Good Calories, Bad Calories

The institutionalized vigilance, “this unending exchange of critical judgment,” is nowhere to be found in the study of nutrition, chronic disease, and obesity, and it hasn’t been for decades. For this reason, it is difficult to use the term “scientist” to describe those individuals who work in these disciplines, and, indeed, I have actively avoided doing so in this book. It’s simply debatable, at best, whether what these individuals have practiced for the past fifty years, and whether the culture they have created, as a result, can reasonably be described as science, as most working scientists or philosophers of science would typically characterize it. Individuals in these disciplines think of themselves as scientists; they use the terminology of science in their work, and they certainly borrow the authority of science to communicate their beliefs to the general public, but “the results of their enterprise,” as Thomas Kuhn, author of The Structure of Scientific Revolutions, might have put it, “do not add up to science as we know it.”

Though the reasons for this situation are understandable, they offer scant grounds for optimism. Individuals who pursue research in this confluence of nutrition, obesity, and chronic disease are typically motivated by the desire to conserve our health and prevent disease. This is an admirable goal, and it undeniably requires reliable knowledge to achieve, but it cannot be accomplished by allowing the goal to compromise the means, and this is what has happened. Practical considerations of what is too loosely defined as the “public health” have consistently been allowed to take precedence over the dispassionate, critical evaluation of evidence and the rigorous and meticulous experimentation that are required to establish reliable knowledge. The urge to simplify a complex scientific situation so that physicians can apply it and their patients and the public embrace it has taken precedence over the scientific obligation of presenting the evidence with relentless honesty. The result is an enormous enterprise dedicated in theory to determining the relationship between diet, obesity, and disease, while dedicated in practice to convincing everyone involved, and the lay public, most of all, that the answers are already known and always have been—an enterprise, in other words, that purports to be a science and yet functions like a religion.

The essence of the conflict between science and nutrition is time. Once we decide that science is a better guide to a healthy diet than whatever our parents might have taught us (or our grandparents might have taught our parents), then the sooner we get reliable guidance the better off we are. The existence of uncertainty and competing hypotheses, however, does not change the fact that we all have to eat and we have to feed our children. So what do we do?

There are two common responses to this question, as there will be to the arguments made in this book. One response is to take into account the uncertainties about the health effects of fats and carbohydrates and then suggest that we simply eat in moderation. This in turn implies eating a balanced diet in moderation. “Perhaps our most sensible public health recommendation should be moderation in all things, and moderation in that,” as the University of Michigan professor of public health Marshall Becker suggested back in 1987. But some of us do eat with admirable restraint of the four major food groups and yet are obese or overweight anyway, and presumably have an increased risk of other chronic diseases because of it; some of us are suitably lean, eat balanced diets in moderation, and exercise regularly and yet are insulin-resistant and maybe even diabetic.

The more optimistic response is a compromise position: to take virtually every reasonable hypothesis from the past fifty years that can coexist with the saturated-fat/cholesterol hypothesis of heart disease and fold them all into one seemingly reasonable diet that might do us good and probably won’t do harm. Thus, the current conception of a healthy diet is one that minimizes salt content and maximizes fiber; has plenty of good fats (monounsaturated and omega-three polyunsaturated fats) and minimal bad fats (saturated fats and trans fats); has plenty of olive oil and fish, and little red meat, butter, lard, and dairy products. When meat is consumed, it’s lean, which keeps saturated-fat content down and reduces energy density and thus, supposedly, calories. Dairy is low-fat or no-fat. The diet has plenty of nuts and legumes and good carbohydrates, which are those with copious vitamins, minerals, antioxidants, and fiber (vegetables, fruits, and unrefined grains), but few bad carbohydrates, which are energy-dense and thus contribute to obesity (highly refined carbohydrates and sugars).

It may be true that such a diet is uniquely healthy—but we have no idea if that’s really so. The diet has the advantage of being politically correct; it can be recommended without fear of ostracism from the medical community. Whether it is healthier, however, than, say, a meat diet of 70–80 percent fat calories and absent carbohydrates almost entirely, as Stefansson suggested in the 1920s, or any diet of animal products (meat, fish, fowl, eggs, and cheese) and green vegetables but absent entirely starches, sugar, and flour or even sugar alone, is still anybody’s guess. And whether such a diet would prevent us from fattening or reverse obesity, or do it better than a mostly meat diet, has also never been tested. If it doesn’t, then it’s probably not the healthiest diet, because excessive fat accumulation is certainly associated with increased risk of chronic disease.

I have spent much of the last fifteen years reporting and writing about issues of public health, nutrition, and diet. I have spent five years on the research for and writing of this book alone. To a great extent, the conclusions I’ve reached are as much a product of the age we live in as they are my own skeptical inquiry. Just ten years ago, the research for this book would have taken the better part of a lifetime. It was only with the development of the Internet, of search engines and the comprehensive databases of the Library of Medicine, the Institute for Scientific Information, research libraries, and secondhand-book stores worldwide now accessible online that I was able, with reasonable facility, to locate and procure virtually any written source, whether published a century ago or last week, and to track down and contact clinical investigators and public-health officials, even those long retired.

Throughout this research, I tried to follow the facts wherever they led. In writing the book, I have tried to let the science and the evidence speak for themselves. When I began my research, I had no idea that I would come to believe that obesity is not caused by eating too much, or that exercise is not a means of prevention. Nor did I believe that diseases such as cancer and Alzheimer’s could possibly be caused by the consumption of refined carbohydrates and sugars. I had no idea that I would find the quality of the research on nutrition, obesity, and chronic disease to be so inadequate; that so much of the conventional wisdom would be founded on so little substantial evidence; and that, once it was, the researchers and the public-health authorities who funded the research would no longer see any reason to challenge this conventional wisdom and so to test its validity.

As I emerge from this research, though, certain conclusions seem inescapable to me, based on the existing knowledge:

1. Dietary fat, whether saturated or not, is not a cause of obesity, heart disease, or any other chronic disease of civilization.

2. The problem is the carbohydrates in the diet, their effect on insulin secretion, and thus the hormonal regulation of homeostasis—the entire harmonic ensemble of the human body. The more easily digestible and refined the carbohydrates, the greater the effect on our health, weight, and well-being.

3. Sugars—sucrose and high-fructose corn syrup specifically—are particularly harmful, probably because the combination of fructose and glucose simultaneously elevates insulin levels while overloading the liver with carbohydrates.

4. Through their direct effect on insulin and blood sugar, refined carbohydrates, starches, and sugars are the dietary cause of coronary heart disease and diabetes. They are the most likely dietary causes of cancer, Alzheimer’s disease, and the other chronic diseases of civilization.

5. Obesity is a disorder of excess fat accumulation, not overeating, and not sedentary behavior.

6. Consuming excess calories does not cause us to grow fatter, any more than it