An eye-opening new book on human nutrition may challenge everything you believe about what America eats and why so many struggle with obesity.
Hold the rice. Hold the potatoes. Hold the pasta. The low-fat diet our government has been serving up through USDA's “Dietary Guidelines for Americans” may be the root of this country's obesity epidemic.
That's just one of many controversial conclusions author Gary Taubes draws in his book, “Good Calories, Bad Calories,” published in 2007 by Random House.
He has a point. Researchers and public health authorities have promoted low-fat, high-carbohydrate diets since the 1980s, and USDA reports that dietary fat intake has decreased significantly. But obesity has increased markedly since 1980 — right along with an increasing consumption of carbohydrates and sugar.
In fact, in 2009, according to the Centers for Disease Control and Prevention, more than one-third of adults and 16% of children in the U.S. are obese. The finger of blame typically points to dietary fat, overeating fast food and television- or computer-induced sedentary behavior.
In contrast, Taubes argues the key to good health is the kind of calories we take in — good or bad — not the number. His 500-page book is thorough and by no means a quick read. It's the product of seven years of research in every science connected to nutrition and human health, and it brings good news for beef consumers. The book says the fundamental problem with America's eating habits is not the dietary fat in your cheeseburger. The problem is the refined carbohydrates — like the flour in the bun, the starchy french fries on the side, and the high-fructose corn syrup in the soft drink.
About the book
“Good Calories, Bad Calories” stems from “What if It's All Been a Big Fat Lie?” — a highly controversial article Taubes wrote for New York Times magazine in July 2002. The aim was to research what could be causing the obesity epidemic, and the article triggered an uproar. It accuses the American medical establishment of basing its dietary recommendations on bad science.
“We tend to think of science evolving through this process of hypotheses and tests, and then the things that get accepted are things that were rigorously tested over the years,” Taubes says. “None of that happened in obesity research.”
An award-winning science journalist and a contributing correspondent for Science magazine, Taubes specializes in science controversies and says he recognizes bad science like an English teacher recognizes bad writing.
While he isn't a medical doctor or nutritionist, Taubes has a solid background in science. He studied applied physics at Harvard and aerospace engineering at Stanford before earning his master's degree in journalism at Columbia University.
For the book, Taubes interviewed more than 600 clinicians, investigators and administrators.
“I went back through all of the research since the 19th century to see if what they were telling me was supported by the science,” he says. “Often it wasn't. It's that simple.”
Taubes says he found the quality of research on nutrition, obesity and chronic disease very inadequate and much of the conventional wisdom about nutrition to be founded on insubstantial evidence.
Carbs vs. fat
Surprisingly, the conventional wisdom that a low-fat diet is a healthy diet has only been accepted for about 30 years, Taubes explains. Up until the 1960s, the accepted wisdom was that carbohydrates make you fat and — what's more — that fat and protein protect against overeating by making you sated.
“Carbohydrates literally keep you hungry, whereas fat and protein do not,” he says. And the scientific evidence supports this hypothesis. In the late 1950s and mid 1960s, biochemists and other researchers figured out that the hormone insulin regulates fat and pointed to carbohydrates as the cause of overweight and obesity.
“It's not how many total calories you eat. It's the quality and quantity of carbohydrates,” Taubes says.
For example, 1,500 calories of pasta could make you gain weight when 1,500 calories of meat will not. The carbohydrates in pasta will drive up insulin levels, and the insulin will tell your fat tissue to store these calories as fat. The glucose is swept away into fat and muscle cells, and this all tells your body to prepare for more food to come.
“It's like emptying out a storage space so you can continue to throw in more,” he says, concluding that obesity is a disorder of excess fat accumulation, rather than overeating or sedentary behavior.
What's more, Taubes says refined carbohydrates are likely the dietary cause of coronary heart disease and diabetes because of their direct effect on insulin and blood sugar. In addition, refined carbohydrates, starches and sugars are the most likely environmental causes of cancer, Alzheimer's disease and other chronic diseases of civilization, he says.
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The role of science is to question everything. Health authorities today, however, have forgotten this role, as well as the conventional wisdom of the 1960s, Taubes says. America's medical establishment inherited a paradigm — a way of thinking about obesity — that seems to be commonsense and indisputable. They've never questioned it and see no reason to test its validity.
This inheritance was largely the work of six men who dominated obesity research in the 1970s. These men, convinced that overeating causes obesity, hosted all the conferences, wrote the proceedings and then authored the textbooks on obesity.
“They decided what the science was, and they came up with this idea that the physiological, biochemical regulation of fat tissue is irrelevant to why we get fat,” Taubes says.
By addressing obesity as a problem of overeating, they put the problem in the brain. It is as if to say, “You eat too much because you just can't help yourself. If you ate less, you'd be thinner.”
This meaningless concept, he says, is a misinterpretation of the laws of thermodynamics.
What's more, at least two of the six leading researchers knew Robert Atkins, the physician and cardiologist best known for the popular low-carbohydrate, high-protein Atkins diet. They thought Atkins' high-fat diet would give people heart attacks, and thus didn't actually care if it was the only functional way to lose weight. In their minds, Atkins was going to kill people by telling them to eat cheeseburgers and other foods loaded with saturated fat. So, to diffuse the Atkins phenomenon, these men threw out the science.
“They wanted to get rid of Atkins — the bath water — so they threw out the baby with him, which was the science that says: Carbohydrates make you fat. If you don't eat carbohydrates, you won't be fat,” Taubes says.
Since Taubes started his research, the results of more than half a dozen clinical trials of the Atkins diet have been published. Virtually all show people on the Atkins diet not only lose weight but improve their cholesterol profiles.
The gist of the Atkins diet is to avoid starchy vegetables and sweets and don't shy away from dietary fat. Eat eggs, meat, chicken and fish, and supplement those with green leafy vegetables, cheese or nuts.
Taubes says it's hard to imagine how this can be unhealthy because the carbohydrates you avoid don't bring many vitamins or minerals into the diet anyway.
The idea that consuming too many low-quality carbohydrates makes people gain weight is a simple, legitimate hypothesis that's never been refuted, Taubes says. Even so, he's typically met with blank stares when he lectures to obesity researchers.
“Often, I'll get the comment, ‘It just can't be that simple.’ I'll say, ‘No, actually it can be that simple. The way science works is you're supposed to be able to refute the simple hypothesis,’ ” he says. “Only if you can refute the simple hypothesis can you then start complicating it in order to explain whatever it is you are studying.”
One nutritionist from New York University told Taubes it may take a lifetime to get people to accept what he's saying.
Shalene McNeill, executive director of human nutrition research for the National Cattlemen's Beef Association, says Taubes' proposition is important.
“His evaluation and deeper review of the scientific evidence certainly calls into question some long-standing ideas,” she says. “It's a good scientific exercise.”
But McNeill says there's not one simple prescription for curbing today's obesity epidemic. And because the book challenges conventional wisdom, most nutritionists regard it with at least some skepticism.
“Most want more evidence,” she says. “But there's a lot of merit to the book, and it has prompted a tremendous amount of research.”
The book, she says, goes right along with the latest research in rediscovering the importance and benefits of protein in the diet. Beef is the number-one source of dietary protein.
Right now, many nutritionists are debating whether a calorie is a calorie. She says high-protein diets can decrease appetite, reduce calorie intake and help you maintain a lean body mass.
The body of scientific evidence supporting protein's beneficial role in weight management is growing. The science is there, McNeill says, and the beef industry is now able to leverage it to influential leaders in the nutrition community.
“This is exciting news for beef consumers,” she says, “because they can incorporate more beef back into their diets.”
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An urgent appeal
Taubes often speaks to clinicians, nurse practitioners and obesity researchers about his findings. Earlier this spring, Taubes presented to the National Institutes of Health's Nutrition Coordinating Committee, trying to convince the group that his hypothesis must be taken seriously.
“We have this obesity epidemic and the diabetes epidemic, and they are predicted to overwhelm the health care system,” he says. He notes that obesity increases the risk of getting diabetes, coronary heart disease, cancer, Alzheimer's disease and other chronic diseases of civilization.
“Whatever is making us fat is also making us sick,” he says.
And Taubes' urgent appeal to those leading the nutrition establishment is to question their own beliefs.
“Obviously,” he says, “what they have been telling us hasn't worked.”
Besides lecturing, Taubes is working on an easier-to-read book, which he refers to jokingly as “Good Calories, Bad Calories Lite.” The actual working title is “Why We Get Fat.”
“I want it to be something that everyone can read so they really understand how the science works,” he says.
He intends to explain why some people gain weight and their friends don't, and why some gain weight as they age or when they get pregnant or when they drink beer.
“I want to directly challenge the belief that it's all about this meaningless concept of overeating,” he says.
Diana Barto is a freelance writer based in Waconia, MN, and a former BEEF senior associate editor.