Why We Get Fat: And What to Do About It (3 page)

Carbohydrate-restricted diets typically (if not, perhaps, ideally) replace the carbohydrates in the diet with large or at least larger portions of animal products—beginning with eggs for
breakfast and moving to meat, fish, or fowl for lunch and dinner. The implications of that are proper to debate. Isn’t our dependence on animal products already bad for the environment, and won’t it just get worse? Isn’t livestock production a major contributor to global warming, water shortages, and pollution? When thinking about a healthy diet, shouldn’t we think about what’s good for the planet as well as what’s good for us? Do we have a right to kill animals for our food or put them to work for us in producing it? Isn’t the only morally and ethically defensible lifestyle a vegetarian one or even a vegan one?

These are all important questions that need to be addressed, as individuals and as a society. But they have no place in the scientific and medical discussion of why we get fat. And that’s what I am setting out to explore here—just as Hilde Bruch did more than seventy years ago. Why are we fat? Why are our children fat? What can we do about it?

Imagine you’re serving on a jury. The defendant is accused of some heinous crime. The prosecuting attorney has evidence that he says implicates the defendant beyond reasonable doubt. He says the evidence is as clear as day and that you must vote to convict. This criminal must be put beyond bars, you’re told, because he’s a threat to society.

The defense attorney is arguing just as vehemently that the evidence is not so clear-cut. The defendant has an alibi, albeit not one that’s airtight. There are fingerprints at the crime scene that don’t match the defendant’s. He suggests the police may have mishandled the forensic evidence (the DNA and hair samples). The defense argues that the case is not nearly as definitive as the prosecutor has led you to believe. If you have reasonable doubt, as you should, you must acquit, he says. If you put an innocent man behind bars, you’re told, not only do you do that person an incalculable injustice, but you leave the guilty party free to strike again.

In the jury room, your job is to assess the claims and counterclaims and make a decision based solely on the evidence. It doesn’t matter what your inclinations might have been when the trial began. It doesn’t matter whether you thought the defendant looked guilty or didn’t appear to be the kind of person who could commit such a horrible act. All that matters is the evidence and whether or not it’s convincing.

One thing we know about criminal justice is that innocent people are often convicted of crimes they didn’t commit, despite
a judiciary system that is dedicated to avoiding just that outcome. A common theme in the litany of justice poorly served is that those wrongly convicted are typically the obvious suspects. Their conviction feels right; evidence that might exculpate them is more easily disregarded. Complicated questions are pushed aside, as is evidence that just might free them after their conviction.

It would be nice to think that science and scientists don’t make such errors, but they happen all the time. It’s human nature. The methods of science are supposed to guard against the adoption of false convictions, but these methods aren’t always followed, and even when they are, inferring the truth about nature and the universe is a difficult business. Common sense can be an effective guide, but as Voltaire pointed out in his
Dictionnaire philosophique
, common sense isn’t all that common, even among scientists, and often what science tells us is that the things that appear to be common sense aren’t. The sun does not revolve around the earth, for example, despite superficial appearances to the contrary.

What sets science and the law apart from religion is that nothing is expected to be taken on faith. We’re encouraged to ask whether the evidence actually supports what we’re being told to believe—or what we grew up believing—and we’re allowed to ask whether we’re hearing all the evidence or just some small prejudicial part of it. If our beliefs aren’t supported by the evidence, then we’re encouraged to alter our beliefs.

It is surprisingly easy to find evidence that refutes the conviction that we get fat because we take in more calories than we expend—that is, because we overeat. In most of science, skeptical appraisals of the evidence are considered a fundamental requirement to make progress. In nutrition and public health, however, they are seen by many as counterproductive, because they undermine efforts to promote behaviors that the authorities believe, rightly or wrongly, are good for us.

But our health (and our weight) are at stake here, so let’s take a look at this evidence and see where it leads us. Imagine we’re
on a jury charged with deciding whether or not it’s overeating—taking in more calories than we expend—that is responsible for the “crime” of obesity and overweight.

A convenient starting point is the obesity epidemic. Ever since researchers at the Centers for Disease Control and Prevention (CDC) broke the news in the mid-1990s that the epidemic was upon us, authorities have blamed it on overeating and sedentary behavior and blamed those two factors on the relative wealth of modern societies.

“Improved prosperity” caused the epidemic, aided and abetted by the food and entertainment industries, as the New York University nutritionist Marion Nestle explained in the journal
Science
in 2003. “They turn people with expendable income into consumers of aggressively marketed foods that are high in energy but low in nutritional value, and of cars, television sets, and computers that promote sedentary behavior. Gaining weight is good for business.”

The Yale University psychologist Kelly Brownell coined the term “toxic environment” to describe the same notion. Just as the residents of Love Canal or Chernobyl lived in toxic environments that encouraged cancer growth (chemicals in the groundwater and radioactivity), the rest of us, Brownell says, live in a toxic environment “that encourages overeating and physical inactivity.” Obesity is the natural consequence. “Cheeseburgers and French fries, drive-in windows and supersizes, soft drinks and candy, potato chips and cheese curls, once unusual, are as much our background as trees, grass, and clouds,” he says. “Few children walk or bike to school; there is little physical education; computers, video games, and televisions keep children inside and inactive; and parents are reluctant to let children roam free to play.”

In other words, we are told, too much money, too much food, too easily available, plus too many incentives to be sedentary—or too little need to be physically active—have caused the obesity
epidemic. The World Health Organization uses the identical logic to explain the obesity epidemic worldwide, blaming it on rising incomes, urbanization, “shifts toward less physically demanding work … moves toward less physical activity … and more passive leisure pursuits.” Obesity researchers now use a quasi-scientific term to describe exactly this condition: they refer to the “obesigenic” environment in which we now live, meaning an environment that is prone to turning lean people into fat ones.

One piece of evidence that needs to be considered in this context, however, is the well-documented fact that being fat is associated with poverty, not prosperity—certainly in women, and often in men. The poorer we are, the fatter we’re likely to be. This was first reported in a survey of New Yorkers—midtown Manhattanites—in the early 1960s: obese women were six times more likely to be poor than rich; obese men, twice as likely. It’s been confirmed in virtually every study since, both in adults and in children, including those same CDC surveys that revealed the existence of the obesity epidemic.
^*

Can it be possible that the obesity epidemic is caused by prosperity, so the richer we get, the fatter we get, and that obesity associates with poverty, so the poorer we are, the more likely we are to be fat? It’s not impossible. Maybe poor people don’t have the peer pressure that rich people do to remain thin. Believe it or not, this has been one of the accepted explanations for this apparent paradox. Another commonly accepted explanation for the association between obesity and poverty is that fatter women marry down in social class and so collect at the bottom rungs of the ladder; thinner women marry up. A third is that poor people don’t have the
leisure time to exercise that rich people do; they don’t have the money to join health clubs, and they live in neighborhoods without parks and sidewalks, so their kids don’t have the opportunities to exercise and walk. These explanations may be true, but they stretch the imagination, and the contradiction gets still more glaring the deeper we delve.

If we look in the literature—which the experts have not in this case—we can find numerous populations that experienced levels of obesity similar to those in the United States, Europe, and elsewhere today but with no prosperity and few, if any, of the ingredients of Brownell’s toxic environment: no cheeseburgers, soft drinks, or cheese curls, no drive-in windows, computers, or televisions (sometimes not even books, other than perhaps the Bible), and no overprotective mothers keeping their children from roaming free.

In these populations, incomes weren’t rising; there were no labor-saving devices, no shifts toward less physically demanding work or more passive leisure pursuits. Rather, some of these populations were poor beyond our ability to imagine today. Dirt poor. These are the populations that the overeating hypothesis tells us should be as lean as can be, and yet they were not.

Remember Hilde Bruch’s wondering about all those really fat children in the midst of the Great Depression? Well, this kind of observation isn’t nearly as unusual as we might think. Consider a Native American tribe in Arizona known as the Pima. Today the Pima may have the highest incidence of obesity and diabetes in the United States. Their plight is often evoked as an example of what happens when a traditional culture runs afoul of the toxic environment of modern America. The Pima used to be hardworking farmers and hunters, so it is said, and now they’re sedentary wage earners, like the rest of us, driving to the same fast-food restaurants, eating the same snacks, watching the same television shows, and getting fat and diabetic just like the rest of us, only
more so. “As the typical American diet became more available on the [Pima’s Gila River] reservation after the [Second World] war,” according to the National Institutes of Health, “people became
more
overweight.”

The italics in the quote are mine, because, you see, the Pima had a weight problem well before the Second World War and even before the First, back when there was nothing particularly toxic about their environment at all, or at least not as it would be described today. Between 1901 and 1905, two anthropologists independently studied the Pima, and both commented on how fat they were, particularly the women.

The first was Frank Russell, a young Harvard anthropologist, whose seminal report on the Pima was published in 1908. Russell noted that many of the older Pima “exhibit a degree of obesity that is in striking contrast with the ‘tall and sinewy’ Indian conventionalized in popular thought.” He also took this picture of the Pima he called “Fat Louisa.”

The obese Pima whom Frank Russell called “Fat Louisa” more than one hundred years ago surely didn’t get fat because she ate at fast-food restaurants and watched too much television
.
(photo credit 1.1)

The second was Aleš Hrdli
ka, who was trained originally as a physician and would later serve as curator of physical anthropology at the Smithsonian Institution. Hrdli
ka visited the Pima in 1902 and again in 1905 as part of a series of expeditions he undertook to study the health and welfare of the native tribes of the region. “Especially well-nourished individuals, females and also males, occur in every tribe and at all ages,” wrote Hrdli
ka about the Pima and nearby Southern Utes, “but real obesity is found almost exclusively among the Indians on reservations.”