I am comfortable explaining why I think CrossFit is an excellent training regime, but I try not to do it in a negative way by criticising other regimes. After all, if you look around and see the amount of obesity in our society it is rather silly to be overly critical of someone else’s exercise regime. If people are out there moving and trying to improve their functional ability then they are far ahead of most people in our society. And in truth I think a lot of people doing really good things for their health, but could perhaps do better, have been only given part of the story. So it is even crazier to be critical when they haven’t been given the correct information. There are many examples of where CrossFit is a superior training regime but for this article I will focus on quantity of exercise. I think too many in the health and fitness industry focus on quantity of exercise (and food) and pay little attention to quality. One obvious example is weight control, where most “authorities” in the field have used the first law of thermodynamics (conservation of energy) and the energy balance equation (EBE) to promote low-fat diets and long steady endurance workouts. The EBE quite simply states: Change in energy stores = Energy intake – Energy expenditure This equation must be correct in the simplest sense due to the laws of physics. However, despite the apparent simplicity, the interplay between the variables in this equation is complex. Most weight loss programs have simply (and wrongly) treated energy intake and energy expenditure as two independent variables. Therefore, the message conveyed is that individuals who want to lose weight only need focus on decreasing caloric intake, increasing energy expenditure, or a combination of the two. This might appear reasonable, and, since a gram of fat is nine calories, and protein and carbohydrate are approximately four calories per gram, this approach would seem to support the notion that a low-fat diet is best for weight loss. Similarly, if I can burn hundreds more calories by going for an hour-long run versus doing some shorter intense workout, then it is argued that slow and steady workouts must be better for weight loss. Perhaps because of the simplicity of this logic, these notions persist, despite a mountain of evidence showing that low-fat diets do not work very well, if at all, for most individuals. There is also a growing amount of research showing that higher intensity workouts are better for fat loss compared to working out slow and steady. A further, simplistic interpretation of the EBE is that people in our society who are overweight and obese must be eating too much and not exercising enough. While this may be true for many, a number of studies have shown that at least some overweight individuals eat the same number of calories, or fewer, than lean individuals. Understanding why they stay overweight is neither rocket science nor a violation of the law of energy conservation. The food we eat elicits hormonal responses, which determine how energy is stored in the body—that is, in the form of body fat. Basically, energy intake is not independent of energy expenditure, and the type of calories you eat does affect your energy output. Energy intake and energy expenditure are dependent variables. Sugar, high-fructose corn syrup, and easily digestible carbohydrates drive an insulin response, and insulin drives fat storage. Many excellent researchers in this field argue that dietary fat—or even calorie quantity—is not the main culprit at all. Another way to demonstrate that the EBE is controlled by hormonal response is to look at growing children. Do children grow because they eat too much? No, children grow due to the influence of hormones. They do not think, “I better eat a lot because I am growing.” Hormones stimulate their appetite and dictate how this “excess” of nutrients is stored. When children eat and exercise properly, the growth will be primarily vertical (we hope) and include muscle, bone, organs as well as some adipose tissue. For an adult eating a diet high in easily digestible carbohydrates, the hormonal response will cause growth in the form of fat accumulation. Studies have shown that individuals on low-calorie weight-loss diets tolerate high-fat, high-protein, low-carbohydrate diets better than low-fat diets. Despite low overall calorie intake, they do not report feeling hungry all the time and their metabolism does not slow down in an attempt to maintain fat stores. These kinds of diets were commonly prescribed up until World War II; diets such as Atkins diet (a low carbohydrate diet) would not have been considered “fad diets” in the nineteenth and first half of the twentieth centuries. So there is strong evidence that, when you are looking at the energy intake variable in the EBE, a calorie is not just a calorie. All calories are not equal; the quality of those calories (the type of nutrient and overall nutrient balance) is very important. Restricting caloric intake but continuing to eat much of it in the form of high-glycemic foods will make your body fight to maintain its fat stores and will lower your metabolism. Put in point form: • Your body secretes the hormone, insulin, in response to a rise in blood sugar. • Insulin drives the body to store the excess blood sugar as fat. • Insulin inhibits your body’s ability to mobilize fat out of adipose tissue and burn it as a fuel. Therefore, chronically high insulin levels work against fat loss. • Simple carbohydrates (high-fructose corn syrup, sugar, and white flour, for example) increase blood sugar levels the most, and increase insulin levels. • Very high total-carbohydrate quantities in diets also increase insulin levels. • Chronically elevated levels of insulin is a factor for metabolic syndrome, which includes obesity, Type 2 diabetes, high blood pressure, and more. There is no well-researched evidence that contradicts this information. What role does exercise play in weight control? In a parallel manner to my brief discussion on food intake, understanding the relationship between exercise and weight control lies in understanding the body’s hormonal response to exercise. Most weight loss programs have had subjects doing exercise like 20–60 minutes of steady-state low-power activities, such as walking, jogging, and cycling. These modes of exercise are less than ideal for improving aerobic conditioning and ineffective at stimulating significant production of testosterone, human growth hormone, and the other hormones involved in optimal health and body composition. In fact, chronic low power-output endurance exercise has been shown to lower testosterone levels in male subjects. Just as the “calorie is a calorie” logic is flawed with regard to energy intake, anaerobic/power athletes the world over have shown that the prevailing logic on the energy expenditure side of the equation is equally as flawed. In other words, stating that “a calorie burned is just a calorie burned” is too simplistic. Just as the type of calorie you are eating makes a difference, the type of exercise you are doing makes a difference. Tremblay and Bouchard (1994) reported that a group of subjects doing bike interval work (series of sprints) lost more body fat than another group doing steady-state cycling. The researchers controlled the work so that the total external work done (measured as calories expended) per session was the same for both groups. The sprint-interval group did the same amount of external work and yet lost more body fat, which correlates with the notion that high power outputs elicit different (read, “better”) hormonal responses than low-power steady-state ones. So not only is interval training better than slow and steady at developing aerobic capacity, there is no doubt that interval work is also very effective for fat loss. If you have friends reluctant to start CrossFit due the intensity, there is some evidence that simply breaking up your workout can be beneficial. Goto, et. al. (2011) did a study where allowing time for rest periods burned more fat than exercising for one continuous session. The authors concluded, “These results suggest that the repetition of 10-min of moderate exercise can contribute to greater exercise-induced fat oxidation compared with a single 30-min bout of continuous exercise.” My point in mentioning this article is again to emphasize that despite doing the same amount of work, the subjects’ body composition response was different if the work was broken up. If the same exercise can elicit different responses just think how much different rope climbs and cleans are to a long slow steady state run. Try this little experiment; complete 50 step-ups onto a 20” or 24’ box as fast as you can. Go hard and try to get a good time. Later (or the next day), to negate the effects of fatigue, try to perform 50 two-footed jumps onto the same box in the same time. Which felt harder? Which fatigued you more? If you pushed hard on the step-ups, you likely were not able to complete the box jumps in the same time. If you can, try it again another time with 100 step-ups versus 100 box jumps. The difference in times will likely be even more pronounced, with the step-ups being done in considerably less time. What is my point? Assuming you didn’t jump higher than you needed to, the amount of external work done is the same for the step-up and box jump, since you raise your body weight the same distance. If you completed the 50 steps and 50 jumps in the same amount of time, the average power (work/time) would also be the same. However, the peak power involved in each activity is quite different. This is because the step-up is a gradual application of force—I raise my leg, place it on the box, and push up in a controlled manner until I am standing erect—whereas the jump is a short- duration explosive effort that accelerates the body in a shorter time. I have calculated that a 180-pound athlete would produce an average power of roughly 1,500 Watts during a step-up onto a 24-inch box. The peak power in the step-up motion is unlikely to be more than 2,500 Watts, and probably less. In contrast, the peak power of a jump onto the box would be approximately 5,400 Watts (around two to three times the peak power output of the step-up). Clearly, if you are doing the same amount of work in two comparable but different exercises and yet find one type of exercise more fatiguing, and if you do the same amount of work and yet lose more subcutaneous body fat with one type of exercise, then something else is going on other than a simple calculation of calories expended. One factor is that we are measuring external work (how far you move your body and in what time frame). However, the actual total energy (internal and external) cost of acceleration (overcoming inertia) is very high. If you drive a car and accelerate toward every stop sign, brake, and then accelerate away again at a high rate, your fuel consumption will be high. The car weighs the same, and if you drive 20 miles at a steady pace or do it in a series of accelerations and decelerations (braking), you have still done the same amount of total external work, but you will have used significantly more fuel. In athletic performance, as well, acceleration requires a huge effort and use of resources (energy). And overcoming inertia (accelerating, lifting, resisting, and changing direction) is a key factor in athletic performance. Olympic lifts and maximal sprints use an incredibly high number of muscle fibres in the explosive effort to produce high accelerations. The hormonal response to such activities is profound. Although squats and deadlifts are “slow” lifts, the sheer weight being lifted also means they are very taxing lifts that will stimulate positive hormonal responses. To say that a 500-pound deadlift is a low-power lift is meaningful only in comparison to something like a maximal clean and jerk. Compared with distance running, heavy deadlifts require massive power output as well as total work. The endocrine (hormonal) response to exercise is vitally important. For example, hormonal response to high-power activities includes increased levels of testosterone, insulin-like growth factor, human growth hormone, and many others. Intense work also causes more cellular damage. On the cellular level, exercise is a stressor—a debilitating process that forces the body to rebuild tissue and strengthen—and there are important hormones involved in this rebuilding process. Your metabolism stays elevated for much longer after a high power activity, due to the action of adrenal gland hormones (such as epinephrine and norepinephrine), as compared with a low power workout. This factor is often overlooked in terms of the energy expended in an exercise session. I am not saying that quantity of exercise is not a factor at all; it is, just as the quantity of calories eaten is still relevant. It is actually very hard to go very intense every day so some endurance days are a good thing to include in your overall fitness regime. But high intensity, across all metabolic pathways, using large percentages of body musculature, are key factors in the efficacy of high intensity activities with respect to body composition and weight control. The adaptation and hormonal response to performing only long, slow, low-powered aerobic work is less effective in driving a healthy hormonal response and a truly healthy body composition—one that includes adequate musculature in all regions of the body, good bone and connective tissue density, and healthy body fat levels. In summary, there is a crucial flaw in the way many doctors, health counsellors, and researchers have been viewing the energy balance equation and its application to weight loss. By regarding energy in and energy out as independent variables, they have ignored the large quantity of research on both humans and animal models that shows the importance of quality as well as quantity—the vital importance of the type of calories consumed. Low fat diets are not the answer. Similarly, many who prescribe exercise for weight loss and health improvement fail to understand the importance of how the energy is expended. The focus is almost always just on quantity. But, in reality, just as for calories consumed, the quality of the exercise performed is as important as the quantity of calories expended. This article is about one beneficial aspect of CrossFit programming, namely that the quality of the programming via functional multi-joint exercises performed across broad time domains and its relationship to body composition. There are of course many more benefits I will discuss over the next few months.