Plant-forward diets are increasing in popularity across much of the Western world; data suggest that the number of US consumers eating entirely plant-based diets grew from nearly four million in 2014 to 19.6 million in 2017. A national Harris Poll in 2016 indicated that more than 3% of Americans are vegetarian, with more than half of that group identifying as vegan. Multiple motivations are driving this trend: improving animal welfare, lessening our environmental footprint, reducing disease risk and improving illness outcomes, etc. As a dietitian, I aim to help patients and the public who follow meatless diets (or diets devoid of all animal products) get nutrients through other foods or supplements and ensure their well-being.
How are vegetarianism and veganism defined?
Both vegetarian and vegan diets are considered “plant-forward.” Vegetarian diets consist primarily of plant-based foods and exclude animal flesh, but they may or may not include products originating from animals, such as eggs and milk. Vegan diets include no animal products whatsoever.
Cosmetics, processed foods, medications and various consumer goods may include ingredients derived from animals, making them inappropriate for a vegan diet. A few examples include:
Gelatin, which comes from cows’ or pigs’ connective tissue and is used as a thickener in various foods, vitamins and cosmetics
Animal rennet, which is extracted from calves’ stomachs and used in many types of cheese
Lactose, which comes from milk and is used in various medications
Carmine, which is derived from crushed insects and used to color various foods, cosmetics and personal care products
Packaging may not be labeled clearly or accurately, so consumers must use their discretion to avoid these products and/or choose plant-based alternatives. Individuals following plant-based diets may also classify foods and other consumer goods—those that contain ingredients or components such as honey or leather, for instance—differently depending on their compliance with a specific dietary pattern.
What are the benefits of following a plant-forward diet?
Overall dietary quality, as assessed by the Healthy Eating Index and Mediterranean Diet Score, is better among those following vegetarian diets. Following a vegetarian or vegan diet has been associated with myriad beneficial health outcomes, including:
Weight loss and/or maintenance
Lower blood pressure
Lower blood cholesterol
Lower body mass index (BMI)
Reduced risk of and improved outcomes from cardiovascular disease
Reduced risk of colon, prostate, breast and other cancers
Reduced risk of and enhanced outcomes from diabetes
Improved gut microbiome (which is associated with health benefits throughout the body)
What are the potential health risks of following a plant-forward diet?
The benefits described above have been proven through observational and experimental studies for many years. However, there are some risks of following a plant-forward diet if it isn’t planned and implemented thoughtfully—potentially leading to nutritional deficiencies, disordered eating patterns and/or even impaired relationships and social engagements.
People are often concerned about protein; indeed, vegetarians and vegans have fewer options for protein sources in their diets, and the protein in plant-based foods is less bioavailable. However, by consuming protein sources throughout the day and increasing portions slightly to compensate for lower digestibility, vegetarians and vegans can still meet their bodies’ needs for all essential amino acids (the building blocks that comprise protein molecules) and overall protein quantity. (Note that most healthy adults are recommended to have 0.8 grams of protein per kilogram of body weight per day: roughly 46 grams for the average woman and 56 grams for the average man.)
Several vitamins and minerals are found primarily or entirely in animal-based foods. Indeed, results from a 2021 systematic review in Clinical Nutrition showed that veganism is associated with deficiencies in several micronutrients but that low micro- and macronutrient intakes are not always associated with poor health. However, some of the studies reviewed suggested that vegans may have an increased risk of mental health issues, hematological disorders and other deficiency-related conditions. Considerations for these essential nutrients are shown in the table below.
Several groups of people may need additional guidance on dietary strategies and/or supplementation, and some may be advised against following a vegetarian/vegan diet (depending on their individual needs and medical histories). Examples of these groups may include:
Malnourished patients (especially those who are elderly) who struggle to consume enough nutrient-dense foods,
Patients with a history of an eating disorder or disordered eating patterns,
Young children (especially those who may be underweight),
Women who are pregnant or breastfeeding (and therefore have elevated nutrient needs),
Patients with diseases directly related to deficiencies of nutrients found primarily in animal-based foods (such as megaloblastic anemia or osteoporosis), and/or
Patients experiencing food insecurity or living in drought-prone areas with limited access to nutrient-dense vegetarian foods (and who might otherwise need to rely mainly on refined grains).
How can vegetarians and vegans ensure they meet their needs?
People following (or interested in following) one of these plant-forward diets should consider the following recommendations to ensure they meet their nutrient needs and are optimally healthy:
Continue to follow a balanced plate model to ensure all food groups are included in meals. Include vegetarian protein sources and healthy sources of fat—along with fruits, vegetables and whole grains—to be fully satiated and nourished.
Keep in mind nutrient pairings (such as iron and vitamin C) and food preparation methods (such as cooking in cast iron pans) that can help to maximize absorption and bioavailability to meet your body’s needs.
Plan ahead when eating out or sharing meals with omnivorous family and friends so that you ensure you will have options to eat; this might mean eating before attending an event, asking if a restaurant can make vegetarian substitutions and/or contributing a dish that you know you can eat and others will also enjoy.
If you wish to reduce your diet’s environmental footprint but don’t want to (or can’t) follow an entirely plant-based diet, consider reducing your portion sizes and/or the frequency with which you eat animal products; also aim to buy sustainably raised and locally grown meat, seafood and dairy products.
Talk with a dietitian about your individual nutrient needs and assess whether your diet (or intended diet) meets those needs and how to modify accordingly; also talk with a doctor and/or dietitian to consider whether supplements may be warranted.
For additional resources about vegetarian diets representing diverse cultures, tips for meeting nutrient needs, recipe ideas and meal plans, visit:
Resources
Bakaloudia DR, Hallorran A, Rippin HL, et al. Intake and adequacy of the vegan diet. A systematic review of the evidence.Clinical Nutrition. 2021; 40(5):3503-3521. sciencedirect.com/science/article/pii/S0261561420306567
Clarys P, Deriemaeker P, Huybrechts I, Hebbelinck M, Mullie P. Dietary pattern analysis: a comparison between matched vegetarian and omnivorous subjects.Nutrition Journal. 2013;12:82. d-nb.info/109871735X/34
Melina V, Craig Q, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets.JAND. 2016; 116(12): P1970-1980. jandonline.org/article/S2212-2672(16)31192-3/fulltext
Stahler C. How often do Americans eat vegetarian meals? And how many adults in the US are vegetarian? The Vegetarian Resource Group. 2016. vrg.org/nutshell/Polls/2016_adults_veg.htm
The Vegan Society Statistics. Accessed February 15, 2022. vegansociety.com/news/media/statistics
Christina Badaracco, MPH, RD
Christina is a registered dietitian and author who aims to improve access to healthy and sustainable food and educate Americans about the connections between food and health. She loves to experiment with healthy recipes in the kitchen and share her creations to inspire others to cook.
Christina completed her dietetic internship at Massachusetts General Hospital and earned her Master of Public Health degree from the University of California, Berkeley. Previously, she graduated with a degree in Ecology and Evolutionary Biology from Princeton University, after conducting her thesis on sustainable agriculture and energy in Kenya. She has done clinical nutrition research at the National Institutes of Health, menu planning and nutrition education at the Oakland Unified School District and communications at the Environmental Protection Agency's Office of Water. She has also enjoyed contributing to children’s gardens, farmers markets and a number of organic farms.