How many Iron Butt fatalities have occurred? I know how tired I am after 7-800 mile day in a comfortable vehicle. I just do not get it. You need to be healthy and alert but 50 lbs overweight is no big deal. Just an unnecessary risk to what point. People I ride with would probably question my sanity not applaud me.
I can't say none, but the safety record is very, very good. Far better than the average motorcycle community. In part, this is because of the focus on SAFE long distance riding and all the education efforts to teach riders to do it safely. Part of this is listening to you body, establishing bench marks for YOU and how you respond to the process. Keep in mind that a 1000 mile day is only an average of 41.67 mph. Most people take about 18 hours to do a 1k day. That's an average of 55.56 mph. It's not about going fast or depriving yourself of sleep, it's about managing your time and staying on the bike.
Life is full of risks. We don't stop living. What we individually do is manage our risks. Part of that for you may be deciding that there is zero reason for you to go ride a 1k day. Part of that for me is deciding there is zero reason for me to try and ride 30 or more 1k days in a row!
We're all different. That's a GOOD thing. I don't get some people's hobbies like wing suits and drag racing, but to each their own. They don't get my hobby of long distance riding, (I rarely do it any more now, but did a lot over a 15 year period). Unnecessary risk is in the eye of the beholder. Sort of like Art. I wouldn't pay $150k for a banana duct taped to the wall, but someone did. I think they are an idiot. They likely disagree with my opinion on that.
With what I've learned about myself and riding long distances I know my sleep needs and patterns and know I can knock out a 1k day on just about any bike, if I want to. It's a lot more comfortable on a bike set up to be ergonomically dialed in for me, with water and snacks available while moving, but I've done it on stock bikes w/o any of that too. It's not something you just decide to do and go do. Most people work up to the longer days and learn along the way what works, what doesn't and make changes to dial in the bike for their comfort so they can be focused and alert instead of being irritated by some small things that take their focus off the riding. I'm much more comfortable on my LD bike than I am in the car.