Clinical nutrition researchers have generated tomes of contradictory advice for healthful eating.
The U.S. government has just served up a heaping mouthful to people who eat — the Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010.
It not only squarely addresses the undeniable — that two-thirds of American adults are either overweight or obese and that our children are on a similar trajectory — it also recasts some advice we have heard before: urging Americans, for instance, to shift their diets away from meat and animal protein and fats — foods such as red meat, cheese and butter — toward a more “plant-based diet,” a term that includes not just fresh fruits and vegetables but also foods such as nuts and lentils and olive or canola oil.
Then the report goes further. It recommends that we slash our salt intake by almost a third. It makes clear that people put their health at risk when they, on a weekly basis, do less than 2.5 hours of moderate physical activity or 75 minutes of high-intensity exercise. And it discusses at length the social and economic forces at work that have made good diets and adequate exercise easy for Americans to achieve.
The report — 677 pages long and two years in the drafting — is the first step in the federal government’s effort to (again) shape what, and how, Americans should eat to optimize their well-being. It has embarked on this effort every five years since 1980.
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The bland title belies a history of controversy. In the last two decades, clinical nutrition researchers have generated tomes of maddeningly contradictory advice for healthful eating. At the same time, nutrition watchdogs have charged that the food and restaurant industries and American farmers — in short, sectors with powerful financial interests at stake — have effectively hijacked the dietary guidelines.
Meanwhile, Americans have grown fatter and sicker.
With its latest report, an advisory panel of 13 independent experts in health and nutrition has tried to (again) lay to rest these controversies and lay the groundwork for dietary guidelines based on research evidence.
Released June 15, the report (available online at www.cnpp.usda.gov) will be open for public comment until July 15. It’s a joint product of the U.S. Department of Agriculture and the U.S. Department of Health and Human Services.
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WHAT THE EXPERTS SAY ABOUT THE DIETARY GUIDELINES REPORT
Some see sound advice and applaud the suggestions for a more plant-based diet. But others say the new guidelines can be confusing or don’t go far enough in combating obesity.
MARGO WOOTAN, director of nutrition policy, Center for Science in the Public Interest (Washington)
The dietary guidelines provide sound advice for the majority of Americans. Basic nutrition advice hasn’t changed much over the 30 years that the dietary guidelines for Americans has been published. It has long advised people to eat less unhealthy fats, salt and added sugars and more fruits, vegetables and whole grains — and, for the most part, that advice has been ignored by individuals and institutions.
The new Dietary Guidelines Advisory Committee report, at long last, recognizes that what is most needed is an unprecedented effort to help people follow the dietary guidelines, including changes in policy and the food environment. The report wisely recommends that USDA and HHS develop a national strategy to help people eat better, including ramping up nutrition education, expanding access to fruits and vegetables, and getting industry to provide more healthful products.
The refinement of the advice to reduce unhealthy fat intake is a good step toward better health; i.e., limiting saturated fat intake to less than 7 percent of total calories and avoiding artificial trans fat. But I do think the advice to limit cholesterol-raising fats (saturated fats exclusive of stearate and trans fat) to less than 5 percent to 7 percent of energy is misguided. Stearate may not raise cholesterol levels, but it is still not clear whether it contributes to heart disease in other ways. The advice is too complicated, and impossible for people to follow, since stearate is not listed on food labels.
DONALD HENSRUD, medical editor-in-chief, “The Mayo Clinic Diet,” The Mayo Clinic (Rochester, Minn.)
In the past, the dietary guidelines were for “all healthy Americans.” That didn’t place enough emphasis on the increase in the prevalence of overweight and obesity over the past few decades, along with other chronic diseases related to diet, nutrition and physical activity.
Currently 1 in 3 adult Americans is obese and 2 in 3 are overweight or obese. These guidelines have been updated to provide the strongest recommendations to date from the dietary guidelines to help Americans deal with this significant public health problem. They have expanded their recommendations to include the best dietary advice to help prevent and treat cardiovascular disease and Type 2 diabetes mellitus, and also include broadened recommendations for children.
They have also added chapters on the total diet and practical recommendations for people to follow, and on the environmental and societal aspects of implementing the guidelines, both of which are very important.
They summarize four major findings that are very appropriate (reduce obesity, increase plant-based foods, decrease sugar and solid fats, and increase physical activity). But there is so much information here, it is challenging to summarize these recommendations into easy-to-understand distinct points, so it will be challenging for most people to read and understand. The final document is extremely comprehensive, well thought out, up to date and practical. Whether this will change the way Americans eat will depend on other aspects of implementation.
DR. WALTER C. WILLETT, chairman of the Department of Nutrition, Harvard School of Public Health (Boston), Author, “Eat, Drink and Be Healthy”
Positive changes include a more explicit and stronger recommendation to reduce consumption of sugary beverages, a greater emphasis on reduction of sodium and much less emphasis on the percentage of calories from fat.
Shortcomings of the report include:
The percentage of total fat is still recommended to be less than 35 percent of calories. The advisory panel apparently adopted this recommendation to stay consistent with another set of guidelines — the Institute of Medicine’s Daily Recommended Intake levels. But the Institute of Medicine’s recommendation is entirely related to weight control, and it’s out of date. The best available evidence demonstrates that percent of calories from fat in a diet has no bearing on weight loss — a point the dietary guidelines committee acknowledges. It makes no sense to base the dietary guidelines on an outdated recommendation.
Also, the recommendation for three servings of milk per day is not justified and is likely to cause harm to some people. The primary justification is bone health and reduction of fractures. However, prospective studies and randomized trials have consistently shown no relation between milk intake and risk of fractures. On the other hand, many studies have shown a relation between high milk intake and risk of fatal or metastatic prostate cancer, and this can be explained by the fact that milk intake increases blood levels of IGF-1, a growth-promoting hormone. The justification for drinking three glasses of milk per day on the basis of increasing potassium intake is also not valid as the extra calories, even with low-fat milk, would easily counterbalance the benefit of the extra potassium.
The recommendation for high intake of lean meat is based on the large amount of heme iron in meat and the high prevalence of iron deficiency in premenopausal women, due to regular menstrual losses. (Heme iron, plentiful in meat and fish, is more readily absorbed by the body than non-heme iron, a chemically distinct form of iron found in lentils, beans and enriched grains.) But this recommendation is worrisome, as there is substantial evidence that high intake of heme iron may increase risks of diabetes, and there is also some evidence that red meat may increase risk of premenopausal breast cancer. The report seems notably silent on vitamin D, even though there is strong evidence that blood levels are not optimal for two-thirds of Americans. I wonder if this is related to the almost religiously anti-supplement tone of the report and that supplementation with vitamin D is probably the safest way to increase levels.
The report still condones half of grains from refined grains. Refined grains have adverse metabolic effects, many empty calories and no benefits. Thus, this is a major part of the U.S. diet that should be reduced as much as possible.
MARLENE SCHWARTZ, deputy director, Rudd Center for Food Policy and Obesity, Yale University (New Haven, Conn.)
They acknowledged several things that I had not seen before. First, there was a clear acknowledgment that obesity and overweight are major health problems among Americans. Second, they identified elements of the environment that promote poor nutrition. Finally, they noted that to change the American diet, we need a change in the whole food system — not just a greater emphasis on personal responsibility.
My favorite sentence was from the conclusion of the executive summary, where they encourage all stakeholders to help “make every choice available to Americans a healthy choice.” So often, people who sell unhealthy foods say that they are only “providing choices,” as if promoting foods high in sugar, salt and fat is some type of patriotic gesture. Choice does not have to be choosing between apple slices and French fries; it could be choosing among apples, oranges and pears. I would be thrilled if we could get to the point where people realize that an array of healthy, delicious foods still provides choices.
I was also very pleased to see the guidelines name specific types of foods as foods that we need to limit. The label SoFAS (shorthand for solid fats and added sugars) will be useful if people can really understand what it means. Last time, the USDA talked about “discretionary calories,” which seem to now be called SoFAS. I never felt that the American public figured out what discretionary calories were and how few they were supposed to eat in a day. My worry with SoFAS is that foods don’t come labeled with their calories from SoFAS specified. So, some foods are all SoFAS (candy, cake, sugar sweetened beverages and butter), but most SoFAS are consumed along with other types of calories (like pizza, high-fat cheeses), so it will be hard for people to know how many SoFAS calories they have used up. I would like to see some educational materials that show exactly where these calories come from and how few you can consume within a day and still stay within these guidelines.
DR. DEAN ORNISH, president, The Preventive Medicine Research Institute (Sausalito, Calif.)
This report is an improvement over the previous guidelines. There seems to be a convergence about what constitutes a healthy way of eating for most people that is reflected in the new dietary guidelines. That’s encouraging. There’s a growing awareness that a healthy diet is plant-based, low in red meat and higher in seafood; low in refined carbohydrates, such as refined sugar and white flour; lower in sodium, trans fats, saturated fat and processed foods; and higher in unrefined carbohydrates, such as whole grains, fruits and vegetables in natural forms.
Although it recommends seafood in general, it doesn’t distinguish between types of seafood in particular. For example, it would have been helpful to distinguish between seafood such as salmon that is rich in beneficial omega-3 fatty acids from seafood such as tuna and swordfish that is higher in harmful mercury.
Finally, it would have been helpful to discuss more fully that what we include in our diet is as important as what we exclude. There are literally hundreds of thousands of protective substances that are found primarily in fruits, vegetables, whole grains, legumes and soy products. Instead of thinking about diet primarily in terms of reducing risk of illness and premature death, I find it much more useful to talk about how much better you look and feel when you eat and live more healthfully. Joy of living is much more sustainable than fear of dying.
DR. RICHARD DECKELBAUM. director, Institute of Human Nutrition, Columbia University (New York City)
I’m very impressed by the guidelines. These recommendations are definitely going to be right for most Americans.
They have changed in useful ways. The advisory committee has done a huge and comprehensive job in evaluating the strength of the evidence across the field of nutrition. Where the evidence is not clear, they say so.
They’ve also done a good job by bringing other sectors into the process — business, agriculture, aquaculture. That approach really conveys an important message: that you can’t solve the obesity crisis singly; everyone has got to be involved.
The questions the advisory committee puts forth are questions that many people have — not just the public but health practitioners and nutritionists. I found the answers were very helpful.
The sections on fatty acids and cholesterol are a marked advance over past advisory committee reports, though we still don’t know what the exact recommendations are going to look like. The section on omega-3 fatty acids is stronger and better and handles questions of toxicity and fear of mercury poisoning: It says the benefits of eating fish far outweigh the risks and gives specific recommendation for omega-3 intake per day.
They also put the issues of glycemic load and glycemic index into a real-life perspective, and they do explore the potential relationship of the recommendation to metabolic syndrome or diabetes.
ALICE LICHTENSTEIN, director, Cardiovascular Nutrition Lab, Tufts University School of Medicine (Medford, Mass.)
Having served in the drafting of the 2000 Dietary Guidelines for Americans, I don’t think we’re seeing a radical shift in what has been proposed. What we are seeing is a strengthening of some of the recommendations and more specificity in others. The proposal to shift toward a dietary pattern containing plant-based foods represents an actionable way to comply with earlier versions of the guidelines that emphasized limiting intakes of animal fats.
From the perspective of Americans adhering to the dietary guidelines, the more concrete the advice is, the better. This report makes what we should do more explicit, which I think is going to be particularly helpful. From the perspective of controlling calorie intake, which the majority of Americans needs to do, the report emphasizes substituting better choices within categories. For example, in choosing a dietary fat, say, to put on vegetables, it’s better to use this than that.
The report also focuses on what should be reduced in the diet: sugar, solid fats, sodium and refined grains. Again, these are not new concepts, but as a population we have not been particularly successful in achieving them. The report puts considerable emphasis on these components of the diet.
Regardless of diet quality, the most critical issue for Americans is body weight. Even an ideal diet in excess of caloric needs is going to result in weight gain. That is, too much of a good thing can also be bad, and that’s a concept that can get lost in translation. We need to talk about what foods should displace other foods, not that you should be adding whole wheat muffins to what you’re already eating in the morning.
DR. FRANCINE KAUFMAN, director, Center for Diabetes, Endocrinology & Metabolism, Childrens Hospital Los Angeles, Author, “Diabesity”
The guidelines continue to improve — this year is another leap forward.
The guidelines cover the life span, and stress important aspects of weight and nutrition during pregnancy — excessive maternal weight is a huge risk factor for childhood obesity and risk of diabetes. Childhood nutrition and elder nutrition are also covered. There is adequate emphasis on reducing common disease risk. The guidelines continue to improve in recommendations concerning nutrient-dense, less calorie-dense items. They do hit all of the important nutrition concepts relevant to the overall populace. Energy balance is key in this document, with adequate stress placed on increasing physical activity.
The main shortcoming I see is not tackling the federal food programs: school lunch, food stamps, WIC (Women, Infants and Children). The guidelines need to demand that these programs get in line with the recommendations.