I believe theres some science behind the insulin sensitivity, it makes sense as you're not having to control blood sugars constantly compared to eating every 2-3 hours
Endurance I would say is more person specific, at least at our level of sport
For me, I dont like doing anything on a full stomach, I like training fasted and if I've eaten I wait about 3 hours
Some people cant train until they've had 4 meals
The muscle building and body composition thing I'm not sure
I bought into it a little when I did the 16:8 but didnt really notice much difference, at the end of the day
Eat too much and you'll gain weight, too little you'll lose, regardless of fasting
Theres always 2 sides of the argument that both sound convincing
I've been watching a lot of YouTube this lockdown and the importance of regular nutrition and training methods to maximise blood flow
Again, at our level, its purely for enjoyment so do whatever makes you feel the best
If you feel good you'll perform better regardless
Pointless following a plan if you feel like crap and cant be arsed
I did notice oddly my last run i did afternoon with food in and the previous fasted..
Fasted felt easier