Eating Too Few Calories

It might be difficult for vegans and vegetarians to meet their calorie needs because so many foods and food groups are off-limits to them. In fact, people who eat just plants or are vegetarians or vegans typically consume fewer calories.

In one study, the nutritional value of 1,475 people's diets—including those of vegans, vegetarians, fish-eating vegetarians, people who ate both meat and plants, and those who had meat only once per week—was compared. With 600 fewer calories than those who ate both meat and veggies, vegans had the lowest calorie consumption of all of the groups. Even though vegetarians and vegans consumed somewhat more calories than meat-and-vegetable eaters did, they still consumed 263 fewer calories overall. Your body requires a certain number of calories to function, which is the main source of energy for the body. Overly limiting calories can have a number of detrimental side effects, including vitamin shortages, fatigue, and slowed metabolism.