Pros and Cons of a Vegetarian Diet

sprouts on spoons

 Patrizia Savarese/Getty Images

Many people adopt a vegetarian diet in an effort to boost their health or reduce their risk for disease. Certainly, the benefits of a plant-based diet are well documented. But not all vegetarian diets are nutritious.

The type of foods you choose to include in your meal plan (and those that you choose to avoid) make a big difference in the benefits you gain. A vegetarian diet full of processed foods is less likely to provide health benefits than a diet full of nutritious fruits, vegetables, legumes and grains.

As you think about adopting this food plan, consider all of the pros and cons of a vegetarian diet to make sure it's the right eating plan for you.

Pros

  • Reduced risk of disease

  • May boost longevity

  • May increase food variety

  • Improved weight control

  • Complete nutrition

  • Reduced food costs

  • Environmental impact

  • Ethical treatment of animals

Cons

  • Possible nutrient deficiencies

  • Fewer food choices

  • Reduced satiety

  • Less convenient

  • Not always healthy

  • Exposure to chemicals

Pros

One of the advantages of a vegetarian diet is that there are different variations to choose from. The most common type is the lacto-ovo vegetarian—someone who avoids animal products and seafood but consumes dairy and eggs. Ovo-vegetarians eat eggs but avoid dairy, meat, and seafood. Lacto-vegetarians consume dairy but avoid eggs, meat, and seafood.

A vegetarian diet provides other benefits as well.

Reduced Risk of Disease

On a healthy vegetarian diet, you are encouraged to consume whole grains, legumes, fruits, vegetables, nuts, and seeds—foods that are lacking in the diets of many people who follow a more traditional food plan. These plant-based foods provide your body with important vitamins and minerals that boost your health and reduce your risk of many chronic diseases.

For example, in a large cohort study evaluating both vegetarian and vegan diets, researchers found that both groups experienced a reduced risk of cardiovascular diseases, cardiometabolic risk factors, and some cancers.

Other studies have confirmed those findings and have also found that plant-based eating may be helpful in the treatment and management of high blood pressure, diverticular disease, and eye cataracts.

There is also some evidence that a vegetarian diet may help you to avoid conditions such as gallstones and kidney stones.

A 2019 study published in the journal Nutrients followed over 4800 participants and concluded that by lowering cholesterol levels, a vegetarian diet successfully reduced the incidence of gallstone disease.

And a 2014 study investigating the effects of various diets on kidney stone formation determined that a balanced lacto-ovo-vegetarian diet can be protective against the condition as long as there is adequate calcium intake.

Longevity

There have been a number of studies investigating the link between vegetarian or vegan diets and longevity. Some studies have found that those who follow healthy plant-based diets live longer than those who eat meat.

A large cohort study published in 2014 found that vegetarians were 12% less likely to die from all causes combined compared to nonvegetarians.

However, results from studies like these can be tricky to interpret. The 2014 cohort study included 73,000 people but they were all Seventh-day Adventists who typically consume no alcohol and do not smoke. These factors may have played a role in their longevity patterns.

Other studies have investigated the link between plant-based diets and longevity, with many finding a positive association. But it can be hard to tell if it is the diet itself or related factors that boost longevity. For example, those who choose a vegetarian or vegan diet often practice mindful eating, exercise regularly and manage stress with meditation or yoga. These habits may also play a role in providing the benefit.

Wider Food Variety

The standard American diet is called an omnivore diet because no foods are excluded. But often, people who consume an omnivore diet get into the habit of eating the same foods day after day. The result is that they eat a relatively limited number of foods or types of food.

For example, a traditional American dinner generally includes meat (such as a steak or pork chop), a starchy side dish (such as a potato or rice), and maybe a vegetable. Dairy products are often used as ingredients, side dishes, or toppings.

On a vegetarian diet, however, many traditional foods are not compliant. Therefore, when you begin this diet, you may have to get creative and experiment with foods that are not familiar. For example, in the absence of meat, a hearty grain such as brown rice might become the foundation of your meal. Then to fill out your plate, you can rely on a variety of vegetables.

Of course, just choosing to go vegetarian does not guarantee this benefit. A vegetarian can also get into a food rut and eat the same (unhealthy) foods every day. But switching to a vegetarian diet may provide the motivation to experiment with new healthier food options.

Weight Control

Plant-based eating is often associated with losing weight. Studies have shown that those following a vegetarian diet typically consume fewer calories than an omnivore diet. Researchers have also found that the most restrictive variation—the vegan diet—is also likely to have the lowest caloric intake.

A broad evidence review published in 2017 found that plant-based diets are an effective tool in the management and prevention of overweight and obesity.

If you are trying to reach or maintain a healthy weight, the lower daily calorie intake associated with vegetarian or vegan eating may help you achieve your goal.

Complete Nutrition

Getting the recommended intake of both macro and micronutrients is easier on a vegetarian diet than it is on the more restrictive vegan diet. And while there are still some concerns about nutritional deficiencies on a vegetarian diet, there are substantial resources available to help you met your nutritional needs.

For example, the USDA and the U.S. Department of Health and Human Services included a Healthy Vegetarian Eating Pattern as part of their 2015–2020 Dietary Guidelines for Americans. The guide provides recommendations for the intake of various food groups such as green leafy vegetables, starchy vegetables, legumes and beans, soy products, and others. Recommended amounts are provided for daily caloric intakes ranging from 1000 to 3,200 calories per day.

By following this guide, you are likely to get the daily vitamins, minerals, and macronutrients needed for a healthy body. However, like any diet, you may fall short of nutrients if you don't take steps to eat a balanced diet.

Reduced Food Costs

Choosing a vegetarian diet may help you to reduce your food costs. But your total food costs will ultimately depend on the foods you choose to include in your meal plan.

Meat and seafood are typically expensive and for many are a major component of their total grocery bill. Convenience foods and fast foods that are not compliant on a vegetarian diet can also be pricey. When you remove these foods from your diet, you eliminate the substantial food costs that are associated with them.

Bulk grains and legumes are usually budget-friendly. And if you buy produce in season, you can cut costs as well. Off course, vegetarian-convenience foods and meat alternatives can be expensive, but they are likely to cost less overall than a diet rich in animal-based products.

Environmental Impact

There is increased concern in the environmental community about the impact of livestock and livestock farming practices on the earth. So, some people choose to eliminate meat and eat a vegetarian diet because they feel it is better for the planet.

The farming of plants to produce fruits, vegetables, nuts, seeds, and grains requires fewer land and water resources than the production of meat, poultry, and dairy. And cows produce more greenhouses gasses than plants, which leads some to believe that eliminating meat and dairy from the diet helps to reduce the risk of global warming.

Several research studies have even suggested that the vegan variation of a vegetarian diet is better for the planet than other diets, including the popular Mediterranean diet.

Ethical Treatment of Animals

Because no animals are killed to produce vegetarian foods, many choose this diet because of concerns about animal cruelty. However, those who choose to consume eggs and dairy may still have to confront issues regarding the treatment of chickens and cows.

Animal rights activists prefer that consumers choose a vegan diet to promote the ethical treatment of animals. But the less-restrictive vegetarian option still reduces the overall impact on the animal population.

Cons

Even though a vegetarian diet offers some substantial benefits, there may be drawbacks as well.

Nutritional Deficiencies

A well-rounded vegetarian diet can provide adequate nutrition. However, there are certain key nutrients that are generally found in animal foods that may be lacking in a vegetarian diet if the diet doesn't include a variety of healthy foods.

Nutrients that may be lacking in a vegetarian diet include vitamin B12, vitamin D, omega-3 fatty acids, calcium, and zinc.

Studies have shown even though zinc intake tends to be lower in vegetarians, their bodies tend to adapt to lower levels through increased absorption and retention of the mineral. Researchers also note that a well-planned diet can provide adequate zinc through plant-sources such as whole grains, tofu, tempeh, legumes, nuts and seeds, fortified breakfast cereals and dairy products.

Vitamin B-12, or cobalamin, is found in beef, liver, fish, shellfish, chicken and other meat-sources—foods not consumed on a vegetarian diet. But eggs contain vitamin B12, as well as some fortified breakfast cereals and dairy products. Researchers have found, however, that supplementation may be needed for people who follow a vegetarian or vegan diet.

Some researchers and health experts have raised concerns about vitamin D levels in vegans and vegetarians. The vitamin is found naturally in fish, fish liver oils, and egg yolks. But most of our vitamin D comes from exposure to sunlight. Two excellent vegetarian sources of vitamin D include maitake mushrooms and portobello mushrooms. Fortified nut milk and fortified grain products will help you get enough vitamin D during the winter months.

Vegetarians who do not consume dairy may need to plan meals carefully to get enough calcium. But green leafy vegetables, white beans, pulses, sesame seeds, and some dried fruits are rich in the nutrient.

Lastly, a vegetarian diet can be deficient in omega-3 fatty acids. But soy, pumpkin, flax, or chia seeds are good sources of omega-3, as well as kidney beans, walnuts, and edamame.

Fewer Food Choices

If you are used to consuming a traditional diet that includes meat, seafood, and other animal products, you may find the vegetarian diet to be limiting at first. Certainly, it takes time to adjust to the eating style if you are used to building meals around bacon at breakfast, deli meats at lunch, and beef or chicken at dinner. But there are a wide variety of resources to help you learn to find or create satisfying meals without meat.

Most vegetarians find that there are plenty of options not only in grocery stores and at restaurants, but even when dining with friends and family in private homes. Plant-based dishes are often encouraged by health experts for meat-eaters, so it is not uncommon to see hearty dishes that are vegetarian-friendly.

Less Filling

Studies have found that vegetarian diets tend to be lower in calories, fat, and protein than omnivore diets.  Foods that are higher in fat and protein help you to feel full and satisfied after eating. Some carbohydrate-rich foods such as fruit or refined grains are digested more quickly and may leave you feeling hungry soon after a meal or snack.

As a result, when you switch to a vegetarian diet, you may feel less satisfied and hungry more often.

But careful food choices can help boost satiety. Hearty beans and whole grains are high in fiber and help you to feel full. Snacks that include nuts or seeds also provide protein and fat to increase feelings of satisfaction after eating.

Less Convenient

Even though plant-based foods are getting easier to find, those who follow a strict vegetarian diet will still need to read ingredient lists, especially if they choose to consume processed foods. Foods that you might assume to be free from animal by-products may contain gelatin, whey, casein, or other foods that are non-compliant.

It is also important to read nutrition labels and choose foods that contain key vitamins and minerals to avoid nutritional deficiencies.

Dining out can also be a challenge, especially when you are first adapting to a strict vegetarian diet. While some restaurants provide meat-free meals, the meal may be made with dairy or other animal products. Vegetable soup, for example, might be made with chicken or beef broth, or even vegetable broth that used an animal bone for flavoring.

Eventually, you are likely to find restaurants with plenty of plant-based compliant meal choices. When dining at someone's home, bring a vegetarian recipe that you can enjoy and share with others.

Not Always Healthy

While consuming a vegetarian diet can provide health benefits and help you maintain a healthier weight, it is not a guarantee.

There is an increasing number of heavily processed vegetarian foods. Many times, these foods contain more fat, sodium, added sugar, and calories than their traditional counterparts.

Relying on these convenience foods leads to the same limited food palate and health concerns associated with the traditional American diet.

In fact, one study that investigated vegan diets found that those who followed a diet that included whole grains, fruits, vegetables, nuts, legumes, oils, tea, and coffee had a substantially lower risk for heart disease. But those who chose a less healthy version of the diet, including sweetened beverages, refined grains, potatoes, fries, and sweets had a higher risk. 

Exposure to Chemicals

There has been some concern in the health community about the increased risk of exposure to herbicides and pesticides among those who consume a plant-based diet.

In fact, some studies have shown that because fruit, vegetables, and grains are often farmed using these chemicals, vegetarians may be more exposed to pesticide residues than the general population due to specific dietary habits.

However, even though exposure to pesticides may be higher, other researchers have found that it is still likely to fall within safe guidelines. Additionally, it is not clear if the limited exposure has more potential for harm than exposure to hormones or antibiotics sometimes found in animal foods or if the potential exposure reduces the benefits gained by consuming a plant-based diet.

A simple solution to this concern is to buy organic foods. However, these products are often expensive and may not be available in all areas. If organic products are not an option for you, health experts advise that you wash fruits and vegetables carefully to limit exposure.

Was this page helpful?

Article Sources

  1. Le, L., & Sabaté, J. (2014). Beyond Meatless, the Health Effects of Vegan Diets: Findings from the Adventist Cohorts. Nutrients, 6(6), 2131–2147. doi:10.3390/nu6062131

  2. Nouvenne A, Ticinesi A, Morelli I, Guida L, Borghi L, Meschi T. Fad diets and their effect on urinary stone formationTransl Androl Urol. 2014;3(3):303–312. doi:10.3978/j.issn.2223-4683.2014.06.01


  3. Moore W, McGrievy M, Turner-McGrievy G.  Dietary adherence and acceptability of five different diets, including vegan and vegetarian diets, for weight loss: The New DIETs study. Eating Behaviors. 2015;19:33-38.

  4. Castañé, S., & Antón, A. (2017). Assessment of the nutritional quality and environmental impact of two food diets: A Mediterranean and a vegan diet. Journal of Cleaner Production, 167, 929–937. doi:10.1016/j.jclepro.2017.04.121

  5. Angela V Saunders, Winston J Craig and Surinder K Baines Zinc and vegetarian diets Med J Aust 2013; 199 (4): S17-S21. || doi:10.5694/mja11.11493


  6. Rizzo G, Laganà AS, Rapisarda AM, et al. Vitamin B12 among Vegetarians: Status, Assessment and SupplementationNutrients. 2016;8(12):767. Published 2016 Nov 29. doi:10.3390/nu8120767

  7. Clarys P, Deliens T, Huybrechts I, et al. Comparison of nutritional quality of the vegan, vegetarian, semi-vegetarian, pesco-vegetarian and omnivorous diet. Nutrients. 2014;6(3):1318–1332. Published 2014 Mar 24. doi:10.3390/nu6031318


  8. Satija A, Bhupathiraju S. et al.  Healthful and Unhealthful Plant-Based Diets and the Risk of Coronary Heart Disease in U.S. AdultsJournal of the American College of Cardiology. 2017;70(4):411-422. doi:10.1016/j.jacc.2017.05.047

  9. Van Audenhaege, M., Héraud, F., Menard, C., Bouyrie, J., Morois, S., Calamassi-Tran, G., Leblanc, J.-C. Impact of food consumption habits on the pesticide dietary intake: Comparison between a French vegetarian and the general population. Food Additives & Contaminants: Part A, (2009);26(10), 1372–1388. doi:10.1080/02652030903031171


Additional Reading