Justin Bieber tried going vegan at the suggestion of his mentor Usher, but it seems like going vegan also affects his mood greatly as he was called a jerk and a brat.

“His mood took a major nose dive — he was such a brat. Soon everyone was begging him to just eat a steak!,” a source said. “Justin ordered a tofu steak and tempeh tacos from Real Food Daily in L.A. and was just really grossed out He made a big show of spitting out the food and making gagging noises.”

Rumour has it girlfriend Selena Gomez, who at first encouraged the diet change, also told him to start eating meat again as it only made him a ‘jerk’.

Source