We devote this month's Nutrition Today to highlight the 2015 Dietary Guidelines Advisory Committee (DGAC) Scientific Report (2015 Advisory Report) (http://health.gov/dietaryguidelines/2015-scientific-report). This departure from our usual format carries on a tradition in this journal's 50th birthday that began with Nutrition Today's open forum when the first set of Dietary Guidelines for Americans was hatched 35 years ago. Some things never change. That first report was controversial, and parts of the DGAC 2015 Advisory Report have their advocates and critics today as well. But the past is also prologue to forging the path forward. There are more similarities than differences in the 2010 and 2015 reports, confirming the old adage that science, even nutrition science, is more evolutionary in nature than revolutionary. To get some perspective on all of this, we include a range of comments about the report from eminent nutritionists and a few choice reprints from Nutrition Today's archives.
The committee's work is done, and now it's time to thank the scientists who were on the committee for all their time and work. And it's time for the rest of us to sift through the recommendations to see what's new and where to go next. Here are some steps to take on the path:
1. Don't Let the Perfect Be the Enemy of the Good
Don't sweat the small stuff. The hundreds of comments on the Advisory Report show that good scientific minds don't always agree about some of the finer points in the report. What critics overlook is that experts virtually unanimously agree on the directions in which we should go even if the exact numbers or quantities are sometimes debated. Less calories from alcohol, fat, sugar, and salt; more whole grains; more low-fat dairy; more vegetables and fruits; and moderation in meat and poultry portions are reasonable advice. It's time to get with that program.
But let's wait for the final official 2015 Dietary Guidelines on some of the details that may need further scrutiny by federal and other scientists. The committee may sometimes have been overly generous in interpreting the limited and shaky state of science on the amounts it recommended because of lack of experimental evidence, the limitations of observational studies for causal inference, imperfect dietary assessment, and poor-quality studies and imperfect systematic reviews.1 Such problems arise with the exact amounts in targets for how little salt or how much alcohol or red/processed meat or added sugar is too much and whether lumping red and processed meat and talking about them together make sense.
Get going on the big stuff. This committee and many others before it have been criticized because most people don't eat the way the guidelines recommend.2 It's true that for most of us the guidelines remain more aspirations than actions in our everyday eating lives. We need to get started in remedying that, particularly on the major messages they convey. Two areas that deserve immediate action are maintaining or moving toward a healthier weight and decreasing our sedentary downtime while increasing our physical activity.
Get off the SoFAs: Getting off the sofa and sedentary habits is one side of the coin; the other is the SoFAs ("saturated fats and oils and added sugar") in the foods we eat. The 2010 committee took a lot of flak for its talk about energy density and SoFAs that it suggested together should account for no more than about 5% to 15% of calories per day. Because most of us get closer to 35% of calories and about 100 to 150 extra calories per day from SoFA-rich foods such as cakes, cookies, doughnuts, pies, crisps, granola bars, yeast breads, soda, energy drinks, sports drinks, and pizza, they really do need to be watched Figure 1 shows the percentage of energy intake from major food groups today.
2. Consider What's New in the 2015 Advisory Report
Sugar. One of the standout differences in the Advisory Report from earlier reports is a limit on added sugars of no more than 10% of energy intakes. The major rationale is that they are high in calories without redeeming contributions of other nutrients; the other arguments about their unique contributions other than calories to overweight, diabetes, and dental caries are not so strong. The direction is correct, but the limits are less defensible because the data are often squishy.
What about alcohol? Energy excess is truly a worry, so it is odd that alcohol, the premier "adult junk food" and a major source of empty calories in the eating patterns of adults, was not also given more attention for cutting back on calories and middle-aged spread. On any given day, a third of men and 18% of women consume calories from alcoholic beverages, and those who do get a lot of calories from that nonfood group (Figure 2)!
Cholesterol and sodium. The Advisory Report recommendations also drop the limitations of dietary cholesterol to less than 300 mg/d, but this has not been so controversial. The sodium recommendation is a little different than that in 2010 and suggests no more than 2300 mg for the general population or lower for groups at risk, and this issue remains a matter of much dispute, as the points-counterpoints in the last issue of Nutrition Today showed.
Eggs. The warnings about foods high in cholesterol, such as eggs and liver, are gone.
Caffeine. This is the first time the subject of caffeine and coffee has received attention. The evidence review concluded that moderate consumption was not associated with health risks.
Environmental influences. The report gives the role of the environment more attention than earlier reports, such as its role in the acculturation of recently arrived immigrants and the ways the built environment contributes to sedentary lifestyles
Behavior. The report also considers behavior. This theme might have been developed more if the expert on behavioral science, Dr Gary Foster, had been on the committee rather than an external expert.
Sustainability. Sustainability is the other buzzword that has evoked a lot of discussion-it is the committee's statement that eating plant-based diets is a good idea from the sustainability standpoint. Nobody can argue with that, but some have the impression that plant based means exclusively plant and no meat. Although the report does not really say this, the language needs to be cleaned up to avoid misinterpretation. And let's not pass judgment on those who choose to do their part on sustainability in other ways, such as by having one or no car or fewer children. Modifying dietary patterns is only one and not necessarily the only or the best path to sustainability. Several recent reports issued by the National Academies of Sciences are good reading on these complex issues.3-8 Sustainability in our use of natural resources should include but not be limited to food production, use, and eating patterns and be seen in the broad context. Sustainability is an issue with diet and with all of the other resources and wasting assets we use in our country and on this planet. It is a huge question and one that certainly deserves the attention of many experts. There are thorny issues here, however, involving what alterations in the agricultural system and elsewhere might be desirable, acceptable, feasible, and realistic. Perhaps next time the committee will include experts on this topic.
The enormous amount of food waste in our country is a good place to start in focusing on food sustainability, and it deserves more attention than it got in the DGAC report. For example, a recent report of the Economic Research Service of the US Department of Agriculture (USDA)9 concluded that in the United States 31%-or 133 billion pounds-of the 430 billion pounds of the available food supply at the retail and consumer levels in 2010 went uneaten. In 2010, the total amount of food loss was 1249 calories not available for human consumption of 3796 calories available per American per day. We need to get serious about this. Our country did a good job in cutting food waste in World War I and World War II (Figure 3). Minimizing waste needs to become a peacetime endeavor as well. The USDA's Food Waste Challenge is a good start (Table)
3. Act on the Nutrition Verities
Healthy weight, avoiding sedentariness, and having physically active lifestyles. Since the very beginning of the Dietary Guidelines, the basic recommendations continue to stress that we should achieve or maintain a healthy weight, stay physically active, and avoid sedentary lifestyles.
Balance, moderation, variety. The recommendations on not getting too many calories and dietary fat have not changed much, including limiting saturated fat to 10% or less, avoiding trans fat, and achieving at least 10% of calories from polyunsaturated fats. Overall fat intake gets less attention.
More plant based. The committee stresses eating a more plant-based diet, which it says should be high in whole grains, low or no fat dairy, vegetables, fruits, seafood legumes, and nuts. It provides several recommended dietary patterns (Healthy US, Mediterranean, Asian, and vegetarian). Unfortunately, the confused wording may cause some readers to misinterpret the lack of explicit mentions of foods such as lean meat, poultry, and eggs as parts of healthy patterns as deliberate slights or slams on those food groups, especially because the no-no's such as avoiding red and processed meats and limiting added sugars are repeated so many dozens of times. As the government synthesizes the final guidelines, it will help if the patterns are described more clearly in terms of the food groups and subgroups so people can get from where they are to where they might better be.
Food safety and food borne illness. Food safety is mentioned, but it would be ideal to see more of a focus on preventing food-borne illness, given the toll they take on health. Next time let's hope food safety experts are added to the Committee.
4. Stay Tuned to What's Ahead With the Official Report
Stay tuned for the 2015 Dietary Guidelines for Americans. The Advisory Report is valuable input but is not the final word on federal food and nutrition policy. The public comment period of several months for everyone who wanted to weigh in on issues discussed in the report closed in early May, after thousands of comments. Then federal experts must review the comments and the science for accuracy, review the public comments that have been made about the report, make sure the science is complete and accurate, and check to make sure that the charge they gave to the committee was met. The final Dietary Guidelines report is a policy document and not a legal document, but it affects policy and will affect regulations. For example, the Food and Drug Administration cannot approve a health claim that is inconsistent with the Dietary Guidelines, and health claims are public statements. The guidelines also affect regulatory decisions; for example, the whole-grain health claim was based in part on the 2010 report. It will come as a surprise to many to realize that dozens of experts in all the federal agencies involved with nutrition study the report and make sure that if the recommendations were implemented they would conform to current laws and regulations. The 2015 committee was not selected for expertise in government and regulatory law, so it is understandable that the report must be checked to make sure that recommendations do not go contrary to existing laws or regulations. In the 25 years since the Dietary Guidelines first saw the light of day, the vast majority of the DGAC committee's recommendations have been accepted and consistent with the wording in the initial document. However, this doesn't mean that every single thing stays the same. No committee of a dozen or so scientists can get all of the science right on every issue the guidelines address, particularly when the recommendations touch on legal issues or areas only peripheral to the committee's basic scientific expertise, such as labeling, food-borne illness, alcohol, food science, sustainability, or proposals for implementing federal regulations and programs. The committee's job is to make recommendations based on the science, not to play politics or to make policy, although most committees cannot resist suggesting their pet ideas for implementing the recommendations. In actuality, policy and program are the bailiwick of the executive branch. These are both practical considerations that must be considered. For example, it would make little sense to issue guidelines that called for more fish than can possibly be supplied.7 Finally, of course politics enters the mix as well, and every administration has its own favorite priorities. And there is a lot of noise coming from Congress and the public, and this may play a role in the final document as well, but the Dietary Guidelines process is and must remain primarily science-based policy, not politics and policy-based science, if it is to be credible and worth implementing. Later this year, federal staff must collate all the input, get the go-ahead from the Secretary of the US Department of Health and Human Services and USDA, and publish the 2015 Dietary Guidelines for Americans.
Look for MyPlate 2.0 later in 2015 or early and 2016 perhaps an updated USDA Food Pattern to translate advice into foods. Federal scientists at USDA are already busy at work figuring out how to put the recommendations of the DGAC into the MyPlate icon and eating patterns for Americans, and they may finalize it just around the time that the Dietary Guidelines come out!
5. Test Drive to Smooth the Path Forward
Do a Dietary Guidelines test drive for better execution. With the exception of holy writ, no set of recommendations is perfect, and all remain hypotheses to be tested until they are tried out in practice. Most people don't purchase a dress, a suit, or a car without trying it on. Now that the experts have spoken, it's time to put the recommendations all together and try preparing and actually eating them. Some of the patterns such as the Mediterranean pattern have been shown to work in clinical studies in other countries or decades ago, but then was then, and now is now. It's time to try them out again to find out what the barriers are to implementation in broader populations and how best to overcome them. Several years ago, government scientists at the Beltsville Human Nutrition Research Center at USDA did this with the 2010 Dietary Guidelines and found that it was possible to follow them, but hardly a piece of cake (no pun intended), involving a lot of preparation time, shopping, and planning.
Let's smooth out the kinks ahead of going prime time. For these and future guidelines, we need to find out where the kinks are and prioritize and simplify the messages. For example, food pattern modeling to meet both sodium and potassium guidelines to the letter is very difficult.10,11 How much will recommended patterns cost? The association between the cost of diets and quality indices such as the Healthy Eating Index also is a problem.12,13 It is surprising that this sort of a test drive isn't required of all of the dietary recommendations made by expert groups Public-private partnering with behavioral scientists who know what makes people tick in their food decisions and with industry that makes the food people eat may help. And if a midcourse correction is needed, we'll make them. The USDA, to its credit, is reviewing its grants program in a similar manner.14
Find ways to better translate the Dietary Guidelines into everyday eating. The 2015 report, with its emphasis on patterns, poses some real challenges in communication because for many people it means changing many things about the ways they eat simultaneously. They'll need help on priorities and simple steps that they can take to put changes into action. The same is true for the energy-output side of the equation. There are really 2 separate messages here: avoid sedentariness (no activity other than sitting or standing for most of the time you are awake) and become physically active enough to meet the physical activity goals.
Remember that eating is not a medical event-it must be enjoyable as well as healthy! The truth is we eat to live and want to live to eat, and that is fine. We just need to find ways to blend these worthy goals together without going overboard in either direction.
Expect nutrition science to change. The food and nutrition-related science field is huge; much of it is changing rapidly. Most of the recommendations haven't changed all that much, but a few have changed a lot. Scientists must keep in mind how little we know about some of the most important nutrition questions associated with eating and health and not feel betrayed when new science calls old truths into question. Science is by its nature destabilizing. As emerging science becomes settled, the Dietary Guidelines must change as well, so there is no need for apologies on that score.
Encourage excellent scientists to volunteer for DGAC 2020. The DGAC 2015 scientists have done their best to give their considered opinions on the science as they see it. They have devoted themselves to the task without being paid and in addition to their other professional responsibilities for 2 years of their lives. For all their efforts, they deserve our heartfelt thanks. It is to be hoped that soon a new group of experts can be enlisted for the 2020 guidelines process!
Look for Dietary Guidelines for 0- to 2-year-olds in 2020. The next Dietary Guidelines, in 2020, will include recommendations for infants and toddlers for the first time. Whether these will be a separate document or blended into the document for the rest of us remains undetermined but will fill a needed gap in our federal guidance to our youngest citizens. The problem is whether the enormous amount of science that must be digested will be ready in time.
6. Remember that the Dietary Guidelines have done some good
You've probably heard nutritionists gripe that practically nobody follows all of the Dietary Guidelines.2 This is no surprise; we human beings are unfaithful to recommendations that impact our health since we even skirt recommendations as important as the Ten Commandments. Actually, the truth is we Americans have come a long way toward better health since those first Dietary Guidelines in 1980. In those days, guidance was eminence based; today, it is more evidence based. The quantity, variety, quality, safety, nutrition, and cost of our food supply have never been greater. Access to food for those who are less fortunate has vastly improved, thanks to USDA's food programs. Despite an increasingly global food supply, we have made progress on food safety15 and on tracking food availability and waste.16 The 2010 report encouraging more whole grains did result in some major changes in food products, a whole-grain health claim, and more whole-grain products on the market. Sound, unbiased, and free information about eating well is on every food label, at http://nutrition.gov on every computer, and in most libraries. And most of us realize that the nutrition message is no longer simply about getting enough, but it's also about not getting too much while keeping an eye on balance, variety, moderation, reasonable cost, and enjoyment. We're still too fat and too sedentary and need to do even better, but we have made real progress in all these other ways.
Past Is Prologue
The past is prologue to the DGAC report's basic findings. No doubt it will also be so in the final official Dietary Guidelines. The tasks that remain are making sure the settled science gets acted on and that the gap between the world as we know it and a more perfect eating world we wish for is bridged not with rhetoric but with reasoned action. Only by confronting implementation problems and prioritizing the strategies for dealing with them will it be possible to develop realistic and sensible ways to go forward that make healthy eating even more of a reality.
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