This past weekend i rode the “tour de cabot” which is an organized ride where our gear was trucked from campsite to campsite.
Three days, 300 km and 4086 meters of climbing recorded.
On a fatbike, loaded with a ton of extra gear and weight.
Fasted exercise only - OMAD, supper.
As long as i stayed below anaerobic level i was able to motor along all day. No need for stops other than to refill my onboard water and reload electrolytes.
Running on fat is the ultimate secret weapon!
I was the only one of 26 riders not filling up on big breakfasts, filling pockets with bananas and energy bars to make it until a huge lunch and repeat.
These people were literally not able to function more than 30 minutes without another hit of carbs.
I dont see keto dietary limitations as restrictions -they are really quite liberating! 
Note: my longest ride this year before this weekends activity was 40km. Most of my rides are 16-20km
Also worth noting is how well i have recovered from my dog attack while riding back in June (collapsed lung and 8-9 ribs broken in 15 places). I was riding to work within 4 weeks after that.
I think keto helped there too.