The Vegetarian Diet

by Irene Mejia | Nov 14, 2023

The vegetarian diet has gained considerable popularity in recent years as people become more conscious of their health, environmental impact, and animal welfare concerns.

This dietary choice involves abstaining from meat, poultry, and fish, and often includes a wide array of plant-based foods.

While vegetarianism has deep historical roots and offers several potential benefits, it is essential to understand its basics, pros, and cons before making the decision of starting a vegetarian diet.

This article aims to provide an in-depth look at the vegetarian diet, differentiating it from related dietary choices, and exploring its advantages and disadvantages.

The Vegetarian Diet Basics

The Origins and Definition

The vegetarian diet has ancient origins, dating back to various cultures and philosophical traditions around the world.

One of the earliest recorded instances of vegetarianism can be traced to India (1), where it has been practiced for thousands of years. Meanwhile, in the West, the concept of vegetarianism gained prominence in the 19th century.

A vegetarian diet is defined by the exclusion of meat, including poultry and seafood, from one’s meals. However, it allows for the consumption of plant-based foods, such as vegetables, fruits, grains, legumes, nuts, seeds, and dairy products.

Difference with Plant-Based and Vegan Diets

To better understand the vegetarian diet, it is essential to differentiate it from plant-based and vegan diets, which often share similarities.

Plant-Based Diet

In a plant-based diet you can still eat animal products (meat, fish, eggs…), but most of your nutrients come from whole, plant-based products. (2)

A common recommendation is to fill ⅔ of your plate with plant-based products (fruits, vegetables, grains, legumes, nuts, seeds…).

Vegan Diet

Veganism is a more extreme vegetarian diet that eliminates all animal products and byproducts, including meat, dairy, eggs, and even products like honey and gelatin.

While some people choose to become vegan to have a healthier lifestyle, most people are motivated by ethical concerns related to animal exploitation.

The ethical motivation behind veganism often extends beyond diet to encompass lifestyle choices that avoid using animal-derived materials in clothing, cosmetics, and more.

Now that we differentiated the vegetarian diet from other similar ones, let’s discuss the pros and cons of the vegetarian diet.

Pros of the Vegetarian Diet

The vegetarian diet offers several potential advantages, making it an attractive choice for many individuals:

Health Benefits

a) Reduced Risk of Chronic Diseases: Numerous studies suggest that a vegetarian diet may reduce the risk of chronic diseases (heart disease, hypertension, type 2 diabetes), This is often attributed to the lower intake of calories, saturated fats and cholesterol (3).

b) Weight Management: Vegetarians tend to have lower body mass indexes (BMIs) on average and are less likely to be overweight or obese. This may be due to the higher consumption of fiber-rich foods and lower calorie density in plant-based meals (3).

c) Improved Digestive Health: A vegetarian diet rich in fiber from fruits, vegetables, and whole grains can promote healthy digestion.

d) Better Blood Sugar Control: Vegetarian diets can help improve insulin sensitivity, making them beneficial for individuals with or at risk of type 2 diabetes (the high-fiber low grains are digested slowly) (3).

Environmental Benefits

The production of plant-based foods generally has a lower environmental impact.

This information comes from the most extensive meta-analysis conducted so far on the environmental impact of global food production (4). The study found that 26% of the global greenhouse emissions were from food production.

Out of this 26%, 53% of greenhouse emissions were related to animals (livestock, fish farms, crops for animal feed, and land use for livestock), as opposed to 29% coming from crops for human consumption (5).

Feeding billions of people is impossible without causing emissions. Even rice emits methane, or we cut down forests to make room for crops. However, research suggests that the production of animal foods currently has the largest impact.

Ethical Considerations

One of the main reasons why people choose a vegetarian diet is animal welfare.

It may seem counterintuitive, since a vegetarian diet still includes animal byproducts, and also the production of crops can sometimes have detrimental side-effects in the environment (pesticides killing insects, fertilizers affecting water quality, etc.)

However, for many, there can be an inner fight between our morals, nutrient needs, and our social and financial limitations.

For example, some may desire to completely stop eating animal products because they truly feel bad about the living and killing conditions of farm animals. However, they may also have nutritional needs that prevent them from completely transitioning to a vegan diet.

Some may need higher protein needs, or some may not be able to afford a completely balanced, healthy vegan diet, so a vegetarian diet can be the second best alternative.

Our diets are a very personal topic, and as mentioned before, all types of diets will have an environmental impact, so it is up to us to pick and choose our battles.

Cons of the Vegetarian Diet

While the vegetarian diet offers numerous benefits, it also comes with its share of potential drawbacks:

Nutritional Concerns

a) Protein Intake: Vegetarians must pay attention to protein sources to ensure they meet their daily protein needs. Animal proteins are complete proteins (they have all the essential amino-acids), but most plant-proteins are incomplete proteins (6).

b) Vitamin B12 Deficiency: Vitamin B12 is primarily found in animal products, so vegetarians, especially those who exclude dairy and eggs, may need to take supplements or consume B12-fortified foods to avoid deficiency (7).

c) Iron Absorption: Plant-based iron (non-heme iron) is less readily absorbed by the body compared to heme iron found in animal products (8).

d) Omega-3 Fatty Acids: Vegetarians may need to pay attention to their omega-3 fatty acid intake, as plant-based sources (i.e. flaxseeds, chia seeds, walnuts) provide a different form of omega-3s than those found in fatty fish.

All of these nutritional concerns can be avoided with a proper, balanced vegetarian diet. Resources on how to start a vegetarian diet are provided below.

Social and Practical Challenges

a) Limited Food Choices: Dining out or attending social gatherings can be challenging for vegetarians, as meat-free options are not always readily available or well-prepared.

b) Family and Cultural Pressures: Vegetarians may face resistance or skepticism from family members or communities that traditionally place a high value on meat consumption.

The Vegetarian Diet and Sports Performance

Due to the many cons of a vegetarian diet, we may wonder if it is a good diet for athletes and sports performance overall. Research is limited on this topic, and the existing studies are not the highest quality.

If you are consuming low-protein, iron-deficient, vitamin B12 deficient, it is absolutely possible to have poor performance in both endurance and strength training. But the same would happen on a poor-quality omnivorous diet (diet with animal and plant-based products).

Overall, it seems that a balanced, optimized, and healthy vegetarian diet (one that has addressed all of the possible nutritional concerns) is no superior or inferior to a balanced omnivorous diet (9).

Resources on How to Start a Vegetarian Diet

Protein Intake

There are a few complete plant-based proteins (quinoa, buckwheat, hempseed, soybeans, tofu, tempeh, seitan, etc.), but these are not enough to meet your nutritional needs.

However, you can consume different incomplete proteins during your day to ensure you are eating all of your amino acids. Some examples include legumes (beans, peas, lentils), nuts, seeds, whole grains, etc. Here is an article with incomplete protein ideas.

Vitamin B12

Adults who are +19 years old usually need around 2.4 mcg of vitamin B12 per day. One egg has 0.5 mcg (~20%), and 1 cup of milk has 1.3 mcg (~54%), and 1 plain yogurt has 1 mcg (~20%). With these 3 products, it is possible to reach the daily need of vitamin B12 (7).

However, vegetarians who exclude dairy and eggs should consider vitamin B12 supplements or B12-fortified foods.

Iron

The RDA for adults 19-50 years is 8 mg daily for men, and 18 mg for women. In this article you will find a list of plant-based sources of iron. For example, 1 cup of lima beans has 4.1 mg (51% of RDA for men, 25% for women).

However, as mentioned before, the iron found in plants is not as well-absorbed. A way to enhance absorption is to include vitamin C-rich foods with iron-containing meals (as in, at the same time). Here is an article with foods rich in vitamin C.

Conclusion

The vegetarian diet, rooted in ancient traditions and driven by ethical, health, and environmental considerations, offers a range of potential benefits, including improved health, reduced environmental impact, and animal welfare promotion.

However, it is not without its challenges, including potential nutritional gaps and social hurdles. Individuals considering a vegetarian diet should carefully plan their meals.

Ultimately, the decision to embrace a vegetarian diet should align with one’s values, health goals, and personal circumstances.

This post was written by Irene Mejia, RD and Sports Nutrition Specialist.