Good Calories, Bad Calories

Whether the addiction is in the brain or the body or both, the idea that sugar and other easily digestible carbohydrates are addictive also implies that the addiction can be overcome with sufficient time, effort, and motivation, which is not the case with hunger itself (except perhaps in the chronic condition of anorexia). Avoiding carbohydrates will lower insulin levels even in the obese, and so ameliorate the hyperinsulinemia that causes the carbohydrate craving itself. “After a year to eighteen months, the appetite is normalized and the craving for sweets is lost,” said James Sidbury, Jr., about the effects on children of his carbohydrate-restricted diet. “This change can often be identified within a specific one to two week period by the individual.”

If the more easily digestible carbohydrates are indeed addictive, this changes the terms of all discussions about the efficacy of carbohydrate-restricted diets. That someone might find living without starches, flour, and sugar to be difficult, and that there might be physical symptoms accompanying the withdrawal process, does not speak to the possibility that they might be healthier and thinner for the effort. No one would argue that quitting smoking (or any other addictive drug) is not salutary, even though ex-smokers invariably miss their cigarettes, and many will ultimately return to smoking, the addiction eventually getting the better of them. The same may be true for these carbohydrates.

It also makes us question the admonitions that carbohydrate restriction cannot “generally be used safely,” as Theodore Van Itallie wrote in 1979, because it has “potential side effects,” including “weakness, apathy, fatigue, nausea, vomiting, dehydration, postural hypotension, and occasional exacerbation of preexisting gout.” The important clinical question is whether these are short-term effects of carbohydrate withdrawal, or chronic effects that might offset the benefits of weight loss. The same is true for the occasional elevation of cholesterol that will occur with fat loss—a condition known as transient hypercholesterolemia—and that is a consequence of the fact that we store cholesterol along with fat in our fat cells. When fatty acids are mobilized, the cholesterol is released as well, and thus serum levels of cholesterol can spike. The existing evidence suggests that this effect will vanish with successful weight loss, regardless of the saturated-fat content of the diet. Nonetheless, it’s often cited as another reason to avoid carbohydrate-restricted diets and to withdraw a patient immediately from the diet should such a thing be observed, under the mistaken impression that this is a chronic effect of a relatively fat-rich diet.

In 1963, when Robert Kemp discussed his clinical experience with carbohydrate-restricted diets and the apparent problem of carbohydrate addiction, he made the point that the necessary step was to establish beyond reasonable doubt whether carbohydrates indeed were the cause of obesity and overweight. By doing so, we could then make informed decisions about the risks and benefits of our cravings. Many former cigarette smokers would likely still be smoking today without the certain knowledge that tobacco causes lung cancer. “At least half of our patients, win or lose, cannot be persuaded that they must permanently alter their eating habits to save their lives,” Kemp wrote. “This is undoubtedly a battle for the mind where unfortunately the patient is completely unsettled by the confusion of advice offered from both professional and lay sources.” This statement is still true today. Carbohydrate-restricted diets will always be tempting, if for no other reason than their efficacy at inducing weight loss. But to make a permanent change in diet requires the confidence that we will be healthier for doing so. For that, we need the support of physicians, nutritionists, and the public-health authorities, and we need advice that is based on rigorous science, not century-old preconceptions about the penalties of gluttony and sloth.

EPILOGUE

The community of science thus provides for the social validation of scientific work. In this respect, it amplifies that famous opening line of Aristotle’s Metaphysics: “All men by nature desire to know.” Perhaps, but men of science by culture desire to know that what they know is really so.

ROBERT MERTON, Behavior Patterns of Scientists, 1968

The first principle is that you must not fool yourself—and you are the easiest person to fool.

RICHARD FEYNMAN, in his Commencement Address at Caltech, 1974