Matthieu Ricard is a 71 year old Buddhist monk who, scientifically, is the "happiest man alive". He believes that is because ofhim being vegan:
"True happiness can only be attained when we avoid causing pain to others, so please become vegan like me."
So, how did someone decide that he's the happiest man?
"He participated in a 12-year study where MRI scans revealed that his brain had the highest level of gamma waves that had ever been discovered in scientific studies. Since gamma waves are associated with happiness and feeling blessed, he earned his nickname."