Just inside the door of Willett’s office at the Harvard School of Public Health in Boston sits his bicycle, mud-spattered from his daily commute over the Charles River from his home in Cambridge. Past that, on top of a pile of medical journals, perches a plastic bag full of Three four-inch pancakes (33 grams of carbohydrates) for breakfast with a quarter cup of syrup (52 grams of carbohydrates) is equivalent to eating 21 teaspoons of refined sugar. The glycemic index of the meal is about 65 (medium). The glycemic load for the pancakes is 27 (high) and 28 (high) for the syrup.
plump, homegrown cherry tomatoes, a late-season-harvest gift from his administrative assistant. Willett knows good tomatoes. As a member of a fifth-generation Michigan farming family, he paid his undergraduate tuition at Michigan State by raising vegetables, and today he grows “as much as possible” in his tiny urban backyard.
Behind the cluttered desk sits Willett himself, trim, toned, and turned out in a sharp gray suit. “All you have to do is take a look at Walter to see the value of his research. The proof is in the pudding,” says David Jenkins, a nutrition researcher at the University of Toronto. Willett vigorously follows his own plan and at age 58 reports that his weight, cholesterol, and triglycerides are all where they should be. He is, in short, the picture of where applied nutritional science might deliver us all, if we had the proper information.
That’s the problem. In recent years, Willett says, the American public has been victimized by dodgy advice. Not only has obesity skyrocketed but “the incidence of heart disease is also not going down anymore. It has really stalled.”
What happened? In Willett’s view, things began to go awry in the mid-1980s, when a National Institutes of Health conference decreed that to prevent heart disease, all Americans except children under 2 years old should reduce their fat intake from 40 percent to 30 percent of their total daily calories. The press touted the recommendation as revealed truth, and the USDA’s Food Guide Pyramid, released in 1992, reflects this view, calling for 6 to 11 servings of bread, cereal, rice, and pasta daily, while fats and oils are to be used “sparingly.”
Too bad, says Willett. “The low-fat mantra has contributed to obesity. The nutrition community told people they had to worry only about counting fat grams. That encouraged the creation of thousands of low-fat products. I call it ‘the SnackWell revolution.’” Blithely consuming low-fat foods full of carbohydrates is a prescription for portliness, says Willett, adding that any farmer knows this. “If you pen up an animal and feed it grain, it will get fat. People are no different.”
The problem with overeating refined carbohydrates such as white flour and sucrose (table sugar) is that amylase, an enzyme, quickly converts them into the simple sugar called glucose. That goads the pancreas to overproduce insulin, the substance that conducts glucose into the cells. But excessive sugar is toxic to cells, so after years of glucose and insulin overload, the cells can become insulin resistant and may no longer allow insulin to easily push glucose inside them. That keeps blood glucose levels high, forcing the pancreas to make even more insulin in a desperate attempt to jam the stuff through cell membranes. Willett likens the effect to an overworked, undermaintained pump that eventually wears out. Type 2 diabetes can be one result, but Willett contends that insulin-resistant people who don’t develop full-blown diabetes still face significant health risks.
Other researchers agree. Stanford endocrinologist Gerald Reaven coined the term Syndrome X to describe the constellation of health problems that spring from insulin resistance. Until the late 1980s, Reaven says, “the common scientific view was that insulin resistance only mattered if it led all the way to type 2 diabetes. Looking at the data, it’s clear that most people who are insulin resistant don’t get diabetes but are greatly at risk for coronary heart disease, hypertension, non-alcoholic-type liver disease, polycystic ovary syndrome, and several kinds of cancer.”
| WILLETT VS. ORNISH VS. ATKINS
Walter Willett’s dietary recommendations are similar in many ways to those advanced by another doctor-nutritionist, Dean Ornish, who pioneered an ultralow-fat, near-vegetarian regime that has been shown to halt or reduce coronary blockage in most heart patients. Both Willett and Ornish emphasize whole grains, fruits, and vegetables, and both minimize animal proteins. But they part ways on fats: Willett recommends replacing saturated fats in the American diet with unsaturated ones, while Ornish suggests sharply cutting fat intake altogether, especially for those at risk for heart disease. “No one has shown that the kind of diet that Walter Willett recommends can reverse heart disease,” says Ornish. For his part, Willett insists that “replacing saturated fats with unsaturated fats is a safe, proven, and delicious way to cut the rates of heart disease.” He says the Lyon Diet Heart study, a French trial that tracked heart-attack survivors on an oil-rich Mediterranean diet versus those on the low-fat American Heart Association diet, showed a significant drop in second attacks for the Lyon group. Ornish responds that the drop in deaths in that study was most likely due to increasing heart-healthy omega-3 fats and decreasing intake of omega-6 fats, saturated fats, animal protein, and cholesterol, not to high overall consumption of fat. Ornish recommends that everyone consume three grams of omega-3 fats daily, either through eating fish or taking supplements. In contrast with both Willett and Ornish, the late Robert Atkins recommended a meat-intensive, protein-rich regime. “Studies at Duke University, the University of Cincinnati, and the University of Pennsylvania all show that people can lose significant weight, lower their triglycerides, and improve their HDL [high-density lipoprotein] cholesterol levels by consuming protein and limiting carbohydrates,” says Stuart Trager, an orthopedic surgeon who assumed the spokesman’s mantle for the diet after Atkins’s death in April 2003. Trager believes the real strength of the Atkins diet is that “it is something people are willing and able to do.” Willett concedes that Atkins “was really onto something. He believed, correctly, that most people can better control their weight by reducing the glycemic load of the diet than by other means. But there is evidence that the traditional Atkins diet, which is high in animal fat, is not optimal. There are benefits to having cereal in one’s diet. There is relief from constipation, and we do see [in the Nurses’ Health Study] some benefit for heart disease and diabetes. This is probably partially from the fiber in whole grains, and also partly from the other minerals and vitamins that come along with whole grains that are in short supply in many people’s diets.” While at first blush the three approaches seem sharply divergent, Trager sounds a conciliatory note. “No one has ever bothered to point out that we are compatriots on many points,” he says. All three nutritionists share an emphasis on reducing blood-sugar spikes by reducing the glycemic load. Moreover, all three condemn trans fats, white flour, and sugar. “There really is universal agreement that you should cut those things out of your diet,” Trager says. —Brad Lemley |
