by M. Doug McGuff, M.D.


The primary reason most of us start an exercise program is to improve our physical appearance. While there are more important reasons to exercise, there is not a more powerful motivator than improving our physical appearance. While we should exercise for our health, we probably wouldn't unless we look better in the process.


While this sounds vain, it actually isn't. Our major duty as a living organism is to serve as a transport device for our DNA. Our genes' major concern is to use our body as a mechanism for propagating themselves through time. Sexual reproduction is how our genes ensure their replication through time. A major determinant of an animal's sexual attractiveness is its general appearance of health. Strength training is the most efficient way to create a body image that broadcasts health. So while working out to look better might seem superficial, it is really quite fundamental. The appearance of our bodies drives the survival of our species, and thus our genes.


Factors that Determine Body Shape


There are basically three elements that determine our body shape. They are: our skeleton, our muscle and our body fat. The skeleton is just the framework upon which the other two elements hang. While it is critically important, it cannot really be altered. Every desirable shape on the human body is accounted for by underlying muscle. Every undesirable shape on the human body is accounted for by body fat. Setting aside personal taste, the female breast tissue may be a notable exception. However, whether the shape of this fatty mass is desirable or not depends largely on the condition of the underlying pectoralis muscle. If the pectorals are well conditioned it will exhibit the underlying tonus that will support the breast tissue in a pleasing shape. Many breast implants designed to improve breast shape involve placing a prosthesis underneath the pectoralis muscle. By adding mass to the existing muscle and pushing it forward, it provides tension and shape to a breast that is sagging. The prosthesis provides the effect that an otherwise properly developed muscle should provide.


We can see that the major way we can produce an improved appearance would be to add muscle mass and lose fat mass. The type of exercise recommended in this book is the best way to achieve this goal. Proper strength training will provide the stimulus to add as much muscle as a person's genetics will allow. For most people, this will be a rather modest increase. For a very few people, significant increases in muscle size may occur. These large increases in muscle are confined mostly to a small subset of males; it is extraordinarily rare for women to gain large amounts of muscle mass. Fat loss is largely going to be achieved by dietary restriction. Despite all the diets that are focusing on macronutrient ratios, the common denominator in fat loss is still the production of a calorie deficit. Exercise has been touted as a great calorie-burner, but it really is not. Even with SuperSlow, not many calories are burned above baseline during a workout. The production of muscle does have an effect that we can take advantage of; we will discuss this under the heading of Fat Loss below.


The Limits of Muscle Growth


With a properly managed program of SuperSlow, increases in strength can be quite dramatic and continue almost infinitely. As a subject becomes more advanced, strength increases will come in very small increments, but they do keep coming. Increases in muscle size are finite however. Initially muscle growth occurs rather predictably, but will soon stall or even stop. Some individuals (mostly men) will produce rather startling increases in muscle size, others produce very modest increases, and some produce minuscule increases in muscle size. So while everyone can get a lot stronger, not everyone can have a bodybuilder physique.


We in the field have always known that genetics determined who could be extremely muscular, but we were not sure how or why this occurred. The how we will discuss momentarily, I will now give my opinion as to why muscle growth has varying limits. More strength is almost always an improvement (unless the muscles got so strong that they exceed the bones' structural integrity). The increase in mass that goes along with increases in strength can become a very negative thing. As you increase a muscles dimensions, volume will increase in the third power, but surface area will increase only to the second power. Body heat is generated in proportion to muscle mass or volume, body heat is dissipated in proportion to body surface area. So if you doubled muscle mass, heat production would go up by a factor of 8 (2 X 2 X2), but heat loss would go up by a factor of only 4 (2 X 2). Therefore, cooling efficiency would go down by half. So for a doubling of muscle mass, your cooling efficiency would be cut in half. As muscle is gained, the advantage gained is offset by an ever escalating loss in cooling efficiency. Recently, some collegiate and professional football players have died of heat exhaustion during summer training camp. The 180 pound wide receivers never keel over, it is always the 300 pound linemen who die. The problem of heat production being related to volume and heat loss being related to surface area explains why. Simple math shows that the larger player can only tolerate 21% of the heat stress that the lineman can. There are other reasons the body might want to limit muscle growth, but this is the major one in my opinion. The severe calorie demand that this tissue makes is another, as are mechanical and structural issues. It is clear that the body has devised some genetic means of regulating the muscular growth process.

The answer to this dilemma comes from the field of animal husbandry. Ranchers in Belgium have limited open land on which to raise cattle. In order to get more bang for their buck, they began to breed cattle for increased muscle mass. Over time, they were successful in breeding cattle that have three times the muscle mass of a normal cow. The breed was named the Belgian Blue and is pictured below.


Note that this animal is not exercised in any way to produce these massive muscles. Researchers in Belgium isolated a genetic variation in this breed. This animal was missing a gene called GDF-8. This gene produces a protein called Myostatin. What myostatin appears to do is limit how large a muscle can become. It is the regulator that places a limit on how large a muscle can become as a result of normal growth, or as a result of exercise. When this gene is lost, either by accident or through breeding, the animal in question will have unusually large muscles.


The action of this gene was confirmed by Dr.'s Li and McPherron at Johns Hopkins University when they successfully deleted the gene in mice. In the photos below you can see the difference in mice who have their myostatin gene intact versus those who have had their myostatin gene deleted.





Recently, a deletion of myostatin has been reported in a champion bodybuilder who submitted himself for testing. It is highly likely that many champion bodybuilders possess some form of genetic mutation that eliminates or down-regulates their myostatin production. While this may prove horribly disappointing to some frustrated bodybuilders, it will prove reassuring to the majority who do not desire overly large muscles. It should also cause us to look with a jaundiced eye towards supplements and products endorsed by those in possession of this genetic anomaly.


Myostatin is not just something that is present or absent. It is present in the vast majority of the population, but probably exerts its effect to different degrees in different people. In some people its effect may be small, and it may allow fairly generous muscle growth. In others, it may have a larger effect which will produce only modest muscle growth. In any given individual, the amount of expression of this gene will have been determined by natural selection through his or her gene line. The degree of myostatin that an individual possesses will thus be ideal for their overall genetic makeup. As you go become stronger, you will also have an increase in muscle mass that is ideal for your genetic makeup. It may not be as much or as little muscle as you desire, but what happens will be the most ideal adaptation for you as an individual.


Fat Loss


Losing excess body fat will have an even more dramatic effect on your appearance. As a matter of fact, losing a pound of body fat will have three times the effect as gaining a pound of muscle. This is because muscle is dense tissue. Fat, however, is not dense. A pound of fat occupies 3 times the space that a pound of muscle will. Think about a pound of steak at the grocery store how big it is; a pound of fat will occupy three times that space. Muscle growth will have some effect on shape, but it is more important in providing underlying tone. Stripping away overlying body fat will have a very dramatic effect on body shape and will reveal your hard-won underlying muscle. The only limitation in losing body fat is the necessary discipline.


The laws of thermodynamics state that energy cannot be created or destroyed, only changed in form. The human body is not exempt from this law. Body fat is simply energy is stored form. If we are to lose fat, we must mobilize those energy stores by creating a calorie deficit. In the absence of food energy, body fat is used for energy, and some heat is lost in the process due to the minor inefficiencies in the process of fat mobilization. Recently, there has been a lot of hype regarding types of macronutrients and fat loss. Some programs restrict fat, others restrict carbohydrate, and some recommend fixed ratios of different macronutrients. While all of these may prove successful, they will only do so if there are fewer calories consumed than there are calories expended. Caloric accounting is still the bottom line in fat loss. Until the basic laws of thermodynamics change, this will continue to be the case.


Another popular notion is the idea that increasing activity will burn enough extra calories to create a calorie deficit. The problem is, we just don't burn that many calories above our baseline when we exercise. You can get on a computerized stair stepper and exercise until it says you have burned 300 calories. The problem is, this 300 calories includes the calories you burn at rest. A 150 pound man will burn about 100 calories per hour at complete rest, and slightly more when he is up and about. So you really have burned only 150 to 200 calories above your baseline for that entire day. If you reward yourself with a couple of cookies or a Latte, you have completely negated your effort. If we really burned that many extra calories through exertion, we never would have survived as a species. We would have died in the process of hunting and gathering, as the metabolic expense of this activity would have been too high. If we burned calories as fast as the health club treadmill or stepper says we do, we probably could not afford the metabolic expense of shopping and putting up the groceries. But we have bought into the idea of burning off fat through exercise. Instead of exercising to stimulate a desired physical adaptation, many people now exercise as a form of guilt absolution, believing that they can burn off the extra calories they should not have eaten the night before.

What proper exercise can offer in a fat loss effort is two things: 1) increased basal metabolic rate, and 2) discriminant weight loss. Remember, we have established that muscle is metabolically expensive tissue. This metabolic expense is probably why myostatin is present to prevent too much muscle from accumulating. Measurements show that a pound of muscle probably takes 40-50 Calories a day just to stay alive. Some experts think it can be as high as 100 Calories per day (individuals for whom this is true would probably have a higher myostatin expression). If someone were to add 10 pounds of muscle to their body, this would be an extra 500 Calories per day burned. Over the course of a week, that is 3,500 Calories, which is the amount of calories in a pound of fat.

Discriminant weight loss means that any weight loss that occurs is shunted almost entirely toward fat loss. Ken Hutchins once told me to think of the body as a corporation, with several different departments. If the corporation is operating at a budget deficit (calorie deficit), then layoffs will have to occur. If no increased orders are coming in to any given department, layoffs will occur evenly in all departments. Therefore, layoffs will occur in muscle, body fat, bone, connective tissue and nervous tissue. If, however, a large order is placed for extra muscle occurs, then layoffs occur in a different pattern. New muscle has to be brought on, so no layoffs can occur here. The new muscle that is brought on has to be connected to bone by connective tissue. Stronger muscle is now attached to bone, which must also hire on new helpers to bear the strain. All that new muscle can only contract if it is wired-up to new nervous tissue, so new hires have to occur in this department as well. The only department that can take layoffs in this circumstance is the fat department. All of the calorie deficit has to be absorbed by fat loss. In this way you increase your appearance-enhancing tissue, while greatly decreasing your unsightly body fat. By combining proper muscle-stimulating exercise with a reduced calorie diet, you can produce dramatic shape changes.


Dietary Recommendations


One thing that irritates me about many diet books, is that they offer exercise advice which really is nothing more than sweet nothings and conventional wisdom. They feel compelled to recommend exercise, and then feel it necessary to offer some cursory advice on an exercise program.


Since this is a book on exercise, I will endeavor to leave dietary advice to some experts who I believe are the best. All of these books recognize the importance of caloric accounting in fat loss, and offer slightly different ways of acquiring a calorie deficit. My personal favorite is Portion Savvy by Carrie Latt Wiatt. This book trains you to adjust your portion sizes to a level where you can enjoy life-long leanness. It even uses pop-out pictures that you can remove from the book and carry with you. These are actual to-scale photos of food in the correct portion size. When you are out eating, you can actually use the pop-out to trim your meal to the correct serving size. Another excellent book is Dr. Shapiro's Picture Perfect Weight Loss. This book uses visual aids that compare commonly consumed meals with less calorie dense foods. It shows you how much more you can eat when foods that are less calorie dense are chosen. This is an excellent book for making you aware of where hidden calories are lurking. It also gets you in the habit of recognizing foods that will sabotage your program. This book will make you a much better food shopper.

In my opinion, the only person to successfully combine excellent advice on exercise and diet is Ellington Darden, PhD. He has numerous books on fat loss. Some of his best books are A Flat Stomach A.S.A.P., Living Longer Stronger, and Soft Steps to a Hard Body. I have no professional or financial affiliations with any of these authors, I just feel their books are the best diet books currently available, and finding a good diet book without my recommendation might be like finding a needle in a haystack.