Vegetarian diets have grown in popularity, especially over the last several years.

People often consider this way of eating — emphasizing plant foods over animal products — as part of the plant-based movement.

There are many reasons more people are choosing a vegetarian diet, and several variations of how to approach this way of eating.

This article reviews 6 variations of the vegetarian diet, including which foods to include and avoid in each. It also explores a few common reasons why people choose a vegetarian diet.

Person preparing a vegetarian mealShare on Pinterest
Photography by Aya Brackett

There are three main reasons why someone might choose to follow some variation of a vegetarian or plant-based diet. These are related to personal and public health, the environment, and the animals raised for food.

Studies have found that animal products, especially those produced in large-scale concentrated animal feeding operations (CAFOs), are likely to contain unwanted substances, such as antibiotics (1).

Research suggests that antibiotic use in animal feed may lead to the development of antibiotic-resistant bacteria in humans (1).

Research has also shown individual health benefits of well-planned, nutritionally adequate vegetarian diets.

They can support weight loss and may help lower your risk of obesity and chronic diseases like type 2 diabetes, heart disease, and cancer (2, 3, 4, 5).

Environmentally speaking, many people choose to not support industrialized animal agriculture due to its negative impacts on soil, water, and air (1, 6, 7).

For example, manure and nutrient runoff from CAFOs can contaminate groundwater. This may make its way to the ocean and contribute to the development of dead zones, areas in the ocean where most life has disappeared due to lack of oxygen (8).

Furthermore, CAFOs and the animals kept there generate greenhouse gases, including methane, nitrous oxide, and carbon dioxide. These contribute to global climate change (9, 10).

Some people choose a vegetarian diet as a way to support animal welfare and align with their personal ethics. CAFOs house large populations of animals, often packed tightly together in unhealthy conditions and slaughtered for food after a short lifespan (11, 12).

People also have ethical concerns with the dairy industry, including taking milk from cows that have just given birth and separating them from their calves shortly after birth (13).

Some people may find that a vegetarian diet is more cost-effective for their household, or they may simply prefer the taste of plant foods over certain animal-derived products.

The many variations of a vegetarian diet allow you to choose a way to eat that best aligns with your ethics and goals.

Summary

Most people choose to adopt some form of a vegetarian or plant-based diet due to health, environmental, or ethical reasons. Different diet variations may better align with your personal goals and ethics.

Some people think of a lacto-ovo-vegetarian diet as the most traditional vegetarian diet. In this variation, you wouldn’t eat meat or fish, but would still include eggs and dairy products in your diet.

The prefix “lacto” refers to cow’s milk or dairy products and comes from the Latin word lac, which means milk. Only mammals, like cows and humans, can produce milk.

The prefix “ovo” refers to eggs and comes from the Latin word ovum, which means egg.

Following a lacto-ovo-vegetarian diet means including eggs, milk, cheese, butter, yogurt, sour cream, ice cream, and other dairy products in your diet, while excluding all animal-derived meats, such as beef, fish, chicken, and pork.

Some people have religious or cultural reasons for choosing this variation. For instance, people who follow Hinduism and Buddhism may follow a lacto-ovo-vegetarian diet (14, 15).

Summary

A lacto-ovo-vegetarian diet includes eggs and dairy products, but typically excludes all meats, including fish, chicken, pork, and beef.

A lacto-vegetarian diet is a plant-based diet that includes dairy products, as the “lacto” prefix suggests.

This variation includes dairy products like cow’s milk and foods made with it. These can include cheese, butter, sour cream, yogurt, and ice cream.

It excludes all meats, like beef, pork, chicken, and fish. It also excludes eggs.

As with the lacto-ovo-vegetarian diet, people may have religious or cultural reasons for following a lacto-vegetarian diet. This variation is common among people who follow Jainism, Hinduism, and Buddhism (14, 15).

Summary

A lacto-vegetarian diet includes dairy products, such as milk, cheese, yogurt, and ice cream, but excludes eggs, meat, and fish.

An ovo-vegetarian diet doesn’t include dairy products, but does incorporate eggs, as the “ovo” prefix indicates.

In addition to excluding meat and fish, an ovo-vegetarian diet excludes all dairy products and foods made using them, such as cow’s milk, cheese, butter, sour cream, yogurt, and ice cream.

However, someone on an ovo-vegetarian diet would include eggs and egg dishes, like scrambled eggs, hard-boiled eggs, and omelets. They may also use eggs in baking, such as in muffins, cakes, and breads.

Summary

An ovo-vegetarian diet is a variation that includes eggs in all forms, but doesn’t include dairy products, meat, or fish.

A flexitarian diet is designed to be more flexible than a strict vegan or vegetarian diet, as indicated by its “flexi” prefix. It emphasizes the benefits of plant-based foods while allowing small amounts of animal products.

It takes a primarily plant-focused approach to eating, but includes some meat and other animal products, like eggs and dairy, in moderation.

The main principles of a flexitarian diet include eating mostly whole plant foods, getting most protein from plants instead of animals, limiting added sugar and processed foods if possible, and incorporating meat and animal products occasionally (16).

A flexitarian wouldn’t technically be considered a vegetarian because they eat small amounts of meat sometimes. It’s up to the individual to design the diet to fit their lifestyle.

Summary

A flexitarian diet is designed to emphasize plant foods while also being flexible by occasionally incorporating meat and animal products in small amounts.

A pescatarian diet is a plant-based diet that includes fish. The prefix is derived from the Italian word “pesce,” meaning fish.

While someone on a pescatarian diet will consume fish-based foods, like tuna, halibut, salmon, or sushi, they’ll typically avoid other meats, like beef, chicken, or pork.

Whether a pescatarian diet includes dairy products and eggs tends to vary from person to person.

A pescatarian diet offers the benefit of getting healthy omega-3 fatty acids from fish and seafood. These may otherwise be lacking in certain vegetarian diets (17).

Summary

A pescatarian diet includes fish but doesn’t include other meats, like beef, pork, or chicken. A pescatarian diet may include dairy products and eggs, but this depends on personal preference.

A vegan diet is one that excludes all animal-derived products, including all meats and fish, dairy products, and eggs. Some people on a vegan diet also choose to exclude honey because it’s produced by bees.

Ethics are a major reason why some people choose a vegan diet.

A vegan diet is based solely on plant foods. This includes fruits, vegetables, grains, nuts, seeds, and legumes, including beans, peas, and lentils.

A vegan diet may incorporate plant-based alternatives to traditional animal products, such as plant-based milk and dairy products, plant-based egg substitutes, and plant-based meat replacements like tofu, tempeh, seitan, and jackfruit.

Another distinction of the vegan diet is that it tends to extend beyond food choices and into a person’s everyday life.

For example, someone on a vegan diet may avoid purchasing consumer products — such as cosmetics, clothing, and shoes — that use animal-derived ingredients or have been tested on animals.

Vegan diets tend to be low in some nutrients. For this reason, healthcare providers often recommend vegans take certain vitamin and mineral supplements, including vitamin B12, iron, omega-3 fats, zinc, and more.

Summary

A vegan diet is entirely based on plant foods, excluding all animal-derived ingredients. Veganism typically extends beyond the plate, excluding consumer products that use animal ingredients or are tested on animals.

When choosing which variation of a vegetarian diet is right for you, it’s important to consider factors like sustainability, cost, and nutritional quality.

Furthermore, considering which variation best aligns with your personal values and goals is an important factor when determining how sustainable it will be for you.

If a way of eating isn’t realistic for your lifestyle and doesn’t align with what’s important to you, it will be much harder to sustain.

What’s nice about all the types of vegetarian diets is that you can experiment with different variations and adjust accordingly until you find a good fit for you.

Summary

There are many approaches to a vegetarian diet. The best one for you depends on your personal goals and ethics, as well as how sustainable the diet is for your lifestyle.

A vegetarian diet is a primarily plant-based diet that may or may not allow certain animal-derived products, depending on the variation.

Plant-based diets can improve health, help protect the environment, and support animal welfare.

Variations of a vegetarian diet exclude meat but may include eggs, fish, dairy products, or a combination of these.

A flexitarian diet focuses on plant foods, but does include small amounts of animal products, including meat.

A vegan diet doesn’t incorporate animal products at all, and this extends beyond food into everyday lifestyle and consumer choices.

Choosing a vegetarian diet can offer numerous health and ethical benefits. The best diet for you depends on factors like nutritional quality, cost, ease of use, and how easy it will be for you to sustain.