Creating dietary guidelines for a diverse population is a challenge but one that is critically important to public health. In the span of 5 years since the adoption of the previous dietary guidelines, many changes have occurred, such as the advancement of research relating food intake to health outcomes, the variety and number of choices in the food supply, emerging new and popular diets and dietary patterns, as well as increased overweight, obesity, and chronic disease rates.1 In the 2010 Dietary Guidelines, there were also specific recommendations for areas needing further research.2 The 2015 Dietary Advisory Committee (DGAC) was charged with reviewing the new scientific evidence related to dietary patterns and food-based recommendations for Americans 2 years or older and with developing current recommendations to positively impact public health and wellness.3
The 2015 DGAC Executive Summary stated that 2 current fundamental realities guided their work. “First, about half of all American adults-117 million individuals—have one or more preventable, chronic diseases, and about two-thirds of U.S. adults—nearly 155 million individuals—are overweight or obese. These conditions have been highly prevalent for more than two decades. Poor dietary patterns, overconsumption of calories, and physical inactivity directly contribute to these disorders. Second, individual nutrition and physical activity behaviors and other health-related lifestyle behaviors are strongly influenced by personal, social, organizational, and environmental contexts and systems. Positive changes in individual diet and physical activity behaviors, and in the environmental contexts and systems that affect them, could substantially improve health outcomes.”4
The recommendations were divided into categories and will be discussed in the context of implications regarding cardiovascular disease (CVD) and type 2 diabetes prevention and treatment.
Dietary Patterns, Foods, Nutrients, and Health Outcomes
The DGAC found significant agreement in the current literature related to dietary patterns and health outcomes. The “healthy diet pattern” as compared with typical adult eating patterns was described as higher in vegetables, fruits, whole grains, low or nonfat dairy, seafood, legumes, and nuts; moderate in alcohol; lower in red or processed meat; and lower in sugar-sweetened foods and drinks and refined grains. This healthy diet pattern of eating was strongly associated with improved health and reduced chronic disease, including CVD and type 2 diabetes.5
A high level of fruit (recommended consumption of 1.5–2.5 cups per day) and vegetable intake (recommended consumption of 2–3.5 cups per day) was the only consistent food identified in conclusion statements as positive across all health outcomes.6,7 Higher consumption of sugar-sweetened food and beverages and refined grains was identified as detrimental to health in almost all conclusion statements, with moderate to strong evidence. They were also identified as foods with the highest contribution to energy intake or calories.8 The previous 2010 Dietary Guidelines recommendation regarding moderate alcohol consumption as a component of a healthy dietary pattern was not changed.2
These dietary pattern recommendations are consistent with the dietary recommendations of the American Institute for Cancer Research9,10 and the American Heart Association.10,11 They are also considered to be appropriate for children as well as adults. The DGAC stated that “following a dietary pattern associated with reduced risk of CVD, overweight, and obesity also will have positive health benefits beyond these categories of health outcomes.”10
Individual Diet and Physical Activity Behavior Change
The focus of this section of the DGAC report was on how to best encourage diet and physical activity behavior change to facilitate positive health outcomes. Behaviors that were mentioned include reducing screen time, reducing eating at fast-food restaurants, increasing family shared meals, self-monitoring of diet and body weight, and food labeling to target healthy food choices.12 The DGAC executive summary states that “these strategies complement comprehensive lifestyle interventions and nutrition counseling by qualified nutrition professionals.”12 Because individual behavior change does not occur in a vacuum, the social, economic, and cultural environment may improve or deter access and the ability to choose and consume the recommended dietary patterns.
Food Environment and Settings
Larger scale approaches were determined to be important in changing the food environment and impacting foods available and accessible to individuals. Examples included federal nutrition assistance programs such as Women, Infants, and Children and the Supplemental Nutrition Assistance Program, which provide and support access to affordable healthy foods. The DGAC also identified other evidence-based diet-related approaches and policies that have positively impacted obesity and diet-related chronic diseases.
The evidence generated and reported from multicomponent prevention programs in child care settings, schools, and worksites suggests that they are promising in improving weight-related outcomes.13 School and worksite policies were associated with evidence of improved dietary intake.13 Multicomponent school and work site programs also resulted in increased fruit and vegetable consumption.13 Other approaches such as “procurement of healthy and affordable foods and beverages and reduced access to energy-dense, nutrient poor foods and beverages” lacked adequate evaluation evidence at this time.13 The committee recommended collaborative partnerships and restructuring the environment to facilitate healthy eating choices and physical activity especially in high-risk groups such as low-income or minority populations.13
The 2015 DGAC report was the first time food sustainability and safety were addressed in the dietary guidelines. A sustainable diet was defined as higher in plant-based foods, including vegetables, fruits, whole grains, legumes, nuts, and seeds and lower in calories and animal-based foods.14 This diet pattern was described as healthier and producing less negative environmental impact, including land use, water use, energy use, and greenhouse gas emission, than the current US diet does.14 The Healthy Mediterranean Diet Pattern and the Healthy Vegetarian Pattern were also noted as providing similar benefits.14
An 8-oz portion of seafood a week was also described as an important part of 2 of the 3 healthy and sustainable dietary patterns.15 The DGAC reported that in their review of the evidence, farm-raised seafood had as much or more eicosapentaenoic acid and docosahexaenoic acid per serving as wild-caught seafood does and farm-raised seafood will contribute to expanded supply of seafood both nationally and internationally.14
The DGAC indicated that there was strong evidence that coffee consumption up to 400 mg of caffeine was not associated with health risk in healthy people and that there was consistent evidence that coffee consumption was associated with lower risk of type 2 diabetes and CVD in adults. Because many people add sugar, cream, or milk to coffee, the DGAC recommended minimizing calories from added sugars and high-fat dairy or dairy substitutes. In addition, the committee reviewed what was described as limited data suggesting adverse health outcomes such as cardiovascular events and caffeine toxicity linked to consumption of large energy drinks containing caffeine. However, limited or no high-caffeine drinks or other products were advised for children and adolescents and no consumption of high-caffeine energy drinks and alcohol together was advised.16
Following a review of current evidence, the food additive aspartame seemed to be safe. The DGAC also updated its guidelines for safe food handling at home.16
Crosscutting Topics of Public Health Importance
Because previous dietary guidelines made recommendations on sodium, saturated fat, and added sugars, the evidence on those topics was reviewed by the 2015 DGAC. Consumption of a healthy diet low in saturated fat (<10% of total calories), low in added sugar (<10% of total calories), and low in sodium (<2300 mg/d) was recommended.17 Added sugar in the diet should be reduced and not replaced by low-calorie sweeteners. Healthy replacements included herbs and spices for sodium, water in place of sugar-sweetened beverages, and unsaturated fat including polyunsaturated fat and monounsaturated fat instead of saturated fat. Labeling and reformulation of food items were encouraged so that consumers can compare products and thereby reduce intake of sodium, saturated fat, and sugar. The DGAC also determined there was strong evidence of the benefits of physical activity for both health promotion and chronic disease prevention.17
Implications for Cardiovascular Disease Prevention and Treatment and Diabetes Prevention and Treatment
Although the 2015 DGAC recommends that Americans eat a healthy diet, which they have carefully defined based on current evidence, some of the current recommendations differ from what had previously been recommended related to CVD and diabetes prevention and treatment. Specifically, no recommendation related to cholesterol or total fat was present in this report but rather replacement of saturated fat with unsaturated fats (polyunsaturated fat and monounsaturated fat) to achieve no more than 10% of total calories from saturated fat.
Previously, the 2010 Dietary Guidelines for Americans had recommended that dietary cholesterol intake should be limited to no more than 300 mg/d. The 2015 DGAC discontinued this recommendation because available evidence showed no appreciable relationship between consumption of dietary cholesterol and serum cholesterol. Cholesterol is therefore not a nutrient of concern for overconsumption in this report.18
A reduction in the intake of added sugars to less than 10% of total calories was determined important to improve the health of Americans. The DGAC stated that the reviewed research provides clear evidence that “persistent, prevalent, preventable health problems notably overweight and obesity, CVD, type 2 diabetes and certain cancers have adversely affected the health of the U.S. public for decades and raise the urgency for immediate attention and bold action.” They recommend establishment of a “culture of health” where healthy lifestyle choices become easy, accessible, affordable, and normative.
The clinical and public health implications for nurses and healthcare professionals are vast and varied. Taken together, the guideline-based recommendations suggest new opportunities for leadership roles in prevention of CVD and chronic conditions, including advocacy for policies that will improve the food (and physical activity) environments for diverse populations and encouraging uptake by healthcare providers, patients, and systems of healthcare. Given the complexity of dietary behavior change, consumers will need access to evidence-based educational resources and intervention programs and services in public health and healthcare settings to facilitate adoption and maintenance of healthy dietary behaviors. Our leadership role includes communicating to clients and patients the importance of behavior change, setting standards for healthy dietary patterns in various settings including prevention services in our healthcare and public health systems, and helping patients/clients access evidence-based and effective nutrition and comprehensive lifestyle services and programs.
The author appreciates the careful review of the Progress in Prevention Column Editors: Jane Nelson Worel MS, RN, APN-BC, FAHA, FPCNA, nurse practitioner, Phases Primary Care for Women, Madison, Wisconsin, and Laura L. Hayman, PhD, RN, FAAN, FAHA, associate vice-provost for research and professor of nursing, College of Nursing and Health Sciences, University of Massachusetts Boston.