Plant-Based Eating

Plant-based eating is a dietary plan that incorporates whole, unrefined plant-based foods and plant proteins into the daily diet as the primary source of nutrition. Although the focus in plant-based eating is to consume foods primarily from plant sources, appropriate dairy and meat products may still be consumed sparingly to obtain specific essential nutrients not included in a diet free of all animal foods. A plant-based diet emphasizes eating only whole, unprocessed foods as they occur in nature rather than processed, refined, or preserved food products. The difference between a plant-based diet and a vegan diet is that the vegan diet excludes animal products entirely.

Various healthy-eating trends and diets emerge from time to time as medical professionals and the public learn more about the role of nutrition in maintaining health and avoiding chronic disease. Diets in the twenty-first century include the Paleo diet, keto diet, clean eating, gluten-free eating, slow carb diets, macrobiotic diets, whole foods diets, and fruitarian, vegetarian, and vegan diets, among others. Plant-based eating has emerged as a flexible, plant-focused dietary plan that ensures consuming the essential nutrients needed by the body from mainly plant sources while eliminating foods found to be associated with health problems and chronic disease.

The concept of a plant-based diet is not new; it has a long history arising from vegetarian roots. During the Vedic period in India from 1500 to 500 BCE, a majority of the population followed a vegetarian diet for religious reasons, based on their idea that all living beings were of one family. In the 15th and 16th centuries, evidence from the famed Renaissance artist Leonardo da Vinci suggests that he and his contemporaries refrained from eating meat or poultry. In 1847, the Vegetarian Society was founded in Great Britain and still provides education and resources for individuals, families, and healthcare providers, as well as helping to legislate food-related policies in the United Kingdom.

In the United States, investigations of the meat-packing industries in the early twentieth century led to changes in the American meat-based dietary habits. The Food and Drug Administration (FDA) promoted Meatless Mondays in 1914, not as much for health reasons as to conserve meat for troops fighting in World War I; the program was promoted again in the 1940s during World War II, and even as late as 2003, collaborating with Johns Hopkins Bloomberg School of Public Health. Diet for a Small Planet was published in 1971, teaching readers about vegetarianism as a way to personal health, environmental health, and social stewardship; the book is still in print 50 years later. Although vegetarianism is still a popular way of eating in the United States, American food culture adopted a more flexible whole plant-food approach after “The Omnivore's Dilemma” was published by journalist Michael Pollan. The author investigated and reported on the troubled state of the U.S. meat- and dairy-based food system, the corresponding increase in chronic diseases such as diabetes and heart disease, and the difficulties associated with people making food choices. After much independent research on the food industry, and considering the results of major studies on dietary patterns and disease, Pollan summed up the solution to the food dilemma by stating simply that people should “Eat food. Mostly from plants.”

Although no single person developed the whole plant-based foods approach to eating for health, researchers and scientists from the United States, United Kingdom, China, and Canada have influenced the movement through prominent studies. An epidemiological study of 10,000 rural families in China was conducted during 1983 and 1984 with the cooperation of researchers from Cornell and Oxford universities, and more than 8,000 significant correlations were found between lifestyle, diet, and chronic disease. The Cornell biochemist and nutritionist, Dr. T. Colin Campbell, who released a notable book on that study (The China Study), describes how rural Chinese residents who reduced meat consumption also decreased the incidence of heart disease, diabetes, and cancers of the colon, lung, breast, stomach, and liver. Interestingly, no cut-off point was noted at which disease rates stopped decreasing in association with consuming animal products; no matter how much meat was consumed, risk of associated chronic disease persisted. Dr. Campbell has since founded the Center for Nutrition Studies at Cornell University and advocates for whole plant-based eating.

The Plant-Based Foods Association was founded in 2016, aiming to promote plant-based whole, unrefined food intake as a way to improve health and avoid chronic disease. The organization's mission is to promote the plant-based foods industry by removing obstacles to a fair and competitive marketplace for alternatives to animal ingredients and products. Their work has resulted in growth for the whole foods and plant-based foods industries, and increased awareness among health professionals and the public of the health benefits of plant-based eating.

Plant-based eating is focused on consuming whole, unrefined or unprocessed foods derived from plants, including fruits, vegetables, tubers (fleshy underground plants such as potatoes), whole grains, beans, and legumes. Refined sugars, flours, and grains are eliminated. Meat and dairy are not completely excluded from all plant-based diets but, if included at all, they are consumed in small portions and only occasionally. Some individuals consuming mainly plant proteins and whole foods from plant sources may also add certain dairy or meat products on occasion. They also focus on consuming whole foods rather than refined or processed foods, avoiding refined sugars, flours, and hydrogenated oils. Depending on the particular plant-based diet followed, some individuals may choose to exclude animal foods entirely, whereas others may include eggs and yogurt, for example, which is similar to lacto-ovo vegetarian diets, or red meats may be eliminated completely while fish and fowl are still consumed occasionally. For example, the Harvard Healthy Eating Plate presents a plant-based meal consisting of three-quarters vegetables, fruits, and whole grains with a quarter of plant proteins such as beans and nuts or small portions of fish or poultry. Cheeses, red meats, and processed meats (bacon, hotdogs, cold cuts) are excluded. The occasional addition of animal products helps to ensure that all of the essential micronutrients the body needs are provided. Whole plant-based foods contain all the essential nutrients except vitamin B₁₂, vitamin D₃, and heme iron. Calcium is provided by eating dark leafy greens regularly, although dairy products can be added as a source of calcium. Grains and vegetables provide sufficient plant protein. Good sources of plant proteins are easy to find. Some plant sources with higher percentages of protein include:

If the prospect of eliminating meat and dairy is overwhelming, Dr. Craig McDougall of Forks Over Knives, a website (and video) promoting plant-based eating, advises beginners to start a whole-food-based diet slowly, first adding about 1000 calories of whole grains, legumes (peas, lentils, seeds and pods of leguminous plants), and starchy vegetables (potatoes, sweet potatoes, root vegetables, beans) to the daily diet. The foods are filling and satisfying and will help make the switch from animal foods and processed foods easier. More importantly, these whole foods will not undermine an individual's health while transitioning to a whole plant-based diet.

Variations of a whole-food plant-based diet have been introduced and promoted by different individual health advocates such as dieticians and nutritionists and by various professional institutions and organizations, such as the diet introduced by T. Colin Campbell, PhD, at the Center for Nutrition at Cornell University in Ithica, New York. Dr. Camplbell urges individuals to consult with their physicians before changing their dietary plan because medications for existing medical conditions may need to be reviewed and adjusted if necessary.

The whole food plant-based diet of the Center for Nutrition is based on the following guidelines:

The whole plant-based diet allows dining out to remain satisfying and enjoyable. Many restaurants offer vegan or vegetarian options, and other restaurants offer healthy choices featuring plant foods. To find restaurants with the best choices for plant-based eating, check the options ahead of time as follows:

In addition to the health benefits, plant-based eating changes a percentage of land use from raising animals for food production to plant-based agriculture. Less water is used, better soil is produced and maintained, and air and water pollutants that may contaminate foods and the environment are significantly diminished. The environmental benefits of plant-based eating are described in the 2010 report of the United Nations on the Environmental Impact of Consumption and Production, which recommends that countries around the world make a shift away from meat and animal agriculture to ameliorate the effects of climate change. Anticipated population growth, if accompanied by increasing consumption of animal products, would increase the detrimental impact of agricultural methods on the environment. Dr. Edgar Hertwich, speaking for the UN study, said that “animal products cause more damage [to the environment] than construction minerals such as sand, cement, plastics or metals. Biomass and crops for animals are as damaging as [the burning of] fossil fuels.” Experts suggest that a worldwide change in dietary patterns away from animal products would substantially reduce factors causing climate change.

Plant-based eating is promoted by health professionals and adopted by individuals to support health and prevent chronic diseases such as diabetes, heart disease and other health problems, while also contributing to a healthier environment. Adopting a plant-based diet that includes more unrefined and unprocessed foods can be a motivator for other healthy behaviors such as cutting down on less healthy foods and exercising more, this in turn can increase feelings of wellbeing.

Plant-based eating helps to ensure that the essential micronutrients required by the body are provided in the diet through whole plant foods rather than risking deficiencies or relying on supplements. A diet of whole plant foods provides heart-healthy fats, vitamins, minerals, fibers, and protein. These nutrients are found in whole plant foods such as nuts, seeds, vegetables, fruits, grains, beans, and legumes. When oils are needed for cooking, only polyunsaturated vegetables oils such as olive and canola oils are used. Polyunsaturated fats are recommended by the Dietary Guidelines for Americans of the National Institutes for Health (NIH) for their beneficial effects on heart health. Certain essential nutrients such as vitamin B₁₂, vitamin D₃, and heme iron are only derived from animal products such as dairy, eggs, and meat. Vegetarians and vegans are often deficient in these nutrients, which can result in health problems. Dr. Ambika Satija from the Department of Nutrition at the Harvard T. H. Chan School of Public Health states that “for heart health protection, your diet needs to focus on the quality of plant foods, and it's possible to benefit by reducing your consumption of animal foods without completely eliminating them from your diet.” Individuals who eliminate animal products completely, nonheme iron can be obtained from certain foods (lentils, lima beans, soy beans and tofu, quinoa, brown rice, oatmeal, nuts, pumpkin and sunflower seeds, unhulled sesame seeds), vitamin D can be obtained through sun exposure (15 minutes per day in appropriate climates), and vitamin B₁₂ can be obtained only by taking supplements.

Plant-based eating must incorporate whole foods and exclude processed or refined foods to achieve its purpose. The types and quality of plant foods are especially important. White rice and white bread (made with refined wheat flour), for example, are plant-based foods. Most, however, are highly processed, have lost many heart-healthy nutrients, and have a high level of conversion to glucose (high glycemic index). Foods with a high glycemic index make blood sugar levels rise quickly, which may increase hunger and lead to overeating. Eating whole foods, even carbohydrates such as whole grains and whole fruit, slows absorption and avoids spiking sugar levels. The foods are absorbed slowly and completely, providing a steady supply of energy.

The American Heart Association (AHA) states that plant-based and vegetarian diets are lower in fat, sugar, and cholesterol than nonvegetarian diets, reducing the risks of obesity, heart disease, high blood pressure, diabetes, and some types of cancer. The AHA also notes risks linked to vegetarian, vegan, and plant-based eating associated with a lack of nutrients. A balanced plant-based diet must include protein, iron, zinc, calcium, vitamin B₁₂, vitamin D, and fatty acids. The diet must also avoid containing too many calories, unhealthy saturated fat, and reduced quantities of essential nutrients. A study conducted by the Harvard T. H. Chan School of Public Health also concluded that not all plant-based diets are healthy, especially those that allow processed and refined foods rather than emphasizing whole plant-based foods.

Plant-based diets that are not balanced may be deficient in specific nutrients that are particularly relevant during pregnancy, including fatty acids, vitamin B₁₂, iron, zinc, and iodine, possibly affecting the health of newborns. Maternal plant-based diets must be guided by the advice of an obstetrician, dietician, or nutritionist.

A study conducted over two decades by researchers from Harvard Medical School examined the dietary data of more than 200,000 adults and compared differences in heart disease risk after three separate groups consumed different plant-based diets. The diets were:

A Gallup poll in 2016 found that 5% of Americans consider themselves vegetarian or follow a plant-based diet. Dr. Anne Kulze, the author of the “Eat Right for Life” book series, cites the advantages of plant-based eating as having a lower risk of high cholesterol and high blood pressure, and less risk of developing heart disease or metabolic syndrome. A well-balanced vegetarian diet may be higher in complex carbohydrates and nutrients such as magnesium, folic acid, vitamin C, vitamin E, and phytonutreients, resulting in lower rates of heart disease, diabetes, and certain types of cancer. Individuals who wish to follow a plant-based diet are advised to consult with their physician or a dietician or nutritionist to evaluate their dietary choices and help to ensure that the dietary plan includes all essential nutrients and avoids potentially harmful deficiencies.

See also Sustainable diets .