Four Doctors Face Off on our Most Pressing Nutrition Issues
The nutrition headlines from the past year have all the plot twists and turns of a Christopher Nolan film: The good guys are now the bad guys, the old standbys are not to be trusted, and the accursed have been vindicated.
Two significant studies this past year threw into serious doubt everything we thought we knew about what is “good” or “bad” for us. A University of Cambridge study raised questions about the link between saturated fats and heart disease—as well as the nutritional guidelines that have long advised us to restrict their consumption. In this meta-analysis of 72 unique studies, researchers found that total saturated fatty acid as a biomarker was not associated with coronary heart disease risk. In another study, sugar (more specifically fructose, a derivative of sugar featured prominently in many processed foods) took another hit when researchers at Boston’s Beth Israel Deaconess Medical Center found more evidence of its links to disease promotion and metabolism destruction.
Thirty years ago, the science indicated we should bar saturated fats from our diets—leaving the back door open to sugar, which snuck in with nearly every new low-fat product to hit the grocery. Now many physicians see the fat-free craze as a blunder that escalated the nation’s obesity epidemic and its ensuing spectrum of related diseases (heart disease, diabetes, cancer). Such sudden shifts, however, make most consumers uneasy. Can we trust the new science? Should we? Here to help set the record straight are four authorities on diet and nutrition: Richard Carmona, MD, the 17th U.S. Surgeon General; Joel Fuhrman, MD, author of The End of Dieting; Robert Lustig, MD, professor of clinical pediatrics at the University of California, San Francisco and author of Fat Chance; and Pamela Peeke, MD, an expert on food addictions and most recently the author of The Hunger Fix.
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Sugar is the nutritional devil du jour. Just how bad is it for us?
Dr. Richard Carmona: Science evolves all the time—the things we thought were dogma 20 years ago, such as trying to eliminate all fat from the diet, we later discovered were not really the issue. We created policies based on that science. Now we know that sugar is a substance you can be more or less addicted to. Sugar is an energy source. In excess you will store it and get fat. But it isn’t like we can eliminate all sugar from our diets. If we do not take in enough sugar, we’ll break down proteins in our own body to do it. A little sugar is OK, but you do not want a lot.
Dr. Pamela Peeke: I don’t demonize anything. I don’t go to a moral place about this. Clearly, we have had sweet in our diets since the Paleolithic era, but we got it from different places—you pulled a blueberry from a bush, for instance. And that sweetness matters because it is rewarding. If food is not rewarding, we won’t eat it. The issue is not sugar itself, but the source of that sweetness. We have so much science that says the reward center of the brain has been spun into overdrive with refined and processed hyperpalatables—sugar, salt, and fat. Chief among them is sugar, which is as addictive as cocaine or morphine. Not everyone is addicted to sugar, but the epidemiologic data says that one in five people are. That means if you have the genetics (addiction) and epigenetics (lifestyle choices and environment) that set you up to be vulnerable, it is not about portion anymore. Instead it is about the quality of food products and their influence on the brain and body.
Dr. Joel Fuhrman: That’s true. Processed foods are addicting, and reducing sugar is not enough because moderation does not work with addictive substances. All sugar isn’t bad, or we would have to remove fruit from our diet. Fruit has pectin and fibers and beneficial compensatory nutrients. But when you have too much concentrated sugar removed from the natural package it came in, it promotes disease. For most people, moderate changes are doomed to failure. It doesn’t work for smokers or alcoholics, and it won’t work with sugar for many people.
Dr. Robert Lustig: Everybody likes to say that “sugar is poison,” but here’s the truth: Fructose is a dose-dependent liver toxin, and we are over our threshold. One ice cream soda will not kill you—but 10,000 might. The causation has been proven. Can you think of another dose-dependent liver toxin? Alcohol. Sugar and alcohol are metabolized the same way in the liver and cause the same diseases: diabetes, metabolic syndrome, fatty liver disease. Sugar is also the marker for processed food: Of the 600,000 items in the average American grocery store, 77 percent are spiked with added sugar. Of all the things wrong with the Western diet, sugar is the most actionable, because it is what the food industry specifically uses to get you to buy more.
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Where does that leave fat?
PEEKE: Healthy fat is incredibly important to the diet. It isn’t about fat or no fat. The quality is the real issue here. Natural sources of fat support our health and well-being. Science now shows that the “fat free” era was misguided. Instead, we now appreciate that we need to integrate healthy fat into our diet to improve satiety, provide fuel, and promote optimal cellular repair.
CARMONA: You need fats. You cannot make cells without them, but you want good fats. Fat molecules are the precursors for cell messengers, the things that mediate lung disease and inflammation. If you are eating bad fats, you are fueling a pathway that causes inflammation.
FUHRMAN: It is not the fat that is good or bad; it is the food that houses the fat that is good or bad. We need fat for good health, for absorption of nutrients, and a certain amount is required for hormonal production and healthy cells. Fat is critical for heart, brain, and nervous system function. But when we extract fat from the food and try to call it good or bad, we miss the whole point, because now it no longer accompanies the health-supporting nutrients from the whole food.
LUSTIG: The fat hypothesis 30 years ago was based on faulty science. The new research is debunking the old dogma. When the Nutrition Committee of the American Heart Association says that they got it wrong, you know that something is up. Here’s what you need to know: There are seven classes of fats, some of which will save your life, and some of which will kill you: Omega-3s are the healthiest oils; they are anti-inflammatory and have been shown to prevent dementia. Monounsaturated fats help you metabolize lipids faster, which is good. Polyunsaturated fats provide the mitochondria of your cells with fatty acids that can support efficiency—unless you heat them too high, which turns them into trans fats. Then, we have medium-chain triglycerides, which can drive liver fat accumulation, the hallmark of metabolic syndrome. Omega-6s promote inflammation, and trans fats are the devil incarnate. The bacteria in food can’t digest it, and we can’t either, so it lines our livers and arteries and kills us.
What is the best source of dietary fat?
PEEKE: The higher the quality, the better—and by that I mean the least processed. Bring on the almonds, the avocado, and the olive oil.
FUHRMAN: The best source of dietary fats are nuts and seeds, which are absorbed slowly and have all kinds of nutrients, antioxidants, and polyphenols important for good health. But not oils. There is no such thing as a healthy oil, because in the process of making it, you discard the beneficial parts and turn oil into a low-nutrient source of calories that are quickly absorbed and easily stored as body fat. I’m not saying a little olive oil is dangerous; I use some on my broccoli. But if you’re overweight, you shouldn’t be pouring extra calories over your food.
LUSTIG: Oil is unhealthy? That’s ridiculous. And it’s wrong. I disagree with blanket statements like that. Olive oil is fine, as is avocado oil and sesame oil. Soybean, corn oil—not so good. Canola is a mixed bag, not great.
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What about saturated fats?
LUSTIG: Saturated fats are neither good nor bad. There are two classes: animal saturated fats, or even-chain fats, which might predispose you to diabetes; and dairy saturated fats, or odd-chain, which, according to at least one study, may prevent diabetes. So saturated fat isn’t just saturated fat; its benefits or detriments depend on its origin.
FUHRMAN: We have the same problem with saturated fats as we do with sugar: We eat too many animal products, which have been linked to an increased risk for certain cancers. Watch—we’ll cut out sugar, replace it with something worse, and then you’ll be hearing sugar is back. It’s crazy. The point is we have to eat more plant produce and fewer processed foods and animal products.
Is there a consensus about animal products—specifically protein?
FUHRMAN: We consume 25 to 30 percent of our diet from animal products. The studies show that at that level of animal product consumption you have 75 percent increased risk of overall mortality, and a 400 percent increase of cancer in the 50 to 65 age range.
Many “paleo” adherents recommend far more than 30 percent, which is crazy. Meat in excess, just like sugar, promotes high rates of heart disease. Excess animal products promote IGF1, which stands for insulin-like growth factor, an anabolic hormone, high levels of which promote fat storage, aging, heart disease, cancer, and are linked to high rates of breast and colon cancer, heart attacks, and dementia. We should likely be consuming less than 10 percent.
LUSTIG: I disagree—the problem is not with the animal; it is how that animal was fed. Corn-fed animal meat is very high in inflammatory omega-6s and branch-chain amino acids, which increase liver fat accumulation. Meat sold in supermarkets in this country is marbled with fat—and that’s used as a selling point. Know what that fat is? It’s muscle insulin resistance. That’s metabolic syndrome. By feeding them corn, the animals get fatter faster, which turns a bigger profit, and gives the animal muscle insulin resistance. Argentina has the best beef in the world. Those cows graze on grass in the Mendoza Valley. I’ve been to butcher shops there. The meat is lean and pink and consistent throughout. It’s a dietary staple, and the people there are doing fine. So to say animal protein is bad is untrue. It’s what we do to the animal that’s terrible.
Is there an ideal dietary balance between fats, carbohydrates, and protein?
PEEKE: For optimum weight, health, and longevity, I recommend 30 to 35 percent each of protein and fat, which is incredibly satiating and cuts carb cravings. (That is higher than what was recommended in the past, which was closer to 15 percent protein and 20 percent fat.) That leaves you with around 30 percent carbs, which should be mostly veggies, a smattering of grains, and some fruit. Eating five or more vegetables and two fruits daily reduces your risk of death by 42 percent, compared to those who eat less than one serving per day. Just having one serving of fresh vegetables reduces your risk of death by 16 percent. But you must have a combination of healthy fats, proteins, and carbs. You can’t just be buried in arugula. And no one dropped dead overnight because they had bacon with their eggs on a Sunday.
FUHRMAN: I think you are asking the wrong question—and perpetuating the problem. It’s wrong to make a separation between fats, carbs, and protein. We should instead be talking about low-quality versus high-quality food, and asking which foods have the most phytonutrients and antioxidants, which ones slow the insulin response versus flood the body with calories. A nutrient-dense diet slows down the aging process, repairs cells, and reduces inflammation. We need more whole plant–derived fats, carbs, and proteins.
CARMONA: My philosophy is generally everything in moderation, not deprivation. We don’t expect austerity. If you are eating every day until you’re full, you’re in trouble. Eat just before you are full, maybe three-quarters of what you have on the plate. Let that be your guide. Is it OK if you have ice cream or a Coke once in a while? Well, sure. But if every day your diet is something that we can all agree is not optimal, you pay the price. Food is an epigenetic input—you send information to your genome that can alter DNA and increase the risk for heart disease or cancer. And obesity carries a higher risk of cancer. These dots are connected.
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Gluten is another vilified substance. Are there any weight-loss benefits to going gluten-free?
PEEKE: If you think that by going gluten-free you will suddenly find nirvana in weight loss, you are in for an unpleasant surprise. Unless diagnosed with Celiac disease, a serious autoimmune disorder affecting one to two percent of the population, or you are gluten-sensitive, going gluten-free will not help you lose weight. Gluten-free products are enjoying a health halo effect that they have not earned.
CARMONA: Some claim that if you have less gluten you feel lighter, but that is subjective. Many gluten-free products have more sugar and salt. You have to ask yourself what are you eating that is causing you to gain weight, rather than focus on gluten as the culprit.
FUHRMAN: Many proponents of a gluten-free diet claim gluten is bad for everybody, painting all whole grains with a negative broad brush. Of course, there is a percentage of the population intolerant to gluten, but the generalization that it’s bad for everyone does not hold up to scientific scrutiny.
How important or even relevant is calorie counting?
CARMONA: The calorie is just a measure of energy and heat. When I went to med school, we were told if you take on too much of the energy sources, you will store it and gain weight. But there is a difference between healthy calories and non-nutritive calories.
PEEKE: The problem with calorie counting is that it takes you out of the equation and makes eating a numbers game. If you are dissociated from your body, you can’t tell if you are full or not, so you get hung up on calories instead of tuning in to what your body needs. Understanding what a calorie is and the number of calories associated with foods you tend to eat is helpful, but don’t obsess about the numbers.
LUSTIG: Calories make sense when you talk about calories out. A calorie burned while sleeping is the same as a calorie burned while exercising. But calories in are a different matter. Where those calories come from determines where they go. Absorption, metabolism, and insulin response determine whether a given calorie might lead to problems.
FUHRMAN: I don’t recommend counting calories, but that doesn’t mean calories are not something to worry about; they are just not the main thing. The secret to living well is not how much you eat, but what you eat. To be healthy and slim, eat more high-nutrient plants and less of everything else. It’s called “crowding out”—the more plants you eat, the fewer processed foods you will desire.
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What are the biggest obstacles to better health in this country?
FUHRMAN: Dietary ignorance, personal bias, and misinformation. We are a nation of food addicts committing suicide with food. People are so addicted to refined foods that they will look for reasons to keep eating it. And yet, people who improve their diets end up enjoying their new diet as much as they did the old one. It is a myth that you have to give up pleasure to eat healthfully. But change causes anxiety, and so people avoid it. If people knew they could extend their lives by 15 to 20 years and wouldn’t have to have heart attacks or strokes or suffer dementia, they would change. We could win the war against cancer with excellent nutrition.
LUSTIG: The truth is, Dr. Fuhrman’s diet works—he has plenty of data that show he can reverse telomere shortening and cardiovascular plaques. But I don’t subscribe to it because it tastes horrible and, like a low-carb diet, it has very limited options. I believe one of the biggest obstacles to better health is the persistent belief that what we consume is completely attributable to personal responsibility. I’m not saying there is no such thing as personal responsibility. But the food industry refuses to accept any. Corporations are behaving the way they did with tobacco, giving consumers the power to choose and then seeking cover from any responsibility behind it. The food industry makes money hand over fist from corn, wheat, soy, and sugar. The problem is that every one of those commodities is driving chronic metabolic disease.
CARMONA: As surgeon general, my greatest plague was not avian flu, it was politics. The issues around food, subsidies, and special interest groups are so politicized that we can’t have rational discussions. Take, for instance, the farm bill. My thought was, what if we subsidized farmers to grow healthy crops? But it was a third-rail issue, because if a politician lived in the areas where the subsidies were being given and took that on as a cause, he probably would not be re-elected. The farmers and special interest groups are so entrenched, no one wants to take on the issue. Plenty of smart people flank both sides of the aisle, but no one is willing to cross that line, when the answer lies in the middle. Americans no longer trust the direction the government provides because it is seen as partisan. Politics keeps us from moving policy and legislation, and the public suffers as a result. An inability to promulgate effective policy has led to high morbidity. As the comic strip character Pogo said, we have met the enemy, and he is us.
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Richard Carmona, MD, MPH, FACS is the 17th surgeon general of the United States, serving from 2002 to 2006. He is president of the board of directors at the Canyon Ranch Institute, a non-profit public charity dedicated to creating optimal health for all people through education, and a distinguished professor at the University of Arizona. He was nominated by President George W. Bush in 2002 to surgeon general, based on his experience in public health, clinical sciences, healthcare management, and preparedness, and his commitment to prevention as an effective means to improve public health and reduce healthcare costs while improving the quality and quantity of life.
Joel Fuhrman, MD is a family physician and the author of five New York Times bestsellers, including his most recent, The End of Dieting. His plant-focused diet has drawn a considerable amount of attention and interest by scientists and fans the world over,and he created the Aggregate Nutrient Density Index scoring system, adopted by Whole Foods Market, which rates foods on a scale from 1 to 1,000 based on nutrient content. Dr. Fuhrman, who is also the research director of the Nutritional Research Foundation, is a former world-class figure skater, and he has advised professional and Olympic athletes on maximizing performance and preventing injury.
Robert Lustig, MD is a neuroendocrinologist and a professor ofclinical pediatrics at the University of California, San Francisco (UCSF). His most recent book is Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease. His online lecture, “Sugar: The Bitter Truth,” has garnered more than five million hits to date. As the director of the Weight Assessment for Teen & Child Health (WATCH) program at UCSF, he has a particular interest in the biochemical, neural, hormonal, and genetic influences in the expression of the current obesity epidemic both in children and adults. A graduate of MIT and Weill Cornell Medical College, Dr. Lustig has published more than 85 research articles.
Pamela Peeke, MD is an internist who specializes in integrativemedicine, an assistant clinical professor of medicine at the University of Maryland School of Medicine, and a fellow of the American College of Physicians. In 2012, she published the New York Times bestseller The Hunger Fix: The Three-Stage Detox and Recovery Plan for Overeating and Food Addiction. Dr. Peeke is WebMD’s lifestyle expert and serves as chief medical correspondent for nutrition and fitness at Discovery Fit & Health TV. Presently she is the senior science advisor to Elements Behavioral Health, a network of residential addiction treatment centers, where she is creating a national program for the treatment of food addiction.