Let them eat fat
One of America’s most lauded science writers challenges what we think we know about diet and obesity
In Good Calories, Bad Calories, a carefully investigated 600-page book about the science of obesity, author Gary Taubes lays out the case that it is not too many calories or too much dietary fat that makes Americans grow obese or die of heart disease. Instead, it’s the gobs of sugar, gallons of high-fructose corn syrup and tons of refined carbohydrates that we consume that lead to our demise.
“Despite the depth and certainty of our faith that saturated fat is the nutritional bane of our lives and that obesity is caused by overeating and sedentary behavior, there has always been copious evidence to suggest that these assumptions are incorrect, and that evidence is continuing to mount,” the noted science author writes.
Taubes, author of Bad Science and Nobel Dreams, is a correspondent for Science magazine. He’s won three Science in Society Journalism awards and has contributed articles to The Best American Science Writing 2002 and The Best American Science and Nature Writing 2000 and 2003.
Taubes first espoused the carbs-are-bad concept in his July 2002 New York Times Magazine article, “What If It’s All Been a Big Fat Lie?” While his position was supported by many health professionals, several health experts chimed in with vehement opposition to the article and later to the book. Perhaps the strongest objection came from Michael Fumento in a 2003 Reason Magazine article, “Big Fat Fake,” where he said, “Taubes omitted any reference to hundreds of scientific studies published during the last three decades that contradicted his position. … Since the publication of Taubes’ article, numerous doctors, scientists and health writers have picked apart various pieces of his argument.”
In the Oct. 7, 2007, New York Times Book Review of Good Calories, Bad Calories, “Carbophobia,” Gina Kolata writes, “Taubes ignores what diabetes researchers say is a body of published papers documenting a complex system of metabolic controls that, in the end, assure that a calorie is a calorie is a calorie.” Other reviewers, especially those in the fitness field, object to the lack of emphasis on the benefits of exercise.
Some who agree with Taubes’ low-carb premise complain, however, that the book is a challenging read and plead that what is really needed is a short summation of the book that everyone could read, sort of a Good Calories, Bad Calories Lite.
It wasn’t easy, but somebody had to do it.
Carbs are killers
In Good Calories, Bad Calories, Taubes asserts that while “obesity levels in the U.S. remained relatively constant from the early 1960s through 1980, between 12 and 14 percent of the population; over the next 25 years, coincident with the official recommendation to eat less fat and so more carbohydrates, it surged to over 30 percent.”
Starting in the mid-1970s, and especially with the 1977 release of Sen. George McGovern’s Senate Select Committee on Nutrition and Human Needs’ “Dietary Goals for the United States,” the nutritional focus in this country has been to eat less fat and more carbohydrates. People have been told that the way to lose weight was simple: Eat fewer calories, especially those containing fat, or burn more calories through exercise.
While the so-called experts understood that losing weight was hard, they espoused the view that the public just needed to try harder. Taubes argues that the science behind this low-fat, high-carb diet was never strong, and for the past 100 years, the most effective method of losing weight has always been to reduce the amount of carbohydrates consumed while increasing the amount of fat.
By 1987, when the big push for low-fat diets hadn’t reduced obesity—in fact, it had increased it—there was still no effort to change directions or to question the validity of the science. The only question at that point, Taubes writes, was “whether Americans should be eating low-fat or very-low-fat diets.” No matter how much evidence to the contrary has been provided that low-fat diets don’t decrease obesity, those who provide Americans with recommendations as to what we should eat continue to cling to the low-fat scheme, as does the media.
Good Calories, Bad Calories tells us that humans have been successfully eating high-fat diets for millions of years, while massive quantities of carbohydrates in the diet is a relatively recent phenomena: “The greatest single change in the American diet was that spectacular increase in sugar consumption from the mid-19th century onward, from less than 15 pounds a person yearly in the 1830s to 100 pounds by the 1920s to 150 pounds (including high-fructose corn syrup) by 2000.”
In fact, the increased level of sugar/refined carbohydrate consumption may be the single greatest diet change humans have experienced over the past 2 million years of evolution, and it has happened in a very short amount of time—not enough time for our bodies to evolve to the change.
Taubes’ book talks about how diseases that we have become accustomed to in the United States—obesity, diabetes, cardiovascular disease, hypertension and stroke, some forms of cancer, tooth decay, appendicitis, peptic ulcers, diverticulitis, gallstones and hemorrhoids—are practically nonexistent in native cultures eating non-Western diets. It is only when introduced to sugar, white flour and other refined carbohydrates that native people start fattening up and begin to see these “diseases of civilization.”
Good Calories, Bad Calories is also an indictment of how food science has been conducted in the United States and around the world. Taubes found that many scientists came to the table with a point of view: We need to eat less fat and less meat, and then developed research and studies (and the funding for those studies) to try to support that view. If they found a sliver of evidence to support the low-fat hypothesis and a lot of evidence in opposition, they went with the evidence they wanted to promote.
Taubes also found that bad science happens because scientists in different disciplines don’t talk to each other. When someone studying diabetes found that too much sugar and carbs would raise triglycerides in the blood, which many scientists believe is a more important risk factor for heart disease than the total cholesterol number, there was not a connection made by heart researchers.
“Those investigators concerned with the genesis of heart disease paid little attention, considering anything having to do with insulin to be relevant only to diabetes,” writes Taubes. “This was a natural consequence of the specialization of scientific research.”
The author found that the low-fat diet became the accepted theory of how to eat, because the folks who advocated it were persistent and knew how to talk to the people in government agencies who have the power to influence behavior.
“In the two decades since the NIH (National Institute of Health), the Surgeon General and the National Academy of Sciences first decided that all Americans should consume a low-fat diet, the research has failed to support the most critical aspect of this recommendation: that such diets will lead to a longer and healthier life. On the contrary, it has consistently indicated that those diets may cause more harm than good,” writes Taubes. And yet, almost every doctor and the label on nearly every food product still emphasizes the philosophy of lowering fat intake in our diets. Why?[page]
Part of the answer may lie in the media’s drive to provide a quick and easy solution to every problem. What could be simpler than the theory that eating less fat should make human beings less fat? All it takes is for the public to watch dozens of commercials for cholesterol-lowering drugs showing arteries clogged with fat to make people say, “Geez, I better not eat that stuff.”
Never mind that people have been chowing down on eggs for millennia without particular ill effect. It is now nearly impossible to find any health recommendation in the media that doesn’t talk about eating less fat and more fiber. Those who espoused the low-carb view, such as Dr. Atkins, were reviled by the media as quacks, even though millions of folks who used his diet or other low-carb regimens such as the South Beach Diet reported success in not only lowering their weight but also improving their health.
The opposition to fat is also aided by a drive against the meat industry. Those who promote a vegetarian lifestyle or seek to protect animal rights jumped on the low-fat bandwagon in a big way, telling us all about the evils of animal fats. Much of the public now cringes at the sound of the words “animal fat.”
Take this attitude toward animal fat and combine it with advertisers claiming their product is special because it is low in fat, government agencies drumming into our brains the importance of a low-fat diet, medical professionals telling us that high-fat diets are killing us, and drug companies ceaselessly advertising their best-selling cholesterol lowering drugs, it is no wonder that Americans believe our country’s obesity is primarily fat’s fault.
“The urge to simplify a complex scientific situation so that physicians can apply it, and their patients and the public can embrace it, has taken precedence over the scientific obligation of presenting the evidence with relentless honesty,” Taubes writes.
The carbohydrate hypothesis
A substantial portion of Good Calories, Bad Calories sets out to prove the hypothesis that weight gain and obesity—and a host of diseases related to obesity—are caused by hormonal response to insulin.
The first problem with selling this hypothesis to the public is that it is a complex theory and harder to understand than the idea of simply reducing calorie intake to reduce weight. The gist of the carbohydrate-insulin concept is that your body will burn carbohydrates for fuel and store fat as long as blood sugar is elevated. If you reduce the amount of carbs consumed, your carbohydrate reserves are tapped out, and fatty acids are drawn out of fat tissue into the circulation where they are burned for energy. This is a good thing. According to Taubes, “The one fundamental requirement to increase the flow of fatty acids out of adipose tissue and so decrease the amount of fat in our fat tissue is to lower the concentration of insulin in the bloodstream.”
Carbohydrates on the other hand, increase the level of insulin in our bodies.
“Anything that works to transport more glucose into the fat cells—insulin, for example, or rising blood sugar—will lead to the conversion of more fatty acids into triglycerides and the storage of more calories as fat.” This is a bad thing.
While the drumbeat for a number of years has been that those who gain weight are just lazy and lack willpower, Taubes declared that we eat the massive amounts of carbs that we do because of a physiological addiction.
“So why is it when we add carbohydrates to the diet we get hungry, if not irritable, lethargic, and depressed, but this will not happen when we add only protein and fat? How can the amount of calories be the critical factor?” In fact, Taubes found many studies showing that carbs do not satisfy the appetite, they actually increase it, bringing on the desire for more food.
“As long as we respond to carbohydrates by secreting more insulin, we continue to remove nutrients from our blood stream, in expectation of the arrival of more, so we remain hungry, or at least absent any feeling of satiation. It’s not so much that fat fills us up as that carbohydrates prevent satiety, and so we remain hungry,” he writes. This leads to a situation where the craving for carbs is “closely akin to an addiction. Just like cocaine, alcohol, nicotine and other addictive drugs, sugar appears to induce an exaggerated response in that region of the brain known as the reward center.”
Taubes believes that the scientific evidence that he presents clearly points to the need for a large detailed study on the impact of refined carbohydrates and fat on our diet and health. Such a study may take a decade to complete and interpret, so Taubes urges it to begin immediately.