Close this search box.

The Green Effect: Vegetarians Skinnier, Less Outgoing Than Meat Eaters

By John Anderer

LEIPZIG, Germany — Thinking of going vegetarian? You’re far from alone, and it isn’t all that difficult to figure out why. Meat consumption is linked ad nauseam to cardiovascular issues and other health problems. Conversely, a plant-based diet is seemingly the darling of healthy eating these days. Add in a growing sense of environmental responsibility among consumers, and it’s no surprise that millions try out vegetarianism.

Now, an interesting new study finds that adopting a no-meat lifestyle can impact people beyond just their heart health. Researchers from the Max Planck Institute for Human Cognitive and Brain Sciences say that the less meat a person consumes, the lower their average BMI/body weight. They also say that vegetarians also tend to be more introverted, shy, and reserved than meat eaters.

These associations held true regardless of an individual’s age, gender, and level of education.

Diets were assessed via surveys that asked participants how often they had eaten various animal food products over the past year. Meanwhile, personality traits were analyzed using numerous tests and scientific inventories.

All-natural Americans

As far as why vegetarianism leads to a lower BMI, the research team theorizes it probably has to do with meat products nowadays being so processed.

“Products that are excessively rich in fat and sugar are particularly fattening. They stimulate the appetite and delay the feeling of satiety,” explains first study author Evelyn Medawar in a release. “If you avoid animal foods, you consume fewer such products on average.”

Additionally, typical vegetarian fare usually contains lots of fibers that are good for one’s intestinal microbiome. This can also promote weight loss or a lower overall BMI.

“People who eat predominantly vegetable foods may therefore absorb less energy,” adds Medawar.

Even among those who aren’t following a vegetarian lifestyle, not all animal foods are equal when it comes to a low BMI. Researchers noted that people who eat lots of “primary” animal foods (sausages, meat) usually have a higher BMI than others who stick to mostly “secondary” animal products (milk, cheese, eggs, etc).


“A person with a 1.2 point lower BMI on average either completely avoids certain animal products, such as the primary ones, and is on a vegetarian diet. Or she continues to eat meat and fish, but less often,” Medawar explains.

Vegetarians less socially active

Perhaps most fascinating is that vegetarianism (and veganism as well) plays a large role in one’s personality. Point blank, the authors say people who don’t eat animal foods are more introverted and shy.

“It is difficult to say what the reason for this is,” says study co-author Veronica Witte. “It could be because more introverted people tend to have more restrictive eating habits or because they are more socially segregated because of their eating habits.”

Prior research had found a possible connection between plant-based diets and neuroticism, but this study found no such association.

“Earlier analyses had found that more neurotic people were generally more likely to avoid certain groups of foods and to behave more restrictively. We focused here solely on the avoidance of animal products and could not observe any correlation,” says Witte.

The research team also investigated if being vegetarian often leads to depression, but again, found no evidence of such a relationship.

“We could not detect this correlation,” theorizes theorizes. “It is possible that in previous analyses other factors had blurred the results, including the BMI or conspicuous personality traits that are known to be associated with depression. We accounted for them.”

The study is published in Nutrients.