Rex Ryan and Rob Ryan are brothers. You probably knew that, especially now that Rob has joined Rex's staff in Buffalo. And while they're twins, you can easily tell them apart because Rob is the one with the long hair and the potbelly.

Rex had lap band surgery several years ago and at one point he said he had lost more than 100 pounds. But working with his brother has its downsides when it comes to healthy living.

ESPN's Elizabeth Merrill explains in this profile of the Ryans:

Before we can begin, Rex and Rob Ryan must finish their nature walk. It involves five middle-aged men, all Buffalo Bills staffers, and lasts about half an hour. Rex organized the daily jaunt because he says he has gained 30 pounds since his brother joined the coaching staff this past winter.

There's more:

Rob Ryan, at least initially, was not as passionate about this whole health kick. Back in December, a month before he was hired, Rob visited Buffalo with one of the Ryans' childhood friends, Chuck Abate. Rex is really into salads, and he insisted that they join him for his daily lettuce lunches. Rob and Chuck reluctantly agreed, but then sneaked over to the team cafeteria and scarfed down a premeal meal before they met Rex.

"You guys," Rex told them midsalad, "are doing so good."

Fat or thin, the reality is that this could be the Ryans' final season in Buffalo if the Bills don't qualify for the postseason for the first time since 1999.

In January 2015, shortly after Rex Ryan was hired, he proclaimed that "The last team I'll ever coach will be the Buffalo Bills." That can be interpreted two ways, and by December, with one game left in the season and the Bills sitting at 7-8, Ryan conceded that sometimes "I let my mouth get ahead of everything."

It was enough for Bills legend and Hall of Famer Jim Kelly to note that Ryan will probably be out of work if Buffalo misses the playoffs in 2016.

The head coach is under no illusion about his fate.

"We had the courage to coach together knowing if it doesn't succeed, who's the blame going to?" Rex told Merrill. "The blame is going to be saddled onto two people for an entire organization."

Meanwhile, the defensive assistant sounds unfazed.

"That's fine," Rob added.

As long as the Bills win, yes, it is fine. But the team faces long odds in a division with the Patriots and Ryan's former team, the Jets, who went 10-6 last season.

By the way, if you think Rex has changed after his "I let my mouth get ahead of everything comments" from late last season, he hasn't. If anything, it just sounds like he has a better sense of his audience.

"That doesn't mean he's not saying it to us," Bills center Eric Wood said Ryan's grand proclamations. "I don't reveal what we say in team meetings, but I'll just say we're just as confident as we've ever been as a football team. We still have lofty goals for our team."