Vegetarianism is a popular diet choice, whether temporary or lifelong. But what exactly does it mean to be a vegetarian? In the most basic sense, vegetarians do not eat meat. There are different classifications of vegetarianism, including lacto-ovo-vegetarians and even vegans, but all vegetarians do not eat meat, seafood, or poultry products of any kind.

What Is a Vegetarian Diet?

Vegetarian diets are commonly defined by what they exclude rather than what they include. All vegetarians exclude meat products, including beef, chicken, pork, and seafood. Beyond that, further food restrictions are up to the eater. For example, many people do not allow eggs on a vegetarian diet, whereas others prohibit certain types of cheese in a vegetarian diet due to the use of rennet, which can be animal-based.

When vegetarianism started to spread in the United States in the 1960s and 70s, the so-called house salad and pasta dishes were often the only options available to vegetarians on restaurant menus. But as awareness rose and adoption spread, the rich variety of a vegetarian diet gained commercial appeal. Restaurant kitchens from fast food to fine dining now serve tasty and inventive vegetarian meals that appeal to meat-eaters and non-meat eaters alike.

There are several different types of vegetarian diets:

Lacto-Ovo-Vegetarian: A diet that prohibits meat, poultry, and seafood products, this is the most common type of vegetarianism. Dairy and eggs are allowed. If you follow a lacto-vegetarian diet, then you also refrain from eating eggs in addition to meat products. Ovo-vegetarians consume eggs but not dairy.

A diet that prohibits meat, poultry, and seafood products, this is the most common type of vegetarianism. Dairy and eggs are allowed. If you follow a lacto-vegetarian diet, then you also refrain from eating eggs in addition to meat products. Ovo-vegetarians consume eggs but not dairy. Pescetarian: A pescetarian does not eat meat or poultry but does eat fish. They may also include dairy and eggs in their diet if they wish.

A pescetarian does not eat meat or poultry but does eat fish. They may also include dairy and eggs in their diet if they wish. Vegan: The most restrictive form of the vegetarian diet, vegans do not consume any animal products of any kind. This includes meat, seafood, dairy like cheese and milk, and eggs.

The most restrictive form of the vegetarian diet, vegans do not consume any animal products of any kind. This includes meat, seafood, dairy like cheese and milk, and eggs. Flexitarian: If you can't quite commit to cutting out all meat, a flexitarian diet allows for occasional meat or seafood. A flexitarian follows a lacto-ovo-vegetarian or even vegan lifestyle most of the time, only consuming meat or seafood every once and a while.

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Benefits of a Vegetarian Diet

There are a number of reasons for adopting a vegetarian diet. Some eat vegetarian for religious reasons, while others adopt the way of eating out of environmental and/or animal rights concerns. A vegetarian diet is also linked to several health benefits, such as a lower BMI (body mass index) rating, lower cholesterol, and lower risk of heart disease and type 2 diabetes﻿﻿ .

A vegetarian diet may also make it easier to address other dietary concerns, such as lactose intolerance and some food allergies. Additionally, plant-based diets can result in a lower grocery bill. Meat, poultry, and seafood are not typically cheap, while many vegetarian options like beans, grains, and veggies, are budget-friendly. Some shoppers find that by reducing their meat consumption they are able to save money at the store, too.

Potential Downsides of a Vegetarian Diet

While there are many benefits to a vegetarian diet, some eaters find the lack of meat and seafood too restrictive. If you're thinking of adopting a vegetarian diet but are concerned about making well-rounded meals without meat, consider starting with a flexitarian diet.

Because a vegetarian diet does not include meat, it is possible to develop some vitamin deficiencies if you're not eating well-balanced meals﻿﻿ . Meat, poultry, and seafood are good sources of protein, omega-3 fatty acids, iron, calcium, zinc, and vitamin B12. To avoid any nutritional deficiencies, eat a well-balanced diet that includes high-protein foods like beans and tofu, foods rich in calcium and iron like leafy greens, and, if needed, supplement with vitamins.

What to Eat

Anything that is not restricted by your chosen type of vegetarian diet is allowed. For most people, that will mean any non-meat, poultry, or seafood products. For a balanced diet, include a mix of beans, tofu, nuts, and similar protein-rich products along with whole grains and a wide range of vegetables and fruit. Eggs and dairy products also add protein and nutrients if you're choosing to include them in your diet.

A wide range of vegetarian "meat" products are also available, simulating beef, chicken, and other meat. These can include veggie burger patties, "chicken" nuggets, and more. These can be a good option for adding heft to meals, but be sure to pay attention to how much fat and sodium these products add to your diet. Other meat substitutes can include tempeh, made from fermented soy, and seitan, made from wheat gluten.

Some cuisines rely heavily on plant-based meals, such as Indian, Ethiopian, and Burmese. However, you'll find plenty of creative vegetarian recipes from a range of countries and cultures. Try a hearty, cheesy, vegetarian lasagna, a quick tofu stir-fry with ginger sauce, vegan cauliflower tacos, a fragrant Thai yellow curry, veggie burgers with your choice of toppings, or a perfectly spiced vegetarian Indian dish.

What Not to Eat

Food items that should be avoided on a vegetarian diet will depend upon the exact type of diet you choose to follow. For all vegetarian diets, all meat including beef and pork, poultry, and seafood are not allowed, as well as any products made using meat. This includes stock or broth made from meat or seafood (opt for vegetarian broth instead), gelatin products (unless marked as vegan), and meat fats like lard, tallow, or suet. Processed meat products like bacon, sausage, jerky, and lunchmeat are also prohibited.

Some vegetarians also exclude several types of cheese. Most cheesemakers use rennet during the cheese production process. Rennet traditionally comes from the stomach lining of a calf or baby goat, making the cheese not strictly vegetarian. A number of cheeses are now made with vegetarian or genetically engineered rennet, making the cheese vegetarian-friendly. If you're not sure about your favorite cheeses, do your research before buying.

Ovo-vegetarians do not consume any dairy products, including milk, butter, cream, yogurt, and cheese. Lacto-vegetarians enjoy dairy but do not consume eggs or any products that contain eggs, including conventional baked goods. When shopping with diet restrictions, it's always important to read food labels before you purchase. Don't be afraid to ask questions at restaurants, too.