‘Obesity is caused by eating too many calories and not enough exercise.’
This statement is so widely accepted as true that most are shocked to learn that it has ever been debated. It seems on the surface to be a restatement of a fundamental law of the physical sciences, known as The First Law Of Thermodynamics, or Conservation of Energy. As it relates to obesity, this law means that the amount of calories (energy) a person stores in the form of fat has to equal the amount they eat less the amount they burn. In other words, in a closed system, energy is not created out of nothing and it doesn’t just disappear. Energy is conserved.
But there is an alternative explanation for obesity that doesn’t violate The First Law Of Thermodynamics, and it has a very long history. In fact, The Alternative Hypothesis (now routinely capitalized) was taken so seriously at one time that it became the majority view of the nutritional science community in Germany prior to the second World War. The debate in our country was silenced in the 1970s, when the U.S. federal government adopted a public health policy that included dietary recommendations. Congress picked a side, and advocates of The Alternative Hypothesis soon found themselves marginalized, unable to get their research funded.
In recent years, an epidemic of obesity and a growing list of research findings have simultaneously discredited the conventional view and lent strong support to The Alternative Hypothesis. At the same time there has been a growing group of journalists, scientists, physicians, and lay people calling for the debate to be reopened and for a reassessment of public health funding. This is the subject of two books by author Gary Taubes, one of the leaders of cause. Good Calories, Bad Calories (2008), is a densely written tome with 166 pages of footnotes. It is targeted at scientists and medical professionals. Why We Get Fat: And What to Do About It (2010), is a much shorter and more accessible treatment aimed at lay people. I strongly recommend both of these books.
The Alternative Hypothesis says that the amount of fat that your body stores is regulated by a system that, when operating properly, keeps body weight balanced for optimal health. It works by controlling your hunger and the energy that you have available to burn calories. If you become very active and burn a lot of calories, then the system adjusts your hunger so that you take in more calories to keep everything in a proper balance. Conversely, if you run a calorie deficit, the system saps your available energy so that you burn as few calories as possible until the balance is restored. Obesity is simply a breakdown of this system, and overeating and sedentary behavior are symptoms of the illness, but they are not the cause.
Now consider the difference between these two statements:
- For obesity to occur, more calories must be consumed than are burned.
- Obesity is caused by consuming more calories than are burned.
The Alternative Hypothesis accuses the conventional view of making a logical fallacy known as Cum Hoc Ergo Propter Hoc, or mistaking correlation for causality. An example of this fallacy would be the observation that the rooster crows every time the sun comes up, and therefore concluding that the rooster’s crow causes the sun to come up. In future posts, you’ll be reading a lot about this logical fallacy because it is at the heart of most of the misinformation in nutrition science. The Alternative Hypothesis is in complete agreement with statement 1 (a restatement of The First Law Of Thermodynamics) but it says that statement 2 is totally false.
The idea that body fat is self-regulating is easy to wrap your mind around when you consider the multitude of other systems in human biology that work exactly the same way. Every second of your survival requires maintaining a host of systems within a very limited range of parameters. These include your body temperature, water content, blood salt concentration, blood pressure, blood glucose levels, blood oxygen levels, blood iron levels, blood calcium levels, blood potassium levels, blood volume, extracellular fluid levels, and on and on and on. The ability of an animal to regulate the internal environment of its body, the milieu intérieur, as pioneering physiologist Claude Bernard called it is known as homeostasis (Greek for “standing still”).
You are familiar with many other homeostasis regulators in your body by the names of the diseases that result when the system fails. Glaucoma results when the intraocular pressure system fails to maintain homeostasis. Epileptic seizures occur when homeostasis of the neural activity of the brain is not maintained. Gout is caused by a failure of the homeostasis regulator for uric acid levels in the blood.
So when someone suggests that obesity (and perhaps anorexia) are caused by the failure of a homeostasis regulator for body fat storage, it is not an outrageous supposition. If such a system didn’t exist, you’d have to wonder why not. Why do we have to fight hunger to stay lean and healthy when all these other systems maintain homeostasis automatically?
Now lets take this one step further and say that excess carbohydrates in the diet is the stressor that ultimately causes the breakdown of body fat regulation known as obesity. [Note: I am referring to the subset of carbohydrates that are digestible by humans – sugars and starches – and not the complex undigestible ones known as dietary fiber.]
Gary Taubes spends a considerable amount of time in his book Good Calories, Bad Calories discussing the exact mechanism for fat regulation and how it breaks down. The discussion focuses on the hormone insulin. If you are into that, read his book. I am going to steer clear of this topic. Taubes could be mistaken about some minor aspect of the biochemistry but still be right about the general truth. And I have no qualifications to participate in a debate about biochemistry.
When the system break down occurs, the level of fat that your body stores (homeostasis) shifts. How much is a function of the amount of carbohydrates in your diet, your genetics, and the amount of time your system is stressed. Some individuals might become obese as babies, others upon middle age, and others not at all.
This model for obesity predicts several commonly observed features of the disease that conventional wisdom does a poor job explaining. For example, throughout my life, I have known people who seemed to be able to eat almost anything and they did not gain weight. I have also known people who never showed a trace of obesity and then over a short period of time they became obese. The idea that these people just one day let themselves go begs the question: what changed?
The Alternative Hypotheses explains why dieting generally doesn’t work. If you starve yourself by restricting calories and cause short term weight loss but fail to address the underlying fat regulation disorder, then when you go back to a normal eating pattern, you should quickly return to the weight you were at when you started. This “Oprah” effect is common. It also describes my personal experience with weight loss.
Perhaps you are thinking, “But I know people who have lost weight by restricted calorie dieting and kept it off. If the Alternative Hypothesis is right, how can that happen?” If you put yourself in a calorie deficit by starving yourself, you are at the same time cutting the carbohydrates that stress your fat regulation system. Starvation is a low carb diet (and unnecessarily a low fat and low protein diet.) If someone loses a lot of weight dieting, you can bet that their total carb intake was cut dramatically. And if they are keeping the weight off, then you can bet that their total carb consumption is nowhere close to its original level. A shocker would be to find people who have lost weight while boosting their total carbohydrate consumption. Good luck finding examples of that.
Now that we are on the subject of carbohydrates, it is important to understand a basic rule regarding macronutrients. There are three macronutrients: protein, carbohydrates, and fat. Each is a fuel source for human beings, and each are handled differently by the body. For the sake of this discussion it is important to understand that when people change their diet, it is a well known fact that they generally keep the percentage of total calories from protein at a constant level. (In fact, the amount of protein your body can handle in your diet is limited. If you ate nothing but protein, you would die from a condition known as rabbit starvation.) So when people cut the percentage of total calories from carbohydrates, they boost their fat consumption proportionately. Conversely, cutting fat in your diet raises the percentage of calories from carbs proportionately. The recommendation to ‘eat less fat in your diet’ can be restated as ‘eat more carbs.’ The recommendation to ‘eat fewer carbs’ can be restated as ‘eat more fat.’
So now you can see the crux of the debate. Conventional dietary wisdom says that since fat is the densest source of calories in our diet, it should be eaten very sparingly. Furthermore, there is something called the lipid hypothesis (which will be the subject of a later post) that says heart disease is caused by elevated blood cholesterol levels. And since eating fat is generally believed to raise cholesterol, conventional wisdom says a low fat diet should reduce your risk of heart disease and lead to weight loss. The Alternative Hypothesis says that the opposite is true.
When Congress sided with the conventional explanation for obesity, they also made the recommendation that people eat a low fat diet. Advocates of The Alternative Hypothesis expected that these recommendations would lead to an epidemic of obesity in America, and that is exactly what has happened. (Documentaries like “Super Size Me,” from 2004, who blame the obesity epidemic on companies like McDonald’s for selling super-sized portions, are yet another example of the Cum Hoc Ergo Propter Hoc fallacy.)
Now, there is a stack of respected research demonstrating that low carb/high fat diets result in weight loss and a lowering of risk factors for heart disease. Diets that are highest in carbohydrates (and lowest in fat) are the least successful, often demonstrating weight gain. And yet physicians are largely ignoring these findings. This wouldn’t be so difficult if the dietary recommendations weren’t directly the opposite of conventional wisdom.
The Alternative Hypothesis also leads you to think of obesity as primarily a physical malady, rather than a psychological disorder. This not as controversial a thing to say as it once was because the problem is so prevalent that obesity has a lot of defenders. The same cannot be said for anorexia nervosa. The idea that anorexia might be fundamentally caused by the breakdown of the body’s weight regulation system is heretical at present, but it sure helps explain the low rate of recovery from that disease.
The Alternative Hypothesis has far reaching social and economic implications. And it should be of interest to everyone, regardless of whether they struggle with obesity or not. The Alternative Hypothesis means that eating high carb foods is willingly subjecting yourself to a risk factor for disease that is probably much worse for your health, in the long run, than cigarettes. It will surely take some time for this truth to become common knowledge. But when it does, the societal attitude shift will be even more dramatic than the shift that has taken place since cigarettes were being advertised in the Journal of the American Medical Association – yes I said the Journal of the AMA.