By Banaz Al-khalidi
First released in 1980, the Dietary Guidelines for Americans are updated and jointly published by the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (HHS) every 5 years. These guidelines provide recommendations on nutrition and physical activity for Americans aged 2 and older, and are the driving force behind Federal nutrition policies, nutrition education and food procurement programs. As such, these guidelines are used by both the public and industry, and by a wide variety of audiences including educators, health professionals and government agencies.
Earlier the 2015 Dietary Guidelines Advisory Committee (DGAC) released a Scientific Report based on the latest evidence, which will shape the finalized guidelines later this year. The committee’s work was influenced by two fundamental connections between nutrition and lifestyle-related health issues facing the U.S population:
1) Chronic diseases, overweight and obesity: about half of all American adults (~117 million) have one or more preventable chronic diseases such as type 2 diabetes, cardiovascular diseases, hypertension, and diet related cancers, and about two-thirds of adults and one-third of children are overweight or obese due to poor dietary habits and physical inactivity.
2) Food environment and settings: diet and lifestyle behaviors are strongly influenced by personal, social, organizational, and environmental context and systems. As such, the DGAC developed their recommendations based on a conceptual model of socio-ecological framework to provide recommendations at the individual, social, organizational, and environmental level.
What does the DGAC’s report say about the latest research on diet and lifestyle-related health outcomes?
The DGAC found that the current average American diet is low in vegetables, fruits, and whole grains and too high in refined grains, added sugars, saturated fat, and sodium. Furthermore, inadequate consumption of vitamin D, calcium, fiber, and potassium were categorized as nutrients of public health concern for the majority of the U.S population. Lifestyle-related health problems in the U.S. have persisted for more than 2 decades and the DGAC’s report calls for urgent preventative actions at the national, state, and local community levels. The DGAC recommended a shift in focus to a more environmentally friendly, sustainable plant-based diet that focuses on whole foods rather than specific nutrients. The overall body of evidence examined by the committee is summarized below:
“A diet higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in calories and animal based foods is more health promoting and is associated with less environmental impact than is the current U.S. diet.”
This is not to say that any food groups need to be eliminated completely to improve health and sustainability outcomes. In fact, the DGAC recommended three dietary patterns to provide options that can be adopted by the U.S. population and are also aligned with lower environmental impacts. These dietary patterns include the Healthy U.S. style Pattern, the Healthy Mediterranean style Pattern, and the Healthy Vegetarian Pattern. Furthermore, the 2015 DGAC left out cholesterol restrictions where previously, the 2010 DGAs recommended that cholesterol intake be limited to no more than 300 mg/day. The up-to-date evidence on cholesterol showed no substantial relationship between dietary consumption of cholesterol and blood cholesterol. Thus, the 2015 DGAC concluded, “Cholesterol is not a nutrient of concern for overconsumption.”
The message is clear—the 2015 DGAC recommends the U.S population consume dietary patterns that are rich in vegetables, fruits, whole grains, seafood, legumes, and nuts; moderate in low- and non-fat dairy products and alcohol; lower in red and processed meat; and low in saturated fat (less than 10% of total calories consumed per day), added sugars (maximum of 10% of total calories consumed per day), and sodium (2,300 mg per day or age-appropriate Dietary Reference Intake amount). Whether the USDA and the HHS will choose to adopt or ignore these recommendations put forth by the 2015 DGAC remains uncertain at this point. Meanwhile, dozens of health and environmental groups support the committee’s recommendations regarding sustainability, as viewed in the open letter found at My Plate My Planet, Food for a Sustainable Nation.
The advisory recommendations put forth by the 2015 DGAC are also closely aligned with recent research highlighting the urgency of shifting global diets, where healthy dietary patterns (i.e. Vegetarian, Pescetarian, and Mediterranean diets) are found to be associated with more favorable health as well as environmental outcomes. Thus, the available data strongly suggest that diets that are higher in plant-based foods will not only improve personal and public health, but also boost our planet’s health via “weight” reduction in greenhouse gases mainly due to reduction in livestock production.