Mischa Barton, the actress who took off with the hit series "The O.C.", was able to stay fit and toned even through the holidays thanks to running and a healthy vegan diet. But could following a vegan diet really give someone a body like Barton's?

Barton has been telling her friends that she was able to achieve her fit and toned body by "eating really healthy, keeping mostly a vegan diet and running," the New York Post reported. That being said, the vegan diet has been proven to shed off the weight and to keep it off as some other actors have done, like Alicia Silverstone and Pamela Anderson.

Veganism is essentially not eating any foods of an animal origin - not even honey, eggs, or milk. There lies its difference from vegetarianism, which is open to some animal products. However, for those who are really concerned about animals and the environment, and not just looking so slim down, veganism could be a lifestyle that will also not use animal products for clothing and any other purposes.

But living without animal products does have its benefits. Studies have shown that consuming animal products, specifically fats and proteins, raises a person's risk of developing cancer, diabetes, rheumatoid arthritis, hypertension, heart disease, and other such illnesses and conditions, Medical NewsToday.com reported.

In fact, benefits of following a vegan diet extend as far as stopping or reversing the progression of early stage protaste cancer in men, according to a U.S. study that found red meat and processed meat eaters died prematurely more frequently than other people.

With such a restrictive diet, what can vegan followers eat? According to WebMD.com, the diet has plenty of high-fiber, natural fruits, soy products, and vegetables. Among the foods that one can eat are organic fruits and vegetables; soy products, beans and nuts; organic canola, olive, and sesame oils, and coconut oil; whole-grain and whole wheat foods like bread and pasta; tortillas; and brown rice.

And with such an assortment of foods, the diet book infamously named "Skinny Bitch" by Kim Barnoin, said that there's no calorie counting to worry about with a vegan diet regimen.

But the problem with a diet that does not touch with animal products is the fact that a person can miss out on some essential vitamins and nutrients thereby risking deficiencies. According to TheSweetBeet.com, vegan diet lacks things like Vitamin A, technically speaking, B12, Vitamin D, and protein because these only come from animals and their products.

That is why according to experts, a person following a vegan diet will lose weight, this is mainly because it is low in calories. While the American Dietetic Association does approve of a carefully planned vegetarian and vegan diets, one should always first consult a registered dietician to be sure.