From environmental concerns to ethical ones, there are many reasons why people choose to begin to pursue a vegetarian diet. However, choosing to become vegan or vegetarian may result in a deficiency of several crucial vitamins and minerals the human body needs.

Oftentimes people are under the impression that eggs, meat and animal fats should be eliminated from our diets because they are bad for us. While vegetarian diets do emphasize the importance of eating vegetables, which are nutritious and good for you, they also emphasize eating a lot of grains and carbohydrates.

Vegan and vegetarian diets are often deficient of B12, calcium, iron, zinc and vitamins A and D.

Vegetarians and vegans may often find themselves easily fatigued and lethargic. They often feel weak and experience memory loss. This is because of the Vitamin B12 deficiency in vegan and vegetarian diets. According to a study by the U.S. National Library of Medicine and the National Institutes of Health, 68 percent of vegetarians and 83 percent of vegans are vitamin B12 deficient compared to 5 percent of omnivores.

B12 is involved with many functions of the body, one being the conduction of nerve impulses.

In addition to B12, vegetarian and vegan diets also lack the proper intake of Calcium. This is true specifically in vegan diets. According to the American Journal of Clinical Nutrition, it would take 16 servings of spinach to get the same amount of calcium as an 8-ounce glass of milk. That would look like 33 cups of raw spinach.

Despite the evidence that vegetarians do not give their bodies enough crucial nutrients and vitamins, many still argue that vegetarians live longer than non-vegan or vegetarians.

While there are studies that suggest vegetarians live longer than non-vegetarians, Chris Kresser, the creator of on of the top 25 natural health sites in the world and the best-selling author of “Your Personal Paleo Code,” attributes the studies to a “healthy user bias,” meaning people who engage in one behavior perceived to be the healthy, whether it is or not, are likely to engage in other healthy options.

Kresser uses the example of vegetarians tending to be healthier than the general population. In addition to being vegetarian, they are also likely to smoke and drink less and likely to get more exercise and eat more fruits and vegetables.

To counter the “vegetarians live longer” comment, Kresser cited a study from the U.S. National Library of Medicine and the National Institutes of Health that, instead of looking just at vegetarians, looked at people who shop at health food stores, both vegetarians and omnivores. The researcher found that both vegetarians and omnivores that shopped at the health food stores lived longer than the people in the general population.

Without strict attention to detail and care, vegetarians are not always receiving the necessary dietary needs that omnivores are. Particularly on university and college campuses, where vegetarian options are scarce, it is easy to skip a serving of veggies and substitute it for an order of greasy French fries.