A BETTER WAY TO EAT!
Americans have grown fatter and sicker since the USDA Food
Pyramid came out a decade ago. Is there a healthier, tastier diet?
by: Geoffrey Cowley
NEWSWEEK Jan. 20, 2003
S OMETHING IS WRONG, if not rotten, in the state of New York, the state of California and every state in between. While searching endlessly for just the right diet, we’re consuming ever more calories, growing ever more obese and suffering obscene rates of diabetes, hypertension and heart disease as a result. No one outside the weight-loss industry is happy about the situation, but as the crisis worsens we seem to grow ever more confused about how we got here—and ever more polarized about how to set things right. Die-hard vegetarians continue to rail against dietary fat and emulate Chinese peasants. Born- again carnivores blame the White Devil (a.k.a. bread) and force themselves onto all-meat diets in hopes of incinerating their belly fat. Ordinary civilians throw up their hands and consume whatever is convenient—which is to say Krispy Kremes and Coke.
IS THIS THE COST OF MODERNITY? Have we escaped scurvy, pellagra and rickets only to suffer higher-tech forms of malnutrition? Somewhere in the fog of conflicting prescriptions, is there a diet that’s both safe and palatable—a diet that can control weight and promote health without denying us the pleasure of food?
The federal government has long tried to distill the best science on diet and health. But commercial pressures and bureaucratic obstacles have often clouded the results.
The USDA’s famous Food Guide Pyramid, first published in 1992, is now widely viewed as flawed. “The pyramid is a disaster,” says K. Dun Gifford of Oldwavs, a non-profit think tank based in Boston. “The American epidemic of obesity is the proof that it hasn’t worked. Period. Amen.”
That doesn’t mean all such efforts are doomed. Researchers have gained critical insights into diet and health in recent years. And while they wait for the USDA to remodel its now crumbling pyramid, some of those experts are concocting whole new alternatives. By far the most ambitious of these efforts is the so-called Healthy Eating Pyramid devised by Dr. Walter Willett and his colleagues at the l-larvard School of Public Health. Instead of simply pooling diet preferences, the Willett team claims to have distilled the best evidence from all possible data sources, including Harvard’s huge Nurses’ Health Study, Physicians’ Health Study and Health Professionals Follow-Up Study. The Healthy Eating Pyramid has some controversial features, including a strong endorsement of calorie-rich vegetable oils and a virtual prohibition of potatoes and white rice. But its health effects have been cleverly evaluated and affirmed. The diet is designed not for short-term weight loss but for lifelong health. It doesn’t require that you weigh your food or eat according to your blood type or astrological sign. As Willett likes to say, its ultimate message is simple: “Eat, drink and be healthy.”
The main difference between the Healthy Eating Pyramid and the government’s plan is its focus on individual foods. Willett is quick to break up groups of fats or carbohydrates or proteins to highlight the best and worst sources of those nutrients. That may seem an obvious distinction, but it’s a critical departure from the USDA’s recommendations. Instead of directing people to the best flits, the most wholesome carbohydrates and the most nutritious sources of protein, the USDA pyramid implies that all fats are dangerous and most carbs arc safe. And if the past decade has taught us anything, it’s that carhs can he as deadly as fats.
How did the government get it so wrong? Basically by trying too hard to simplify its message . Scientists have known since the 1960s that the saturated fat in red meat and dairy products can raise cholesterol levels and promote coronary heart discase. Though the USDA had long down-played those risks to appease the cattle and dairy industries, it had also acknowledged them. When the USDA staff started building the Food Guide Pyramid in the late 1980s, its main objective was to get that message out. Earlier food charts had shown four basic groups—meat, dairy, produce and cereal grains—and encouraged people to eat everything in moderation. The pyramid introduced the notion that some foods (fats) required more moderation than others (carbohydrates).
Scientists were well aware that fats could be healthful and that carbs could cause harm. Studies had shown that unlike butter and lard, the oils found in fish, nuts and vegetables helped protect against heart disease—and that cereal grains had all the nutritional value of table sugar when milled into flour. But instead of trying to convey these insights, the USDA focused on the situation at hand. Americans were getting most of their fat from meat and dairy products. The agency’s advisers reasoned that any reduction in fat would mainly affect saturated fat. And if people replaced the lost meat with starch, at least they would lose some calories.
If the environment hadn’t changed, the strategy might have worked. But foodmakers soon discovered the potential of low-fat processed foods. Cereal grains aren’t very profitable in raw form, notes Elizabeth Pivonka, president of the Produce for Better Health Foundation. “If you puff them, sweeten them and put them in a box with a picture on the front and a toy inside, you can charge a lot more.” The pyramid consigned sweets to a small chamber labeled “use sparingly,” but as low-fat cakes, cookies and snacks flooded the market in the early 1990s, consumers simply added them to what they were already eating, falsely assuming that anything low in fat must he harmless. “We were trying to promote lean meats and low-fat dairy products,” says Marion Nestle, a New York University nutritionist who served as an adviser to the surgeon general in the late 1980s. “We never thought of Snackwell’s.”
It’s not just the calories that make refined carbs so troublesome—it’s the way they’re digested. Unlike whole grains, which break down slowly in the digestive system, refined grains flood into the bloodstream as glucose. If that sugar isn’t used immediately to fuel activity, the body produces a burst of insulin to ferry it out of circulation and into fat and muscle cells for storage. As most people now know, a diet rich in refined carbs and simple sugars can erode that system. Cells become increasingly resistant to insulin, forcing the body to produce it in ever-greater amounts. Eventually the system breaks down, triggering diabetes and fostering heart disease. An occasional glucose surge is no great hazard to a lean, active person. But as Willeft observes, Americans were neither lean nor active when they started mainlining carhs. Small wonder that the rate of type 2 diabetes soared during the ‘90s.
Though experts bicker endlessly about how best to reverse these trends, no one denies that weight management is critical. So little progress was made hefbre 1953, when one of medicine’s more famous patients arrived on the scene. An epileptic, H.M. suffered intractable, frequent seizures until he had both of his temporal lobes removed. Now deprived of his hippocampus, H.M., like the protagonists of the movies “Memento” and “50 First Dates7 was unable to form new memories of people, places or things.
The unfortunate patient’s case clearly signaled that the hippocampus played a central role in memory formation. But two more decades would go by before researchers figured out why or how “The biology of memory storage was really a black hole,” says Kandel. “We knew very little about it 25 years ago:’ Kandel’s idea—to use a deceptively simple organism to solve a complex problem—met with skepticism. No wonder, says Siegelbaum, a longtime collaborator of Kandel’s: “Most people were working on very basic problems. It was sort of an audacious goal at the tune:’ But audacious goals often drive equally audacious science, and Kandcl, working with his sea snails, was on to something. Because the snails had such large neurons, and so few of them, Kandel was able to identify the individual nerve cells responsible for specific behaviors. Those nerve cells appeared to rely on some of the same biochemical processes that power the brains of more-advanced animals. Aplvsia californicus turned out to be a good model for molecular memory processes in humans. Both species rely on the neural messenger cyclic AMP, which modulates a protein called CREB that can turn genes on or off CREB is the brain’s sculptor: it forms memories by reshaping the synapses, or spaces between neurons. So changes in cyclic AMP levels—and corresponding changes in CREB levels—affect the brain’s ability to remodel its synapses. Less CREB equals less memory-making ability.
The practical results of this work, as well as extensive follow-up tests in mice and rats, are several new drugs now in early development at Memory Pharmaceuticals, founded in part by Kandel in 1998. MEM1414 is the inheritor of the Aplvsia findings. Cyclic AMP, the neurotransmitter that dictates CREB levels, is normally degraded in the brain by enzymes called phosphodiesterases. By inhibiting those enzymes’ activity, MEM14 appears to boost CREB levels and enhance the brain’s long-term memory functions; researchers hope it will enhance long-tern memory in patients with age-related forgetfulness and even ward off the early stages of Alzheimer’s disease, even though the two ailments arc not related. There’s also MEM19I7, a drug similar to 1414; MEM1003, which protects neurons from damaging overloads of calcium, and MEM3454, a schizophrenia treatment that targets a receptor also known to respond to nicotine. Researchers think that some schizophrenics ease their symptoms, including loss of memory function, by self-medicating with cigarettes.
Other companies are also in the hunt. Helicon has a phosphodiesterase inhibitor of its own. Sention, co-founded by Mark Bear of the Picower Center for Learning and Memory at MIT, has gone chemicallv “upstream” of cyclic AMP and CREB, modulating the fleurotransmitters that direct the synthesis of proteins the brain uses as the basic building blocks of memory. Its intriguing new drug, C105 (which is largely under wraps for now), is in phase II trials. Cortex Pharmaceuticals, one of the oldest memory-booster firms, is focusing elsewhere, on molecules called ampakincs, which modulate “AMPA receptors” in the brain that can strengthen the synapses. The company already has one drug, CX516, through phase II trials, although it is too weak to be a practical prescription option. A revved-up version, CX717, is in the works, and several other companies are also developing their own ampakines.
Researchers are reluctant to sing the praises of any of these drugs just yet. A broad class of drugs called nootropics showed potential in the 1970s, but they were “shots in the dark,” says Small, and they have since fallen out of favor with mainstream scientists. Rolipram, a drug originally intended to treat depression, works in much the same way the new phosphodiesterase inhibitors do. But its nasty side effects— patients inevitably throw up after taking it—have made it an impractical solution, and although still on the market, it is not indicated for memory boosting.
Alternative medicine has also offered remedies. Ginkgo biloba, the most well known, has been a favorite for centuries. But science has been unable to verily its effectiveness and supplements sold over the counter are often coy about their contents; even if ginkgo does work, some pill versions may not contain enough of it to have any effect The workable alternatives to alternative medicine, until now, have largely been limit ed to dozens of books containing mental gymnastics intended to keep the brains gears well greased. There’s compelling evidence for some of them, particularly crossword puzzles. Learning a new language may also be an effective memory booster. And the old saw about fish being “brain food” is also in some respects, true—a diet heavy in omega-3 fatty acids keeps blood vessels in the brain clear of blockages, allowing the nerve cells to function to the best of their abilities. But none of these remedies can completely halt “mild cognitive impairment” in adults; they can only slow it down.
Alternative remedies and brainteasers do have one advantage—they don’t raise the troubling prospect of otherwise healthy people using the drugs for a boost, like steroids for geeks. “There’s a question of whether we should he in the business of making memor boosters in the first place. Once we’re in a gray area we at least need to be careful7 says Small. “With people who are impaired by a subtle but real change in their brain function, we might not want to sit in judgment and say, ‘No, we can’t help you.’ But the fact that a high-school student can’t do well on the SAT—is that a disease?”
Ethics questions, no matter how valid, aren’t likely to keep scientists from doing the basic research that could underlie drug development. And even if that research never turns into anything in pharmaceutical form, it still holds plenty of exciting potential for those seeking to understand how memory works. Science may have made considerable progress since the ‘70s, but there is still much to he learned. Siegelbaum’s and Kandel’s labs have stumbled on to an intriguing and heretofore unknown property of ion channels, tiny protein-based structures that can transport small charged molecules across the membranes of cells. One particular type of channel is found, among other places, in the hippocampus. Lab-created mice that lack this type of channel seem to be smarter than your average mouse, especially at typical memory-based tasks like repeated mazes. The upshot: when the hippocampal channels are in use, they appear to hinder memory. It’s a startling finding that could have major implications for brain science. “Why has evolution come up with this channel and put it in this region of the brain if it impairs memory?” Sicgclhaum wonders. He suspects that neurotransmitters close the channels, rendering them moot, when the brain needs to remember something, but leave them open otherwise to screen out the ephemera of everyday life, the things that just aren’t important enough to remember long-term. (If you remember where you were when JFK was shot, your channels were probably closed at the time. If you don’t remember what you had for lunch last Wednesday, well, maybe they were closed on your lunch break.) If Siegelbaum is right, the channels offer a tantalizing possibility: what if scientists could create a drug that would close them on command, allowing for total recall? “It’s a hit of a daunting task,” says Siegelhaum. But whether there’s a pill at the end or not, it’s still great science and that’s always an audacious goal.
T HE BASIC FORMULA FOR GOOD HEALTH
IS HARDLY A SECRET: eat right and get plenty of exercise. But what does that really mean? What exactly are we supposed to eat? How much exercise are we supposed to get? Figuring out how to get into shape can be more difficult than actually doing it. Or so it must seem to the millions of normal Americans who desperately want to change their unhealthy ways, but can’t quite get started.
MAKING THE RIGHT CHOICES doesn’t have to be so daunting.
Science is giving us clues about what the body really needs, and researchers are sorting out myriad options. There’s a new food pyramid, and it provides many more details on good and bad nutrients than the old government recommendations. Some surprises: fat isn’t necessarily bad, but watch out for snack foods. Diet alone, how-ever, isn’t enough. You also need to get moving. That doesn’t mean you have to become an exercise maniac. A half hour of brisk walking a day can dramatically lower your risk of chronic disease. The payoff for all this effort is huge: a longer, healthier life.
JANUARY 20, 2003 NEWSWEEK
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