Jade Teta ND, CSCS and Keoni Teta ND, LAc., CSCS
Everywhere we go in the fitness world, we hear the same old song-and-dance about calories in vs. calories out. It comes from all corners of the industry from the most respected conditioning coaches, to the celebrity fitness queens, to Joe the personal trainer at the 24hr fitness complex. But have you ever stopped to think if this even makes sense? You exist in a world where food is cheap, tasty, and abundant. You live in a body programmed through the centuries to seek out and eat food above all else. And when you go to your nutritionist, doctor, or personal trainer for advice, they tell you to eat less and move more. To us, this is equivalent to telling someone with an overactive bladder to urinate less and stop using the bathroom. The calorie model is a complete and udder failure in the world of weight loss and we think it is time to just admit it.
Justification of calorie counting
Sometimes it is easier to memorize something than to actually understand it. To truly understand energy consumption in the body, you must first understand thermodynamics or more accurately bioenergetics. The first law of thermodynamics states that energy can neither be created nor destroyed. In other words, if you take in too much energy it will not just disappear, but be stored in a different form, fat. This is the most quoted defense of the calorie model and is often seen as incontrovertible evidence of the truth of the theory. There are two problems with this argument. First, there are other ways energy can be stored. Energy can be stored as carbohydrate (glycogen) or protein (muscle) as well as fat. Given this, would it not be fair to say that some extra calories can be stored as muscle? Next, and more importantly, you cant go around preaching the first law of thermodynamics and forget there is a second law. This second law, called the law of entropy, when combined with the first law generates a much more accurate picture of human metabolism and explains why the calorie model is flawed. The law of entropy essentially says there is no such thing as a 100% efficient engine, and the human engine is no exception. Energy does not simply flow from one form to another but can take on many different forms. In the human body, this other form is heat. While the first law would have you believe any extra calories you eat will be stored as fat, the second law makes it clear that energy transfer is never 100% efficient in living systems. In other words, energy can be lost as heat.
A calorie is not a calorie
To understand how the two laws operate in the real world, lets take a look at the caloric value of a gram of carbohydrates, protein and fats. Carbohydrates and protein are said to each provide 4 calories of energy per gram. Fat contains 9 calories per gram. Based on the first law of thermodynamics we would be forced to believe that no matter what the mixture of calories you eat, if you consume more calories than your body requires you are going to get fat. But this is wrong. It has been shown that each of these types of calories does not have the same metabolic efficiency. In other words, eating carbohydrates vs. protein vs. fat has a very different outcome when they interact with the human engine. Each type of macronurient (protein, fat, carbohydrate) when digested will burn in the body. Some of the energy will be directly captured and some of the energy will be lost as heat. This is known as the thermic effect of food. Protein is said to have a thermic effect of around 30%, while carbohydrates are 10%, and fat is 3%. This means for every gram of protein a full third of the calories will be lost as heat meaning each gram of protein actually provides 2.8 calories not 4 (4 X .70 = 2.8). For carbohydrates the rate is smaller, 3.6 calories (4 X .90 = 3.6). And for fat, the thermic effect is negligible, 8.73 calories (9 X .97 = 8.73). This illustrates that a calorie of protein is not the same as a calorie of carbohydrate or fat. This illustrates that the ratio of protein, carbohydrates, and fat does indeed make a difference and is not simply about total caloric intake.
A recent study in the May 14th 2009 addition of Nutrition and Metabolism showed the above effect does occur in humans. In this study, three groups were analyzed. Each group was given the same amount of calories but a different ratio of protein to carbohydrate to fat. The group that had the highest protein intake relative to carbohydrates lost the most fat, retained the most muscle, ended the study with a higher resting metabolic rate, lost more inches around the waist, and experienced positive reductions in cardiovascular markers of health. The authors of the study concluded “These findings suggest that replacing carbohydrate with protein can be an effective strategy to improve body composition and reduce cardiovascular disease markers.”
Exercise and calories
The calorie model provides little help with exercise as well. Up until recently experts thought the best way to lose fat was to exercise in an aerobic zone for 20 to 60 minutes. The rationale was that more fat was burned at these lower intensities and would aid fat loss. Unfortunately, several negative studies on aerobic exercises ability to help weight loss along with many positive studies on more anaerobic exercises (sprint training, interval training, resistance exercise), have created confusion about exercise, calories and weight loss. This is because like the example of protein with nutrition, certain types of exercise burn calories in different ways. During lower intensity exercises like walking, running, or biking researchers can easily measure respiratory exchanges and predict with accuracy how many calories are burned. But when exercise intensity moves into the anaerobic zone, the heat effect we saw with nutrition kicks with exercise causing calorie consumption to be drastically underestimated. A 2005 research paper by Dr. Christopher Scott (Journal of the International Society of Spots Nutrition, Vol. 2 #2), showed that anaerobic exercise burns 30% more energy then aerobic exercise in the form of heat that cannot be accounted for by traditional caloric calculations. Numbers like this should make all experts uncomfortable about the legitimacy of standard calorie counting methods in exercise. These numbers alone would account for the many recent studies and overwhelming clinical experience of personal trainers and conditioning coaches who advocate more unconventional anaerobic training in their programs.
Hormones, enzymes, and calories
Given the outcome of the above studies, it would make sense for nutrition and exercise experts to discard the old “calories-in-versus-calories-out-mantra” and replace it with something like “more quality calories eaten means more quality weight lost”. In other words, if you are worried about losing fat, which is different then weight loss, you should pay attention to the types of food and exercise you do rather than just the amount. This idea of quality over quantity is another major drawback of the calorie model. Hormones, and other signaling molecules, are what run your metabolic engine. They switch fat-burning enzymes on or off and force them to run faster or slower. Cutting calories does not necessarily speed fat-burning enzymes up, but often can slow them down. A February 2009 study (vol 4, #1 of the journal PLOS One) showed that low calorie diets significantly reduce metabolic rate and create a progressive resistance to further weight loss after each month. The researchers in this study showed this effect is due to a loss in muscle mass, but that 6% of the decline is related to some other metabolic process. This other metabolic process is likely related to hormones. Thyroid hormone, among others, is known to decline with energy reduction and impedes results on low calorie diets.
Perhaps the biggest impact of hormones on body composition come from the neurohormones and hunger hormones. Many people perceive willpower as something separate from biochemistry, but there is a reason people are unable to stay on low calorie programs. The body is hardwired through neurohormones and hunger hormones to seek out and eat food whenever it is available. Calorie restricted programs force these mechanisms into overdrive making people more likely to overeat and less likely to want to exercise. It is almost impossible to stay on a program of calorie reduction for this reason. Once again the quality of calories eaten and the type of exercise done can dramatically alter the negative drive for food. Short intense exercise as well as increased protein and fiber are able to reduce appetite and balance brain neurohormones allowing greater adherence to programs that seek to alter eating and exercise habits.
Final thoughts
The calorie model has been a complete failure in combating obesity and helping people make meaningful lasting change in their physiques. The way the body regulates its energy is far more complex than the simple calories in verse calories out model. Manipulating the quality of dietary and exercise practices is far more useful than a focus on quantity. A chicken breast and a doughnut may have the same amount of calories, but they create a very different outcome for your metabolism. Paying closer attention to what goes in your mouth as well as the type of exercise you do will pay greater fitness dividends than counting the number of calories you consumed in a day.