James McAvoy was using protein shakes to bulk up for his role opposite Angelina Jolie in Wanted. But the shakes gave him such horrible gas that he finally had to quit them.
"They really helped - but they do come with the unfortunate side effect of violent flatulence," McAvoy explained.
"I gave up taking them and just tried to eat as much steak and chicken as I could."
I've got all the protein you'll ever need right here James.