In regards to fasting and its effects on physical endurance:

Back when I was fasting for several days at a time, I did a 33 mile bike ride after 60 hours (2-1/2 days) of fasting. By the time I finished, I was on the verge of passing out, and felt light-headed for several hours afterward. Eating a meal afterward had no immediate effect. I returned to feeling normal after a night's rest.

I just recently did a 45 mile ride after about 18 hours of not eating, and had no issue whatsoever with endurance. Felt great after I finished, and could probably have done another 10 or 20 miles.

So I can say that going a single day between meals, at least when your body is used to it, is not detrimental toward endurance. But if you fast for multiple days, I suggest eating a little something before a long workout.