Poor dietary habits (particularly low intake of nutrient-dense foods), physical inactivity, high body mass index, high fasting plasma glucose, and high blood pressure are among the leading risks attributable to morbidity and mortality in the United States, as well as worldwide, and are increasing significantly (1,2). The U.S. Centers for Disease Control and Prevention reported that 6 of 10 Americans have at least one or more chronic diseases (e.g., heart disease, cancer, and diabetes), accounting for $3.5 trillion in annual health care costs. It has been shown that a nutritious, balanced diet is one health behavior (in addition to physical activity, smoking cessation, and alcohol reduction) that can help attenuate the epidemic (3). Healthy People 2020, the nation’s health agenda, listed improving the quality of dietary nutrition as a leading goal to improving the nation’s health (4).
The diet industry is a multibillion-dollar industry because of an estimated 45 million Americans who go on a diet each year (5). The latest “best diets” rankings for 2020 conducted by U.S. News & World Report listed “best overall diets” as the Mediterranean, Flexitarian, and DASH diets, whereas other “best diets” included Ornish (heart healthy), Vegetarian (plant based), Mayo Clinic (diabetes), and Weight Watchers (commercial) among many others (6). Needless to say, there is no shortage of diets available to suit the wants and needs of the ever-expanding American population. The diet industry can be confusing and overwhelming to many Americans; therefore, it is understandable that many individuals consult with health and fitness professionals for diet and nutritional advice, recommendations, and meal planning.
The purposes of this Clinical Applications column are 1) to describe the current dietary guidelines; 2) to highlight, define, and present data specifically demonstrating the health benefits of an eating plan based on choosing plant-based whole foods; and 3) to discuss the appropriate scope of practice for health and fitness professionals regarding nutrition counseling.
Current Dietary Guidelines
The U.S. Department of Agriculture’s (USDA) 2015–2020 Dietary Guidelines for Americans recommend that individuals consume a healthy eating pattern that accounts for all foods and beverages within an appropriate calorie level (7). Specifically, a healthy eating pattern includes a variety of vegetables from all of the subgroups — dark green, red and orange, legumes (beans and peas), starchy, and other; fruits, especially whole fruits; grains, at least half of which are whole grains; fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages; a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products; and oils. In addition, a healthy eating pattern limits saturated fats and trans fats, added sugars, and sodium. The Dietary Guidelines standards for recommended dietary allowances are designed to cover the needs of more than 97% of the population to meet nutrition adequacy. With data supporting a multitude of health benefits, there is a strong emphasis to shift the American diet toward consuming more fruits and vegetables. Despite the overwhelming evidence, daily consumption continues to remain well below national recommendations (7,8).
What Is a Whole-Food, Plant-Based Diet?
Individuals often use the terms “vegetarian,” “vegan,” and “plant based” interchangeably. Although these diets do have similarities, there also are differences that make each one unique. Typically, a vegetarian diet excludes meat, poultry, game, fish, and shellfish. Some individuals following a vegetarian diet also may exclude eggs, dairy, or other animal by-products. A vegan diet typically avoids all animal and animal by-products. The term “whole-food, plant-based” (WFPB) is credited to T. Colin Campbell, a biochemist who specializes in nutrition and its correlation with disease (9). A WFPB diet is based on the following principles:
- Whole foods — foods that are not heavily processed, including whole, unrefined, or minimally refined ingredients
- Plant based — foods that come from plants and do not include animal ingredients such as dairy products, eggs, or honey
With a WFPB diet, emphasis is placed on what is put into the body over what is restricted. The intake of minimally processed whole foods such as fruits, vegetables, whole grains, legumes, nuts, and seeds is encouraged. Meat, poultry, fish, shellfish, dairy, eggs, oil, refined sugars, and refined grains may be either excluded or limited based on the preference of the individual.
WFPB Diet Research and Recommendations
Several studies have been conducted to investigate the effects of a plant-based diet on health outcomes. Published studies using the specific term “whole-food, plant-based” diets have been less common; therefore, reference will be made to research examining “plant-based diets,” which may include vegetarian and vegan diets, unless specifically stated otherwise. A plant-based diet has been noted to reduce the risk of type 2 diabetes, heart disease, certain cancers, and obesity by improving plasma lipid concentrations, blood glucose, blood pressure, body weight, and cardiovascular health (10–18). Many physicians and health associations recommend plant-based diets to their patients. For example, Tuso et al. suggest that physicians recommend a plant-based diet to all patients, particularly those with high blood pressure, diabetes, cardiovascular disease, and obesity (14). The American Association of Clinical Endocrinologists and the American College of Endocrinology on the Comprehensive Type 2 Diabetes Management Algorithm recommend that patients “strive to attain and maintain an optimal weight through a primarily plant-based meal plan high in polyunsaturated and monounsaturated fatty acids, with limited intake of saturated fatty acids and avoidance of trans fats” (19). The American Academy of Nutrition and Dietetics and the American Diabetes Association include well-planned, plant-based eating patterns (vegetarian and vegan) as a meal-planning option in their nutrition recommendations for people with diabetes (20–22). Further, a plant-based diet may work so well at improving many health outcomes that medications may need to be decreased or even discontinued entirely (14). Therefore, it is prudent for those with chronic diseases to partner with their health care provider and a registered dietitian when eating a plant-based diet.
It should be noted that plant-based diets, as with any “diet,” are not without controversy with research available to support both pros and cons. Health and fitness professionals, registered dietitians, and medical professionals must stay abreast of the current scientific evidence to provide meaningful and effective nutrition guidance.
What about the Macro- and Micronutrients?
Although eliminating animal products from the diet may potentially lead to some nutritional deficits, they can be mitigated by understanding what constitutes a nutritionally adequate diet and planning for such. A macronutrient profile of 75% to 80% of energy from carbohydrate, 10% to 15% from protein, and 10% from fat is recommended (23). Working with a registered dietitian or health care provider to create a customized eating plan may be beneficial. See Table 1 for suggestions for maximizing adequate macro- and micronutrient sources.
“What about protein?” may be the first question someone embarking on a plant-based or WFPB diet asks. This question may be particularly relevant for athletes because there tends to be a misconception that all protein comes from animals. Fortunately, there are many sources of protein within the guidelines for a plant-based or WFPB diet. A variety of plant-based foods consumed over the course of a day can provide all the essential amino acids and ensure adequate nitrogen retention and use in healthy adults. Furthermore, complementary proteins do not need to be consumed at the same meal (24). There still remains controversy as to the appropriate protein requirements for athletes versus nonathletes, as there is research to support the need for additional protein for athletes, as well as studies that suggest athletes do not require additional supplementation (25). A recent review study in athletes found no differences in physical performance between vegetarian-based diets and omnivorous mixed diets (26). Lastly, some individuals, especially teen boys and adult men, need to reduce overall intake of protein foods by decreasing intakes of meats, poultry, and eggs and increase amounts of vegetables or other underconsumed food groups (7).
Additional nutrients to consider include vitamins and minerals, particularly vitamin D, calcium, zinc, omega-3 fatty acids, iron, and vitamin B12. Vitamin D can be supplied with adequate sun exposure and intake of fortified foods. Limiting salt intake, getting adequate exercise, and not smoking are other important actions for building strong bones. Green, leafy vegetables and legumes provide iron. There are a number of plant sources of omega-3 fatty acids, as well as that found in fish. For individuals following a strict animal-free diet, vitamin B12 needs can be met by consuming fortified breakfast cereals, fortified nondairy milk, and fortified meat analogs, or with a daily multivitamin or supplement (27).
Scope of Practice
Several communications have been published lately providing excellent guidance for health and fitness professionals in regards to nutrition counseling. For example, a recent ACSM’s Health & Fitness Journal® article was dedicated to the influence of whole-food nutrition in the prevention and treatment of injury and healing from surgery. Examples of meals and foods containing macronutrients and micronutrients were given as well as the justification for employing nutrition to combat inflammation (28). Another recent article described whole-food options, as opposed to supplements, for athletes looking to gain a competitive edge (29). Both of these articles gave general advice and were written by registered dietitians. In addition, it was recommended that health and fitness professionals stay within their scope of practice when providing nutrition guidance and that the prescription of individualized diet plans be made by certified specialists in sports dietetics or registered dieticians.
A recent column discussing the legal aspects of nutrition advice provided by health and fitness professionals entitled “Scope of Practice” further elaborated the severity of violating the scope of practice (30). Caution is given for health and fitness professionals to avoid crossing into practicing in the field of a licensed health care professional, whether it be individualized medical, psychological or psychiatric (e.g., eating disorders), physical therapy (e.g., torn ligaments), or nutrition diagnoses, prescriptions, or treatment. Furthermore, the supplement industry is not regulated by the government, and claims are often based on independent rather than peer-reviewed research. Specific warning is given to health and fitness professionals conducting nutritional counseling without a valid license, as this may be in violation of state law. Providing specific meal plans as well as marketing oneself as a nutritional or dietary counselor is illegal in most states unless registered as a Licensed Dietitian/Nutritionist (LD/N), Licensed Nutrition Counselor (LNC), Registered Dietitian (RD), or Registered Dietitian Nutritionist (RDN). It is advised that health and fitness professionals align themselves with these individuals in person or even via teleconference as a referral network.
Lastly, an excellent article entitled “Crossing the Line: Understanding the Scope of Practice between Registered Dietitians and Health/Fitness Professionals,” explicitly distinguishes the scope of practice between registered dietitians and health and fitness professionals (31). The authors recommend limiting guidance to general nonmedical nutrition information as described in the Ohio Board of Dietetics (Table 2) (32).
Health and fitness professionals are uniquely positioned to collaborate with individuals who choose to adopt a WFPB diet while remaining within their scope of practice by giving general nonmedical nutrition information. Given that diets will continue to be a popular industry, it is advantageous for health and fitness professionals to stay up-to-date with the trends (and “fads”) their clients and patients are following. In addition to remaining educated through peer-reviewed, scientific literature regarding WFPB diets, health and fitness professionals also may want to consider familiarizing themselves with the nutrition focused popular, cultural, and media influences (e.g., Forks Over Knives (33), The Game Changers (34), and What the Health (35)) into which their clients and patients are exposed.
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