by Meghan Johnson
The Friedman Seminar Series hosted journalist, Gary Taubes, on March 30th to talk about his latest book Why We Get Fat. You may find it curious to refer to Mr. Taubes as a journalist and not a nutritionist or medical doctor when you hear the title of his text. But Mr. Taubes is, in fact, a Robert Wood Johnson Foundation independent investigator in health policy and holds a degree in physics from Harvard University.
He first made waves in the nutrition community with a piece published in New York Magazine in 2001 called What if It’s All a Big, Fat Lie. In this exhaustive article, Taubes suggests that the public health community might have gotten it all wrong and Dr. Atkins might be onto something with his no carbohydrate diet revolution.
Taubes’s article sparked so much debate that his publisher awarded him a book advance to flesh out his postulates by spending almost five years talking to over 600 experts and conducting an intensive literature review around lipid metabolism and why we get fat. His first iteration of his book, called Good Calories, Bad Calories, was published in 2007 and contained over 600 pages. Since then, he must have realized that today, people like to be spoon-fed their health information in a more consolidated format. His most recent book is a scaled version of Good Calories, Bad Calories and weighs in at around 200 pages.
What is a physicist doing to make waves in the nutrition and public health community?
Taubes’s main argument is that carbohydrates, and especially sugar (as he elaborated on in his latest New York Magazine article, “Is Sugar Toxic?”), are the sole cause of obesity. He claims that this is because refined carbohydrates negatively affect our bodies’ insulin secretion, and thus the hormonal regulation of homeostasis. The more easily digestible and refined the carbohydrate we consume, the greater the effect on our weight and disease-risk.
Taubes makes several other controversial claims, including that dietary fat does not cause heart disease and that obesity is a disorder of excess fat accumulation, not the result of sedentary behavior and/or overeating. In his book, he goes to great lengths to explain that excess energy consumption and sedentary behavior actually result from the body storing energy as fat, thus needing to consume more energy for bodily functions.
To illustrate this argument, he relies on several populations from the 19th and early 20th Centuries (the Sioux Indians, the Pima Indians, factory workers in Chile, etc) where people were very poor and had little to eat besides staples such as bread, corn and coffee, and yet still maintained moderate to high levels of obesity. Similarly, some of the populations he describes, such as Chilean factory workers, were very physically active, yet overweight. Repeatedly during his presentation (I was able to see it twice, first at the Friedman School and again at Harvard, presented by the Harvard Food Law Society), he asks “Why were these people fat?” After all, they have no drive-thrus, no sodas, no supersizing, and no obesogenic environments.
What Gary Taubes tries to do is to challenge one of the core principles of energy balance (endorsed by the USDA, the American Heart Association, the American Medical Association, American Dietetic Association and other reputable institutions) that calories consumed must nearly equal calories expended in order to maintain body weight. The USDA and Department of Health & Human Service’s 2011 Dietary Guidelines for Americans state, “Eating and physical activity patterns that are focused on consuming fewer calories, making informed food choices, and being physically active can help people attain and maintain a healthy weight, reduce their risk of chronic disease, and promote overall health.” The First Law of Thermodynamics supports this theory of energy balance, something a physicist knows all too well.
What should we make of it?
Dr. Alice Lichtenstein is a Senior Scientist and Director of the Cardiovascular Nutrition Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University. She received her D.Sc. in Nutritional Biochemistry from the Harvard School of Public Health and has focused her research primarily on dietary fatty acids, nutrition, lipoproteins, and cardiovascular disease risk over her lengthy and distinguished career. She also attended Mr. Taubes’s lecture at the Freidman School.
I asked Dr. Lichtenstein if she could help demystify some of the information presented in Mr. Taubes’s book, which can seem quite compelling. “One of the issues is that one has to look at the totality of the data and one can’t… ‘cherry-pick’ specific studies that made certain observations, some of which are still valid today and some of which aren’t,” she said. “You can’t simply rely on the original study to assess a situation in 2012 because we look at a broader range of biological outcomes, we have more precise methods for measuring things and we are more likely to take factors into consideration that can impact the biological outcomes that weren’t taken into consideration in some of the early reports” she said in reference to Mr. Taubes’s use of populations from 100-200 years ago to support his claims.
In response to Mr. Taubes’s allegation that carbohydrates are uniquely contributing to obesity and that, by removing carbohydrates from the diet, people could consume energy in excess without gaining weight, Dr. Lichtenstein said, “At this point I haven’t seen adequate data to show that there is enough of a difference in the calories coming from fat, carbohydrates, protein and alcohol to make a difference. I think the major determinant is that total number of calories consumed and the total number of calories burned. If you consume a diet that’s really high in fat and protein and you consume it in excess of energy needs, you will gain weight. If you consume it in inadequate amounts to maintain body weight, you’ll lose weight.”
Dr. Lichtenstein has been in the field of nutrition long enough to see many diet trends come and go; from low fat to low carbohydrate to grapefruit diets, she’s weathered them all. Mr. Taubes tries to distinguish himself from Dr. Atkins, emphasizing this is not “that Atkins stuff again.” Yet one must wonder, if we followed Mr. Taubes’s advice, what type of foods would we consume? We’d be eating foods that are high in protein, high in fat, low in fiber, and low in key nutrients such as vitamin C and potentially calcium. Whether or not we’d lose weight may not be the issue so much as, would we be healthy?
When dispensing nutritional advice, one must also consider feasibility and sustainability of the diet. A short-term weight loss that cannot be sustained over time due to food fatigue (when people tire of eating the same limited foods over time) is not a feasible solution to the obesity epidemic. Dr. Lichtenstein said, “Initially with any diet, if it’s restrictive, there’s a huge category of foods that is eliminated but look what happens with fad diets. In the low-carb phase, we got low-carb brownies, low-carb candy, low-carb pasta and then we when we were in the low-fat phase, we got low-fat ice cream and low-fat cookies, etc. Even if initially it works because we are eating less because there are just fewer options, ultimately we figure out how to eat around the dietary restrictions and how to create more options.”
Take it with a Grain of Salt
While it is important to be skeptical consumers of health information and to be open to new ways of looking at the multi-faceted condition of obesity, we must do so with a solid grounding in science. Mr. Taubes, a compelling and well-researched journalist, makes a strong case for refuting what the public health community has held to be true for decades. Some of his postulates certainly hold water; for some, reducing carbohydrates in the diet may spur weight loss. For some, increasing protein and fat in the diet will not lead to weight gain or have negative health implications. And for others, exercise may not be a major factor in preventing weight gain over time.
But overall, decades of research using modern and precise measurements from highly trained scientists tells us that the best ways to maintain optimal health and weight is to eat a balanced diet, one containing fiber-rich carbohydrates, vegetables, fruits, legumes, low-fat dairy and lean meats and to exercise moderately to vigorously each day, as the Dietary Guidelines for Americans recommend. Keep in mind that no diet works well for everyone as the human body is comprised of complex systems, influenced by personal preferences and behaviors in addition to genetics. Nutrition is a relatively new science that is dynamic, as all sciences are, and constantly re-evaluating and testing its postulates.
Mr. Taubes also seems to overlook some of the similarity in his message and that of the health community. For example, no registered dietician that I have come across is advocating for people to consume carbohydrates in the form of sodas, desserts, refined grains, or excess snack foods. Aren’t we all on the same team here?
As far as his attempts to refute the First Law of Thermodynamics (that energy in does not need to balance energy out), Dr. Litchenstein told me with a sigh, “Everyone wants to believe you can have your cake and eat it too. My basic feeling is that unless you take the cake, and put it on your head and run around the block, it just doesn’t work.”
Meghan Johnson is a first-year FPAN student with a specialization in Health & Nutrition Communication. She relocated to Boston from Washington DC and is doing her best to acclimate to the lingo, the bitter winds, and clam chowder.