What Is a Vegetarian Diet?

vegetarian diet

Verywell / Debbie Burkhoff

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Are you considering a vegetarian diet for weight loss or wellness? Many people choose to give up meat for ethical reasons, because of environmental concerns, or to improve their health. But a vegetarian diet isn't the best choice for absolutely everyone.

A plant-based eating lifestyle can provide substantial health benefits, but like any diet, it is important to choose nutrient-rich foods and eat in moderation to get the benefits you're looking for.

What Experts Say

The vegetarian diet limits animal products to varying degrees. Experts agree this can be an earth-friendly and healthful way of eating, but care should be taken to ensure that food variety provides nutrition and satisfaction and is not a restrictive weight loss diet in disguise.

Chrissy Carroll, RD, MPH


Vegetarian diets have been around for thousands of years. According to some sources, Pythagoras, a Greek philosopher and mathematician, founded the first vegetarian society to promote non-violence among all species. He avoided meat for spiritual reasons, rather than health reasons. Ancient Buddhists and Hindus also practiced vegetarianism and many still do to this day. Until the mid-20th century, a diet that excluded meat was often called a Pythagorean diet.

The modern vegetarian movement began in the mid-1800s with the formation of the Vegetarian Society in England. The diet was associated with virtuous living and promoted temperance, abstinence, and self-control. Meat-eaters were depicted by the group as out-of-control, lustful, hooligans.

Vegetarian diets became popular in the United States in the early 1970s when "Diet for a Small Planet" was published by Francis Moore Lappé and became a bestseller. In the book, Lappé discusses the damaging impact of meat production on the environment and cites meat-based diets as a contributor to global food scarcity.

She suggests a vegetarian lifestyle as a more humanitarian approach and introduces the concept of food-combining to address concerns about inadequate protein intake.

In more recent times, both environmentalists and health experts continue to promote plant-based diets, such as the vegetarian diet, as healthier for our bodies and healthier for the planet. But as these diets have become commonplace, processed vegetarian foods have become more popular, making it easier to follow an unhealthy plant-based diet.

Currently, there are many different variations of the vegetarian diet. 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.

Some people consider the pescatarian diet to be a variation of a vegetarian diet. Pescatarians eat plant-based foods and seafood. The flexitarian diet is primarily a vegetarian diet but includes occasional meat or seafood-based meals. The vegan diet is the most restrictive vegetarian diet because it includes no meat, dairy, eggs, or animal by-products including honey.

How It Works

On the lacto-ovo vegetarian and lacto-vegetarian diet, you consume foods in all food groups including vegetables, fruit, grains, fat-free or low-fat dairy, protein foods, and oils. Those who adhere to a ovo-vegetarian diet would not consume foods from the dairy group. But milk alternatives (such as nut-based "milk" products) are widely available.

Instead of meat and seafood, vegetarians consume protein-rich grains, soy products like tofu and vegetables with protein. It is fairly easy to eat a balanced diet on a vegetarian plan and to get your recommended intake of nutrients.

The U.S. Department of Agriculture and the U.S. Department of Health and Human Services included a Healthy Vegetarian Eating Pattern as part of their 2020–2025 Dietary Guidelines for Americans. The guide provides recommendations for the consumption of various food groups based on intake goals ranging from 1,000 to 3,200 calories per day.

On a well-balanced vegetarian diet, you are also likely to limit some foods in accordance with the USDA's advice. For example, most of the saturated fat consumed in a standard American diet comes from meat and dairy products. Most of these foods are eliminated or reduced on a vegetarian diet.

You don't need to follow any specific meal timing when you begin a vegetarian diet. However, if you currently consume a traditional American diet, experts often recommend a gradual approach to make the transition easier.

Some people try going meatless one day each week before fully adopting the vegetarian diet. Others use the flexitarian diet and slowly eliminate meat from their diets.

Pros and Cons

You have the opportunity to gain substantial health benefits if you shift to a vegetarian diet. Several studies have shown that those who consume plant-based diets experience a reduced risk of cardiovascular diseases, cardiometabolic risk factors, and some cancers. There is also evidence that it may have preventative effects against high blood pressure, diverticular disease, eye cataracts, kidney stones, and gallstones.

A vegetarian diet may help you reach and maintain a healthy weight and some researchers even believe that a vegetarian diet can help you live longer.

There are also many people who follow a vegetarian diet to promote the ethical treatment of animals. While some animal products are consumed (if you consume eggs and dairy), this diet does not promote the farming of animals for slaughter. There is also evidence that a vegetarian diet is better for the environment.

The downside to this diet is that it is possible to have nutritional deficiencies if you don't follow a well-balanced eating plan. Nutrients that may be lacking in a vegetarian diet include vitamin B12, vitamin D, omega-3 fatty acids, calcium, iron, and zinc. In addition, without meat and seafood in the diet, it is possible (but not likely) that your protein intake may be lower than recommended.

Common Myths and Questions

Myth: A vegetarian diet always leads to weight loss

If you go vegetarian, you may lose weight. But weight loss isn't a slam dunk simply because you give up meat. Whether or not you slim down depends on how many calories you consume, not necessarily on the source of the calories.

However, if you shift to a vegetarian diet you may naturally consume fewer calories. Meat and dairy products are often high in fat and calories. Research has shown people following a typical vegetarian diet consume fewer calories daily than their meat-eating counterparts.

If you do want to lose weight on a vegetarian diet, focus on eating nutrient-rich complex carbohydrates. Complex carbohydrates are starchy, fiber-rich foods that are naturally low in fat and calories. Examples of complex carbs are legumes and other vegetables and whole grains.

Controlling portions sizes, choosing low-fat dairy, and cutting back on sugary sweets will help as well. Try to avoid foods that are heavily processed as these junk foods often provide too many empty calories and don't boost weight loss results.

Myth: A vegetarian diet is always healthier than other diets

A vegetarian diet can be healthier than an omnivore (unrestricted) diet. But it depends on the foods you choose to include in your eating plan.

Processed vegetarian foods, such as meat alternatives, cheese-like products, microwavable meals, and other convenience foods can be high in calories, high in fat, added sugar, and excess sodium. If your meal plan includes more of these foods, you are less likely to gain health benefits while on a vegetarian diet.

In fact, researchers have found that an unhealthy plant-based diet (including sweetened juices, refined grain products, potatoes/fries, sweets) is associated with a higher risk of coronary heart disease.

Researchers also have compared the vegetarian diet to other diets, including the vegan diet, pescatarian diet, and flexitarian diet using the Healthy Eating Index and other nutrient intake comparisons. They concluded that even though a balanced vegetarian diet fares well, the restrictive vegan diet is the most healthy.

How It Compares

Before you decide if a traditional vegetarian diet is right for you, see how it compares to similar eating plans to make sure you make the best choice for you


A vegan diet is similar to a vegetarian diet in that meat and seafood are not consumed. But vegans also do not eat eggs, dairy, or any food that contains any animal by-product including honey.

You are more likely to have nutritional deficiencies on a vegan diet, particularly a deficiency in vitamin B12. Vegans often take a supplement.

But if you are looking to gain health benefits or lose weight, this diet might be most effective. Researchers have found that even those who follow unhealthy vegan diets are likely to lose weight. And if you can stick to the plan, it can be a healthy plant-based eating plan. However, this diet is the most restrictive and can be hard to maintain for the long-term.


On a flexitarian diet, you eat primarily according to vegetarian guidelines. However, people who identify as flexitarian occasionally eat meat and seafood. On a flexitarian diet, you can easily meet the recommended nutritional guidelines provided by the USDA.

Because this diet is more flexible, it is the easiest plant-based program to maintain. And some health experts say that it is healthier because the occasional meat or seafood meal helps to boost protein intake and vitamin B12.


If you follow a pescatarian diet, you eat primarily plant-based foods but include fish and seafood in your diet as well.

Using the Healthy Eating Index, researchers scored the pescatarian diet about the same as the vegetarian and flexitarian diet. However, when using a different healthy eating scale based on the Mediterranean diet, this eating style scored higher than both the vegetarian diet and flexitarian diet.

While this plan is relatively flexible, fresh seafood and shellfish can be costly which means it may also be the most expensive.


A Mediterranean diet includes all food groups recommended by the USDA. Animal products are consumed, but minimally. The focus is on vegetables, grains, nuts, seeds, and plant-based healthy oils. The diet aligns with nutritional guidelines provided by the USDA and is associated with a wide range of health benefits.

The Mediterranean diet is also relatively sustainable. No foods are off-limits, but healthier choices are encouraged. The USDA also provides specific recommendations for those following a Mediterranean diet.

Getting Started

Starting a vegetarian diet can be challenging if you typically consume meals with meat and dairy. Most experts suggest that you start going meatless one day each week. Try new recipes, experiment with soy-based foods like tofu, whole grains, and new varieties of produce. Once you get comfortable with one meatless day, start to remove meat on other days until your diet is completely vegetarian.

You might also find it helpful to re-organize your kitchen and remove all foods that are not compliant on your new eating plan. For example, if you choose the ovo-vegetarian diet, you'll want to remove butter, milk, cream, yogurt, and foods that contain these ingredients. Try avocado or peanut butter instead of butter or cheese on toast and in sandwiches. Try different varieties of nut milk in cereal or coffee, and stock up on whole grains like oats, quinoa, or brown rice.

A Word From Verywell

If you're used to eating meat, shifting to a vegetarian lifestyle may take some time and effort. It might be easy to rely on meat alternatives and other foods that provide the same flavor and mouthfeel as meat. But if you branch out and learn to cook with whole, nutritious plant-based foods, you'll enjoy satisfying filling meals in the short-term and gain the long-term health benefits that this diet can provide.

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