Our bodies have developed this close working relationship with the bacteria in our gut, and that bacteria can influence what we crave, says Michael Schmidt, PhD, professor and vice chair of the department of microbiology and immunology at the Medical University of South Carolina. He cites a recent study published in the journal BioEssays that found bacteria in our gut will signal to our brain that we need chocolate in order to proliferate, and theorizes that the same could be true for meat. (He says that well likely see research on that hypothesis soon.) For example, if your body is low in iron and the dominant bacteria in your gut need it to survive, you may experience a craving for red meat.
Schmidt stresses that its possible to be healthy on a cellular level on a vegetarian or vegan diet. The human body and the bacteria in us have been optimized to eat whatever we feed it, he tells Yahoo Health. However, he notes that many vegetarians and vegans who feel unhealthy or experience meat cravings may not be getting the proper nutrients they need, and can even become malnourished.
New York-based nutritionist Beth Warren, RD, agrees. Vegetarians and vegans are particularly at risk of deficiencies in vitamin B12 (which are mostly available in animal proteins) and protein if their diet isnt balanced, she tells Yahoo Health. B12 is especially crucial because a deficiency can impact the immune systems function and even lead to pernicious anemia, a decrease in red blood cells that provide oxygen to the bodys tissues. Warren also points out that fatigue and an overall feeling of weakness can occur for vegans and vegetarians if they dont get enough iron in their diets.
https://www.yahoo.com/health/why-some-vegetarians-start-craving-meat-117526618072.html