Food Fight
Experts clash over what to eat for a healthy heart, leaving the rest of us confused. What would happen if you invited three heavy hitters to duke it out before an audience? Some folks at the Medical School decided to see.
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IT WAS THE GREAT FOOD FIGHT, the Thrilla in Vanilla, the Celebrity-Diet-Doctor Deathmatch. The Med School was the venue, and the top of the card featured three of the nation’s diet heavyweights—Dean Ornish, Robert Atkins and Stanford’s own Gerald Reaven—verbally flexing and shadow-boxing in preparation for a battle royal over what people should eat to help keep their hearts healthy. Let’s get stomachs ready to ruuummmble!
Refereeing last May’s match was Stanford associate professor of cardiovascular medicine John Cooke, an expert on dietary supplements, who touted it as “the first conference I know of to bring together the major diet gurus expressly to debate each other.” A serious aim, no doubt, but the organizers gave it a whimsical spin. In his keynote speech, Cooke called the event “a happening” in which the audience of about 150 nutritionists, doctors, nurses and laypeople would participate. Throughout the conference, the audience’s opinions were instantly “biopsied” as people punched electronic keypads at their seats in response to such questions as “What do you think is the right amount of fat in the diet?” Halfway through the proceedings, all audience members used their keypads to take part in a nutrition quiz. Five finalists went to a lightning round of questions, with the winner taking home a bottle of wine.
The audience also voted with their stomachs. At the lunch break, people could select one of three types of meals: high-protein (a turkey sandwich), low-fat (a pasty vegetable concoction wrapped in lavosh bread) or Mediterranean (a green salad with olives). Top choice by far was the Mediterranean. The high-protein came in second, and the low-fat . . . well, who really wants to eat that? During the break, many participants took the opportunity to get on-site readings of blood pressure, heart rate and vascular elasticity (a measure of blood vessel fitness). Consistent with the event’s billing as a “happening,” the lunchtime intermission resembled a collection of political demonstrations. One group warned of the sweet fructose “hidden” in corn syrup, with banners proclaiming: “DON'T GET FRUCTED!” Another cautioned against a form of fat found in many processed foods: “TRANS-FATS KILL!” A third faction proclaimed the benefits of walnuts, while another touted vitamin C as a cure-all.
All the fun had an important purpose, of course. Cardiovascular disease is the biggest killer in the United States. More than 60 percent of Americans are overweight or obese, according to the federal Centers for Disease Control and Prevention, and type 2 (“adult-onset”) diabetes is on the rise, even among children. A key factor connecting these problems and many others is diet, which the panelists agreed is atrocious in the United States. Asian diets, they noted, tend to be heart-healthier, but the reason for this is still in dispute.
What, then, should we eat? With new and often contradictory findings coming out every week, it’s easy to feel like Woody Allen in the 1973 film Sleeper, where he played the owner of a Greenwich Village health-food store who awakens after a hundred-year nap to find that deep-fat frying was ultimately discovered to prolong life. Ornish acknowledged this feeling with a cartoon showing a doctor coming into the examination room with a lab report and telling his patient, “Good news: your cholesterol is the same but the research has changed!”
The Stanford conference was an attempt to sort through the three major dietary arguments by pitting their proponents against each other “live.”
IN ONE CORNER of the ring was Ornish—the dean of diet books promoting an ultralow-fat, vegetarian diet that actually appears to reverse heart disease (Eat More, Weigh Less, Quill, 2000). In the other corner was Reaven (Syndrome X, the Silent Killer, Fireside, 2001), the Stanford researcher who challenged nutritional orthodoxy with his discovery that many people are better off eating more unsaturated fat and less carbohydrate than fat foes like Ornish would suggest. In yet another corner was Atkins, the 71-year-old cardiologist whose no-carb, high-protein, eat-as-much-fat-as-you-want New Diet Revolution (Avon, 1998) captured the popular imagination and launched a commercial empire.
Or rather, Atkins was planning to be in his corner, except that he suffered a heart attack a week before the showdown. According to a statement he released, the cardiac arrest was due to a cardiomyopathy—a pre-existing thickening of the heart wall—and not to any clogging of coronary arteries, which Atkins insists his diet does not cause.
Even without Atkins, there were plenty of fireworks to go around—many directed at Atkins in his absence. Ornish was proudly ornery, giving a respectful tap of the gloves to his colleagues before coming out swinging. He told about speaking at a conference hosted by USDA Secretary Dan Glickman, whose son worked on the movie The Sixth Sense. “I see dead people, too,” Ornish recalled saying. “They’re on the Atkins diet.”
These three, Ornish, Reaven and Atkins, might be said to view the world through lenses made of, respectively, fats, carbohydrates and proteins. Ornish’s solution to the build-up of fatty plaque that clogs arteries is to lower fat intake to only 10 to 15 percent of daily caloric intake. His regimen for heart health also includes stress-management techniques like yoga and meditation. Ornish has some impressive data to show that the diet can not only keep plaque from forming, but also unclog diseased arteries. The problem is that such ultralow-fat diets are hard to stick to and, to some people, not very palatable.
In Reaven’s view, eating extra carbohydrates in place of fats can
be worse than eating the fats themselves. His research suggests that about
one-third of Americans have a heightened risk of stroke, heart attack,
hypertension and type 2 diabetes due to a metabolic problem called insulin
resistance. These people don’t respond effectively to normal levels
of the hormone insulin, which the pancreas secretes to promote storage
of high-energy molecules in the body. Everyone experiences a rise in insulin
levels after eating carbohydrates—but because those with insulin
resistance react sluggishly to the hormone, their bodies must produce
far more than is healthy in order to get the job done.
Eating fat doesn’t spur more insulin secretion; the danger lies in carbohydrates. Eat fewer carbs and you’ll produce less insulin, Reaven says. And while full-blown obesity can contribute to the problem—a heavy load of body fat increases the need for insulin—Reaven stresses that insulin resistance also strikes many who aren’t obese.
Diagnosed through a blood test, insulin resistance is the fundamental defect in a condition that Reaven calls syndrome X. Other manifestations could be high blood levels of triglycerides (fatty substances) and low blood levels of HDL (“good”) cholesterol. A person with syndrome X faces serious cardiovascular risk regardless of his or her weight, Reaven has found. The upshot of his research is that a muscular lifeguard with syndrome X has a far greater chance of heart disease than a flabby couch potato who doesn’t have the syndrome.
To protect people with insulin resistance and syndrome X, Reaven recommends getting up to 40 percent of total calories from fats, primarily unsaturated fats such as olive oil and safflower oil. (The American Heart Association recommends a maximum of 30 percent.) The increase would help people feel full without having to eat too many carbohydrates, he says. Moreover, using unsaturated instead of saturated fats such as butter and lard can lower a person’s blood levels of LDL cholesterol, a major culprit in cardiovascular disease.
Atkins and his adherents tout a diet that is very high in protein, even high in unsaturated fat, as long as carbohydrate consumption stays extremely low. So low, in fact, that wheat, rice and potatoes are out; the only carbohydrates allowed at the beginning of the diet are those consumed in vegetables. The theory is that limiting the body’s main energy source—the glucose that comes from starches—makes the body burn fat for energy instead. The lure for many people is the promise that they can eat lots of food, including lots of fats, and still slim down, enjoying both the aesthetic and health benefits of weight loss. The problem is that a body starved of carbohydrates breaks down its own proteins as well as fats to provide energy, causing muscle wasting and creating toxic by-products that strain the kidneys.
“Everyone knows someone who has lost weight on Atkins,” Ornish snapped. “That’s because they are losing fat, they’re also losing muscle, are constipated and have bad breath, headaches and hair loss.” Atkins counters that his diet, if begun with the blessing of one’s own physician, is a perfectly healthy way of losing weight and reducing weight-related health risks, and that while a few people may get bad breath or become constipated, the vast majority have no side effects at all.
BESIDES SCOFFING at the Atkins diet, Ornish and Reaven managed to find additional points of concurrence as they entered the final round of the match. The two saw eye-to-eye on the cardiovascular benefits of fiber, the omega-3 fatty acids found in oily fish, and the amino acid L-arginine, a popular food supplement also found in nuts, grains and chocolate. Fiber helps moderate insulin levels in the bloodstream. Omega-3 fatty acids may allow us to get away with more fat in the diet. And L-arginine triggers a biochemical reaction that produces nitric oxide, which signals blood vessels to dilate, thereby lowering blood pressure, according to research by Cooke.
Indeed, the value of such supplements was probably the most powerful take-home message from the debate. “That’s the one area where I knew people’s minds were changed,” Cooke said afterward. “In the end, I think there was a greater perception that dietary supplements like L-arginine, fish oil and folate [in spinach and fortified cereals] are a good idea.”
Another consensus was that everyone spends too much time talking about the negatives of a bad diet instead of the positives of a good one. “Fear of dying is not a very good motivator,” Ornish observed. “When you tell someone not to eat something, the first thing they want to do is to go out and eat it. That was true with the very first dietary restriction, when God said don’t eat the apple—and that was God talking.”
IN THE END, the debate wound down to a bloodless draw. A final moment of agreement between the opponents occurred during the question-and-answer period, when someone asked, “Why don’t you talk about the benefits of exercise as much as diet?” The experts quickly responded that exercise is important, that they always say it’s important, that exercise’s importance goes without saying. And then, just as quickly, the talk turned back to diet. The crucial issue of exercise was left by the wayside.
Perhaps that’s because people are drawn to controversy, and there is none concerning the need for exercise. Perhaps it’s because exercise can always be relegated to a distant goal, whereas people have to struggle thrice daily with choices about what to eat. Or perhaps it’s because people just feel so strongly about food, feel deeply that they are what they eat, and then fight to define what they are. “People have a lot of emotional investment in food,” Cooke noted.
Let the food fight go on!
Christopher Vaughan is a science writer based in Menlo Park.
Stanford may not immediately come to mind as a powerhouse in diet studies, but the fact is that many of its strongest medical research areas, like cardiovascular science and endocrinology, have naturally led to investigations of what people eat and how it affects their hearts:
• In the mid-1960s, cardiovascular specialist John Farquhar did pioneering work on obesity, diet, diabetes and fat metabolism. With endocrinologist Gerald Reaven, he discovered that type 2 diabetes can follow from insulin resistance—a sluggish response to insulin.
• In the late 1960s, Farquhar established one of the nation’s first clinics to focus on the role of exercise, nutrition and lowering of cholesterol in preventing heart disease. It later came to be known as the Stanford Center for Research in Disease Prevention.
• In 1971, a trial at Stanford and 11 other centers showed that heart disease could be prevented by lowering cholesterol.
• In the 1980s, researcher William Haskell demonstrated that a combination of diet and exercise with cholesterol-lowering drugs could halt or even reverse clogging of arteries.
• In 1988, cardiovascular researcher John Cooke discovered that the dietary supplement L-arginine helps protect against heart disease.
• In the 1990s, Reaven identified the heart-threatening condition known as syndrome X and showed that it strikes even those who are not obese.
For more: Stanford Center for Research in Disease Prevention