exercise 3 times a week along with at least two 20-30 weight lifting or resistance sessions to receive the most benefit.

I know some of you are thinking that this must be wrong because you've been told in the past that aerobic training was the best way to lose fat. It's true, you CAN lose fat with aerobic training, but you may also lose muscle mass leading to decreased metabolism. Overall, this will make the weight come off more slowly and have you looking thin and sickly instead of toned and healthy.

Keep in mind that the ultimate goal for all of us is better health. Virtually all experts will agree that the best route is through a combination of both cardiovascular and resistance training.

You read my mind.. I am trying to shift a few lbs, and have wondered why walking more doesn't seem to make an ounce of difference! HUh! Now I know..

OK, I'll do a little weight stuff too. I do have low muscle mass.

Thanks for the post!

Hello Thanks so much again for the great info I have been also trying to loose more fat mass and stablize the lean body at the same time keep it all safe. The amino acids I have been takeing in the month of Febuary I believe attributed to a a great fat mass loss and kept the lean muscle in check, still reseaching this. January, I lost lean and fat mass but In Febuary I lost a lot of fat and gained a little lean muscle back so your info is very helpful. Thanks again and have a great weekend!!

Hi just thought I'd drop you a quick note to say congrats on the blog, top drawer. If you have time thought you might like to look at my Aerobic Activity site and let me know what you think.