Published 26th September 2022

A guide to the vegetarian diet

A vegetarian diet is any that leaves out meat, poultry, and seafood. There are several types, each with its own guidelines.

A vegan diet eliminates all foods that come from animals, including eggs and dairy.

Lacto-vegetarians, meanwhile, don’t eat eggs, poultry, meat, or seafood, but they do consume dairy.

Lacto-ovo vegetarians don’t eat meat, poultry, or seafood but do eat eggs and dairy products. This is what many traditionally think of as a vegetarian diet.

Pescatarians and flexitarian diets aren't technically vegetarian, but they tend to involve eating less meat.

A pescatarian avoids most meat but eats fish, while a flexitarian eats small amounts of meat. 

Consuming less meat can have some powerful health benefits, such as lowering the risks of cancer and heart disease. Research also shows that vegetarians and vegans have lower blood cholesterol and fasting glucose levels. 

And there are several benefits for the environment, as well.

Overfishing and the mass production of meat both damage the planet. In fact, one study found that global greenhouse gas emissions from processing and transporting animal-based food products were twice those of plant-based foods.

So even just cutting down the amount of meat in your diet may help protect your health and that of our planet.

Your body and gut microbiome are unique, so finding the best diet can be a puzzle. With the ZOE at-home test, we’ll tell you about your blood sugar and blood fat responses, as well as the bugs living in your gut. With this information, we’ll provide nutrition advice tailored to you.

Take our free quiz to get started.

A healthy vegetarian diet

It may be obvious, but just switching to any vegetarian diet won’t automatically improve your health. A vegetarian diet might involve eating only french fries, and this isn’t good for anyone.

One tip is to focus on eating whole foods rather than ultra-processed versions. Whole foods have been minimally (or not at all) processed.

While processing isn't necessarily bad, foods that have been through lots of industrial processes tend to have fewer nutrients and higher levels of unhealthy fats, refined sugars, and salt.

And, of course, balance is crucial — the aim is to include a variety of food groups. Eating many different plants also has the benefit of supporting a healthy gut. In a nutshell, the more plants, the better.

Some key food groups in a healthy vegetarian diet include:

  • vegetables, such as broccoli, carrots, leafy greens, cabbage, and asparagus

  • fruits, such as apples, pears, oranges, bananas, berries, and tomatoes

  • legumes, such as beans, chickpeas, and lentils

  • whole grains, such as quinoa, brown rice, bulgar wheat, and buckwheat

  • nuts and seeds, such as flax, hemp, sunflower, peanuts, almonds, and pistachios

  • non-meat proteins, such as tofu, tempeh, and soybeans

  • herbs and spices, such as turmeric, ginger, and coriander

  • dairy products, such as yogurt, cheese, and milk

  • eggs

Some foods to eat less frequently include:

  • foods with refined sugars, such as donuts, cookies, cake, and ice cream

  • fried foods and fast food

  • processed plant-based alternatives, such as some vegan cheeses, burgers, and sausages

It’s important to note that plant-based alternatives aren't necessarily healthy. 

Many of the increasingly common vegan or vegetarian versions of classic favorites, like hamburgers and hotdogs, are highly processed and have high levels of salt, as well as several additives.

A recent episode of the ZOE Science & Nutrition podcast explored the contents of meat alternatives. Overall, while these can be tasty, it’s best not to eat them frequently. Instead, try out a homemade bean or lentil burger.

Nutrient deficiencies

While certain nutrients may be harder to find in plant foods, there are some misconceptions about nutrient deficiencies in vegetarian diets.

The richest sources of long-chain omega-3 fatty acids tend to be oily fish and seafood. However, algae and seaweeds also contain high quantities

Several nuts and seeds, such as walnuts, pumpkin seeds, and flax seeds, also contain essential omega-3s that your body can convert into long-chain omega-3s. 

People often associate vegetarian diets with an iron deficiency. While red meat is a rich source of iron, plenty of plant foods also contain high amounts. Some examples are beans, lentils, spinach, and kale.

It’s true that the body absorbs iron from plant sources less efficiently than iron from animal sources. But you can increase the availability of iron in plants by eating sources of vitamin C, such as fruits and vegetables.  

Vitamin B12 famously only exists in animal products, but vegetarians can get plenty of it from dairy, eggs, and supplements.

If you’re vegan, the only reliable sources of this vitamin are fortified foods and supplements. And you might also consider fortified foods or supplements that contain iodine and calcium.

Food swaps and meal ideas

There are plenty of easy ways to swap out meat. 

Some simple replacements might involve:

  • using lentils or beans instead of ground beef in pasta sauces and chilis

  • opting for sweet potatoes or tofu instead of chicken

  • trying a portobello mushroom cap or some eggplant instead of a burger patty

  • replacing the ground meat in tacos with cauliflower

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The following recipes may be a good place to start.

Breakfast

Scrambled tofu, spinach, and tomato burrito

Scrambled tofu with turmeric and other spices can be a healthy, protein-packed burrito filling. You might add eggs and your favorite veggies into the mix for more nutrients and protein.

Oatmeal with berries and nuts

Dropping a handful of berries and nuts into oatmeal can make a convenient, satisfying breakfast. Try adding some Greek yogurt for extra protein.

Pancakes with berries

Pancakes can be a delicious, warm, and filling vegetarian breakfast. Top them with some berries for the added fiber and vitamins.

Hash browns with beans and fried mushrooms

For a more savory option, try hash browns with baked beans, mushrooms, and any other fried veggies on the side.

Lunch

Greek pasta salad

In a big bowl, combine cooked orzo pasta, lemon juice, and some diced cucumber, tomato, onion, feta cheese, olives, parsley, and marinated artichoke hearts. Then, for the best results, leave it to chill for 1 hour.

Falafel wrap

This is a vegetarian staple. Arrange some falafel and your favorite chopped vegetables in a tortilla for a filling, healthy lunch. If you’re up for more of a challenge, try making your own falafel.

Black bean and sweet potato tacos

Trade the ground meat for black beans and sweet potatoes, then add the classic taco fillings like sour cream, tomatoes, and lettuce for a nutritious alternative. 

Vegetarian fajitas

One easy option is to grab your favorite fajita recipe and go for sliced veggies instead of chicken, beef, or pork.

Dinner

Lentil lasagna

Pasta can be a great vegetarian option. When making lasagna, fry some cooked lentils, onion, and garlic together and use this instead of meat. The rest of the process is the same.

High in iron and low in saturated fats, lentil lasagne can be a healthy alternative packed with flavor.

Stir fry with veggies, tofu, and peanut sauce

Simply swapping out meat for some crumbled or cubed tofu can be an easy way to keep enjoying your favorite stir-fry dishes. The veggies and noodles can stay the same. But if you don't eat seafood, have a look at your sauce's ingredients.

Spinach, sweet potato, and lentil dahl

Dahl is a wonderful Indian dish. Spices, vegetables, and lentils combine to make an iron- and protein-rich vegetarian curry. 

Health benefits

Research into the health benefits of vegetarianism and plant-based eating has become more common as more people are following these diets.

Some of the key health benefits may involve your:

Gut microbiome

Vegetarian and vegan diets appear to promote a healthy gut microbiome, in part due to the abundance of fiber and polyphenols

A healthy vegetarian diet involves a diverse selection of plant foods. The American Gut Project found that people who eat 30 different types of plants each week have a more diverse gut microbiome, full of beneficial bacteria, than those who eat 10 or fewer plants per week.

Cardiovascular health

Cardiovascular diseases are the leading cause of death worldwide, being responsible for 43.6% of deaths. 

A review from 2019 found a 28% reduction in the incidence of coronary heart disease among people with a vegetarian diet. 

The same team also found a 22% lower mortality rate from cardiovascular conditions among people with this type of diet. 

Diabetes risk

The prevalence of diabetes is 1.6 to 2 times lower in vegetarians than in non-vegetarians. 

This is likely due to factors associated with a vegetarian diet, such as better weight control, lower intake of saturated fats, and higher fiber intake. Each of these plays a role in improving insulin resistance and diabetes risk.

Cancer prevention

A vegetarian diet may reduce the risk of certain cancers. In fact, one meta-analysis with over 124,000 participants found that vegetarians had a significantly lower rate of cancer, compared with non-vegetarians.

Other research suggests that this may be related to the higher fiber intake and better weight control associated with vegetarian diets.

Risks of a vegetarian diet

Like all things, a vegetarian diet can involve some risks.

First, this type of diet in itself is not automatically healthy. Pay close attention to what goes into your meals and snacks, try to reduce your intake of ultra-processed foods, and aim to eat whole foods more often.

That being said, recent research refutes claims that having a fully balanced diet is harder for vegetarians than for meat eaters.

Summary

Research suggests that vegetarian diets provide many health and environmental benefits.

Just eating less meat can have a tremendous effect — it can reduce the risk of certain diseases, as well as greenhouse gas emissions.

While researchers associate vegetarianism with plenty of benefits, the key is to focus on a diet that is healthy overall.

This means it should include a diverse, balanced range of plants, legumes, eggs, dairy, whole grains, nuts, and seeds. If you decide to exclude animal products completely, it’s important to pay attention to particular nutrients, such as vitamin B12 and iodine.

Becoming vegetarian may seem challenging, but the variety of recipes and options in restaurants is always growing, which can make the transition easier.

Different diets work better for different people. There is no one-size-fits-all approach to nutrition. With the ZOE at-home test, we can tell you how your body responds to different foods. 

By analyzing your blood sugar and blood fat responses, as well as your gut microbiome, we provide personalized nutrition advice to help you eat the best way for your body.

To get started, take our free quiz.

Sources

American gut: An open platform for citizen science microbiome research. mSystems. (2018). https://journals.asm.org/doi/epub/10.1128/mSystems.00031-18

Bioavailability and potential uses of vegetarian sources of omega-3 fatty acids: A review of the literature. Critical Reviews in Food Science and Nutrition. (2014). https://pubmed.ncbi.nlm.nih.gov/24261532/

Cardiovascular disease mortality and cancer incidence in vegetarians: A meta-analysis and systematic review. Annals of Nutrition and Metabolism. (2012). https://www.karger.com/Article/FullText/337301

Dietary patterns and cardiometabolic outcomes in diabetes: A summary of systematic reviews and meta-analyses. Nutrients. (2019). https://pubmed.ncbi.nlm.nih.gov/31540227/

Easy baked falafel with cucumber-yogurt sauce. (n.d.). https://www.allrecipes.com/recipe/270463/easy-baked-falafel-with-cucumber-yogurt-sauce/ 

Global greenhouse gas emissions from animal-based foods are twice those of plant-based foods. Nature Food. (2021). https://www.nature.com/articles/s43016-021-00358-x

Greek orzo salad. (n.d.). https://www.allrecipes.com/recipe/19389/greek-orzo-salad/ 

Iron and vegetarian diets. Medical Journal of Australia. (2013). https://pubmed.ncbi.nlm.nih.gov/25369923/

Nutritional update for physicians: Plant-based diets. The Permanente Journal. (2013). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3662288/

Omega-3 polyunsaturated fatty acids: Benefits and endpoints in sport. Nutrients. (2019). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6357022/

Spicy Indian dahl. (n.d.). https://www.allrecipes.com/recipe/13059/spicy-indian-dahl/ 

The effects of vegetarian and vegan diets on gut microbiota. Frontiers in Nutrition. (2019). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6478664/

The environmental cost of animal source foods. Frontiers in Ecology and Environment. (2018). https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/fee.1822

Tofu and veggies in peanut sauce. (n.d.). https://www.allrecipes.com/recipe/25312/tofu-and-veggies-in-peanut-sauce/ 

Vegan cilantro-lime, sweet potato, and black bean tacos. (n.d.). https://www.allrecipes.com/recipe/264310/vegan-cilantro-lime-sweet-potato-and-black-bean-tacos/ 

Vegan diet, subnormal vitamin B-12 status and cardiovascular health. Nutrients. (2014). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4145307/

Vegetarian diet: An overview through the perspective of quality of life domains. International Journal of Environmental Research and Public Health. (2021). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069426/

Vegetarian fajitas. (n.d.). https://www.bbcgoodfood.com/recipes/veggie-fajitas 

Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Critical reviews in food science and nutrition. (2017). https://pubmed.ncbi.nlm.nih.gov/26853923/

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