LAS VEGAS, NEVADA - MARCH 04: Conor McGregor of Ireland stands on stage during the UFC 196 weigh-in at the MGM Grand Garden Arena on March 4, 2016 in Las Vegas, Nevada. (Photo by Jeff Bottari/Zuffa LLC/Zuffa LLC via Getty Images)Jeff Bottari/Zuffa LLC/Getty Images

Weight cutting is a brutal process and few fighters have shown that like Conor McGregor. The UFC featherweight champion has left his division behind in recent months in his rivalry with Nate Diaz (with both fights being contested at 170 pounds), who is competing close to his natural weight. The side-by-side of a hydrated and healthy McGregor and the withered version last seen at the UFC 194 weigh-ins is a jarring sight. 

Here is McGregor at Friday's weigh-ins:

LAS VEGAS, NV - AUGUST 19: Conor McGregor of Ireland poses on the scale during the UFC 202 weigh-in at the MGM Grand Hotel & Casino on August 19, 2016 in Las Vegas, Nevada. (Photo by Josh Hedges/Zuffa LLC/Zuffa LLC via Getty Images)Josh Hedges/Zuffa LLC/Getty Images

And here's a shot of McGregor at the open work-outs on Thursday:

LAS VEGAS, NV - AUGUST 18: UFC featherweight champion Conor McGregor takes questions from the media during an open workout for UFC 202 at Rocks Lounge at the Red Rock Casino on August 18, 2016 in Las Vegas, Nevada. McGregor is scheduled to fight Nate DiaEthan Miller/Getty Images

This is basically the McGregor that most fans know now, and it's a McGregor that looks the part of an excellent fighter.

Brett Okamoto @bokamotoESPN

McGregor weighed in 168 for both UFC 196 and 202. Looked much better on scale today though. He was bloated 196, looked fit today.

One could also make the case that he looks better than the McGregor that showed up at UFC 196:

Mar 4, 2016; Las Vegas, NV, USA; Conor McGregor during weigh-ins for UFC 196 fight against Nate Diaz (not pictured) at MGM Grand Garden Arena. Mandatory Credit: Mark J. Rebilas-USA TODAY SportsMark J. Rebilas-USA TODAY Sports

McGregor wore his muscle at 196, but looks a bit leaner for 202. That's an important note as he chalks up his UFC 196 loss to a lack of cardio. He wouldn't be the first fighter to have his performance suffer from a lack of discipline after moving up in weight.

This brings us to the 145-pound McGregor that showed up at UFC 194:

LAS VEGAS, NEVADA - DECEMBER 11: UFC featherweight champion Jose Aldo of Brazil (L) faces off against Conor McGregor of Ireland (R) during the UFC 194 Weigh-in event at the MGM Grand Garden Arena on December 11, 2015 in Las Vegas, Nevada. (Photo by JeffJeff Bottari/Zuffa LLC/Getty Images

The difference is plain. His face is shrunken in, his torso is sunken and he's considerably less muscular. It's an ugly sight and a testament to the amazing lengths that fighters have to go through to cut weight.

John Locher/Associated Press

Worth noting is that McGregor's future most likely lies outside of the welterweight division. But it's unclear if he will, or even can, go back down to 145 pounds. That makes his weight an important factor to watch in the coming months.