What if it's not overeating that causes us to get fat, but the process of getting fatter that causes us to overeat?"
Recently The Journal of the American Medical Association (JAMA) published a provocative piece that asked precisely that question. Shortly before publishing in JAMA, the authors, summed up their argument in a New York Times Op-Ed: "Always Hungry? Here's Why."
There, David Ludwig, a professor of pediatrics at Harvard Medical School and director the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital, and Mark Friedman, vice president of research at the Nutrition Science Initiative did a superb job of distilling their argument into terms a layman can understand.
They suggest that chronic overeating represents a symptom rather than the primary cause of piling on the pounds. Indeed, Ludwig and Friedman argue, dieting itself may induce changes in our metabolism that leads us to regain weight when we begin to lose it.
They explain their theory: When we eat hearty meals, "we lock . . . more calories away in fat tissue." As a result, "fewer are circulating in the bloodstream to satisfy the body's requirements." In other words, there are not enough calories in our bloodstream to give us the energy to do what we want to do.
"If we look at it this way," they continue, "it's a distribution problem: We have an abundance of calories, but they're in the wrong place. As a result, the body needs to increase its intake. We get hungrier because we're getting fatter."
Ludwig and Friedman compare the process to what happens when patients suffer from "edema, a common medical condition in which fluid leaks from blood vessels into surrounding tissues. No matter how much water they drink, people with edema may experience unquenchable thirst because the fluid doesn't stay in the blood, where it's needed.
"Similarly," they suggest, "when fat cells suck up too much fuel, calories from food promote the growth of fat tissue instead of serving the energy needs of the body, provoking overeating in all but the most disciplined individuals."
Ludwig and Friedman acknowledge that: "many biological factors affect the storage of calories in fat cells, including genetics, levels of physical activity, sleep and stress."
But, they argue, "one has an indisputably dominant role: the hormone insulin. We know that excess insulin treatment for diabetes causes weight gain, and insulin deficiency causes weight loss. And of everything we eat, highly refined and rapidly digestible carbohydrates [like white bread, that dissolves on your tongue and tastes like sugar] produce the most insulin."
Maybe Carbs Are the Culprit After All?
Ludwig and Friedman believe that the increasing amount and processing of carbohydrates in the American diet [as food manufacturers replace fats with carbs] has "increased insulin levels, put fat cells into storage overdrive and elicited obesity-promoting biological responses in a large number of people." In other words, the problem may not be how much we eat (as measured by calories) but what we eat.
"If this hypothesis turns out to be correct, it will have immediate implications for public health," they write. "It would mean that the decades-long focus on cutting calories", a strategy that was "destined to fail for most people. . . . would fade" and "obesity treatment would more appropriately focus on diet quality rather than calorie quantity."
Gary Taubes, author of Good Calories, Bad Calories shares their suspicion about carbs driving fat cells to load up. In an article that drew widespread attention when it was published in BMJ (formerly the British Medical Journal) in 2013, Taubes argues that we gain weight, not because we are gluttons, but because what we are eating is "promoting fat accumulation" and thus "driving an increase in appetite.”
Like Ludwig and Friedman, he is suggesting that we have confused cause and effect. His theory is that dieting encourages our bodies to store fat—and storing fat makes us hungry. One would think that a well-fed, well-padded woman would be less hungry than her skinny sister. But Taubes is saying "No": if the 170-pound sister is dieting, she may well be hungrier.
Needed: New, More Objective Research
Ludwig, Nieman, and Taubes all agree that they cannot prove their theories.
“Unfortunately, existing research cannot provide a definitive test of our hypothesis" Ludwig and Nieman acknowledge. Indeed, they admit, "Several prominent clinical trials report no difference in weight loss when comparing" high protein, low carbohydrate and low fat diets.
But Ludwig and Nieman are not convinced by these trials. They "had major limitations," they explain. "At the end, subjects reported that they had not met the targets for complying with the prescribed diets." Clearly if patients are less than compliant (i.e. they cheat), the results cannot be trusted.
As WIRED reports, Taubes is even more critical of past studies:"Most of the existing knowledge gathered in the past five decades of research comes from studies marred by inadequate controls, faulty cause-and-effect reasoning, and animal studies that are not applicable to humans, WIRED notes.
Taubes' critique is scathing: "The whole body of literature," says Taubes "is based on science that was simply not adequate to the task of establishing reliable knowledge."
In BMJ Taubes suggests that entrenched beliefs have hampered research: "Substandard science is not sufficient to establish reliable knowledge, let alone public health guidelines. When the results of studies are published, the authors must be brutally honest about the possible shortcomings and all reasonable alternative explanations for what they observed."
He goes on to quote Nobel-prize winning physicist Richard Feynman "If science is to progress, what we need is the ability to experiment, honesty in reporting results—the results must be reported without somebody saying what they would like the results to have been—and finally—an important thing—the intelligence to interpret the results. An important point about this intelligence is that it should not be sure ahead of time what must be."
Taubes is now setting out to do the research that he believes we need. Last year, he co-founded a not-for-profit organization called the Nutrition Science Initiative (NuSI.) "Our strategy is to fund and facilitate rigorously well controlled experimental trials, carried out by independent, skeptical researchers," Taubes declared. The Arnold Foundation (a philanthropy founded by former natural gas trader John Arnold), has now committed $40 million over the next three years to this research program."
Some of the top scientists in nutrition research have signed on. Many of them are opposed to Taubes' alternative theory about why we gain weight. But they have been guaranteed the freedom to design and conduct their trials– and oversee reporting–without interference.
To say that the NuSI’s trials are controlled would be an understatement. Patients enrolled in a NuSI study at the National Institute of Health in Bethesda Maryland must stay at the Institute for eight weeks. During that time, they are forbidden to leave. Over the eight weeks, they spend two days of each week insider tiny airtight rooms where scientist can measure exactly how many calories they are burning by measuring changes in oxygen and carbon dioxide in the air. Food is delivered to them through vacuum-sealed portholes. The food itself has been chemically analyzed to ensure an exact number of carbohydrate, protein and fat calories.
If Doctors Know that Cutting Calories Is Not A Solution, Why Don't They Tell Us?
In two years, when the NuSI study ends, we may well know much more about carbs vs. protein and fat.
But even in 2008, when I first wrote about obesity, it was becoming clear that curtailing calories and hitting the treadmill would not lead to long-term weight loss. Conbtrolled trails supervised by physicians revealed that up to 95% of patients would put the pounds back on.
Why didn't someone tell us?
First, keep in mind that the weight loss industry—which sells diets, pills ,and other products—spends billions o advertising..This could be one reason why the mainstream media has been slow to tell us that losing weight the conventional way is all but impossible for most of us.
Moreover, newspaper editors and television producers know that the American public doesn't like to hear discouraging news about what modern medicine can and can't do. We prefer to believe that there is a "cure" for everything—including "curves."
Secondly—and this is terribly important—our doctors live in the same culture that the rest of us do. As the first post in this series illustrates (URL) ) family doctors who don't specialize in obesity tend to share the popular belief that weight loss is all about "calories in and calories out’—how much you stuff into your mouth, and how much energy you expend. As I explain in that post, this is understandable. In our med schools, few students study obesity.
But what about the experts who know the research. Why haven't they warned us that yo-yo dieting won't get us anywhere?
In fact, some have tried. But as University of Alberta professor Tim Caulfield, who researches and writes about health misconceptions confides, his fellow obesity academics "tend to tiptoe around the truth."
Last year, he told CBS News: "You go to these meetings and you talk to researchers, you get a sense there is almost a political correctness around it, that we don’t want this message to get out there. You’ll be in a room with very knowledgeable individuals, and everyone in the room will know what the data says and still the message doesn’t seem to get out.”
In part, that is because it’s such a harsh message. “That’s one of the reasons why this myth of weight loss lives on," says Caulfield.
"Health experts also are afraid people will abandon all efforts to exercise and eat a nutritious diet — behavior that is important for health and longevity," explains CBS medical correspondent Kelly Crowe "even if it doesn’t result in much weight loss."
Nevertheless, Traci Mann, the psychologist who has spent 20 years running an eating lab at the University of Minnesota, declares that, at this point in time, "the emphasis should be on measuring health, not weight.
“You should still eat right, you should still exercise, doing healthy stuff is still healthy,” she declares. “It just doesn’t make you thin."
But you will live longer—and, most importantly, enjoy life more.