Saturday, December 03, 2011

Nutrition and the Argument from Uncertainty

The fallacy of the argument from uncertainty, or at least one form of it, might also be called the “it’s better to be safe than sorry” argument. For example, the European Union among other inanities recently ruled that children under eight must be supervised while blowing up a balloon, lest the children swallow or choke on part or all of the dangerous inflatable. How likely is this to occur? “Well, we don’t really know for sure,” the reasoning apparently goes. “We can’t be certain, so it’s better to be safe than sorry. An adult must be present.”

The problem with this reasoning is that it is asking opponents to prove a negative. “The balloon might cause choking. Prove that it won’t.” In logic proving a negative cannot be done; the burden of proof is on the one who makes the positive assertion. All that can be said accurately here is that the probability of choking is minuscule and parents must choose their own levels of risk tolerance. When pressure groups and their legislators tell us what to do, our freedoms and possibly our health become endangered.

This last is meticulously demonstrated in the exhaustive investigations of science writer Gary Taubes. In his two latest books, Good Calories, Bad Calories and Why We Get Fat, Taubes reviews over one hundred years of research on the causes of several diseases of civilization, especially heart disease, obesity, and diabetes. His finding is that not only is the consensus of the past thirty to forty years wrong, but that it also was generated and is today still maintained by the argument from uncertainty (my terminology, not his).

The litany of contemporary nutrition says that we should eat a high carbohydrate, low fat—low saturated fat—diet in order to maintain our heart health, remain trim, and fend off diabetes. If overweight, we should of course exercise and cut back on the calories. Taubes found little sound evidence in the scientific literature to support these claims and indeed uncovered a wisdom that was conventional for over a hundred years, until after World War II, that said good health, including trim weight, is achieved by eating a low carbohydrate, high meat, fish, and fowl diet. That is, cut out the sugars and starches and eat as much of the rest as you want. Exercise? It makes us hungry, something from the foggy distant past that our mothers and grandmothers used to say; it does not cause weight loss. Cholesterol and saturated fat? No causal relation to heart disease. Go low carb for all three diseases.

What gives? Are today’s nutritionists lying? No, just “better to be safe than sorry,” so they seem to be saying. During the 1950s and ‘60s, the more rigorous scientific researchers said that data on fat and cholesterol in relation to heart disease were inconclusive, in particular the data of the Seven Countries Study, a project notably omitting France and other countries that would have contradicted the study’s findings. This study, the rigorous researchers said, was at most associational, not causal.

The promoters of the Seven Countries Study, however, said that lives were at stake. We can’t wait for “final scientific proof” (Taubes, p. 23). We must inform the public and have them change their diets. This attitude partnered with the ‘60s hostility to McDonalds and other high-fat fast food diets and culminated in the McGovern report of 1977 that made the litany virtually gospel. In the meantime, well-controlled experiments, right up to the present, continued and still continue to disconfirm the creed. Selection bias, the omission of anomalous data, is a term Taubes uses to help explain the championing of the litany.

In the course of his investigations, Taubes most importantly has liberated obese people from the tyranny of the “gluttony and sloth” argument. “You’re overweight because you eat too much and exercise too little.” Implication? Weakness of the will, bad character. Taubes and the more rigorous researchers? Clearly there is a genetic component to growing wide, just as there is a genetic component to growing tall. Causation indeed likely runs in the opposite direction. That is, we are not necessarily fat because we overeat and underexercise. Rather, we eat more because we are growing and become sedentary because we are fat.

The mechanism of obesity, writes Taubes (pp. 118-21), operates through the hormone insulin. The more carbohydrates we eat, the more insulin our bodies secrete, the more fat—for obese people, at any rate—is taken out of our bloodstream and stored in our fat cells. “Insulin,” as Taubes puts it, “works to make us fatter.”

Coercion in the public schools to make children eat “right” or less has become common, just as the European Union is now making sure children are not unduly exposed to those allegedly dangerous inflatables. Aside from the issue that governments have no right to tell us what or how much to eat, or how we should micromanage our children, how fallacy-proof is the scientific evidence that has led to these policies and near dogma about health and safety? How long before we’re all compelled to eat “right” or less?

Taubes has shown us how bad science can become a new consensus and lead to policy. I hope my attempt to condense his seven hundred pages into a few paragraphs is clear and correct. Why We Get Fat is only two hundred pages. I enthusiastically recommend that you read it. Taubes’ writing is sparklingly clear. His website is garytaubes.com.

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This now completes five years of blogging. January 2012 begins the next five. Here are a couple of follow-ups on previous posts.

On Hitting . . .  Dogs and Children. “With the popularity of The Dog Whisperer television show, books and products, the controversy over which methods are the most humane and effective ways to address behavior problems in dogs is dividing dog lovers all over the world.

“While animal behaviorists, trainers and other dog professionals recognize that the show is exposing dog owners to the possibility that their dogs’ behavior can be changed (and indeed, business is booming), the concern is that the show gives the false impression that behavior can be changed within a matter of hours and that the methods used are known to incite or increase aggressive behaviors.” Read more (1, 2).

Should Spanking Be a Felony? “Is it right or wrong to spank? It is not a question of right or wrong; in a way it is a case of cowardliness, for you are hitting someone not your own size. I don’t suppose you hit your husband when he is being a nuisance. Is it because you wouldn’t dare? He might strike you back. Of course, you’re perfectly safe hitting your child of three. She can’t strike you back.

“Spanking is an outlet for adult rage and frustration and hate. . . . Happy mothers do not spank . . .”

--A. S. Neill (pp. 99-100), Freedom—Not License!

1 comment :

Shehzad Qureshi said...

I would like to thank you for your blog and your book and hope you keep blogging for as long as possible.
Shehzad Qureshi, UK