Conor McGregor Is on Steroids After UFC 196 Weight Gain, Says Nate Diaz's Coach | News, Scores, Highlights, Stats, and Rumors

I sure do believe that [he's on steroids], heck yeah. Some guys, they get busted - and to be honest with you, I know McGregor has got to be on some kind of steroids. He’s pretty big, and then all of a sudden [he’s] jumping to 170? Yeah there’s no way, because I mean, he was supposed to be fighting at 155. 

So if you think about it, he was focusing on training at 155. He only had two weeks to go. And all of a sudden he’s gonna jump to 170? So no, there’s something going on.

When Nathan mentioned it to him, he got defensive, he got angry. If somebody would have told me that I was fighting and he told me, you know, steroids, I would laugh and say, "yeah give me some more steroids, heck yeah, ah ha sure." But he got defensive and mad, you know, "I’m not on steroids, I’m not on steroids!" You know, he was like trying to defend himself. So that, just his actions and the way he talked, there’s something behind that.