I ran my 26km with an empty stomach initially, but I took 1 gel 11km in, hydrated 5 sips of water 3x during the run. Still considered underfuelled and underhydrated. Will be increasing my gel + water intake, I might try one slice of bread to see how it goes before the next long run lol
Can watch this vid from Holly Archer for some info and new nuance on fuelling. But of coz she is an elite and she has trained to handle that rate and our amateur needs are different. But still, useful to know in case you or someone needs this specifically for their long duration race........
For me, i guess still no reason for me to fuel similarly as i dont race such long distances nor the workouts.
For me and my kid it's just a way to prevent bonking....as my kid has indeed bonked a couple of times, once serious enough that he had to sit by the roadside to rest as he said "not feeling well" while i cycled to the coffeeshop to get sugary drinks. There is a small chance that we could get into an accident coz of this, all the way from just a small crash coz ownself fall down due to incoordination or not noticing bumps, all the way to falling down right in front of a vehicle however rare that might be.
The crossover point from using predominantly glycogen to fat stores with intakes of 60, 90 and 120g/h.
She felt the best with 120g/h. She is ex decathelete, present (EU, national) elite grade runner and Hyroxer, iirc 32 min 10k and first FM last year 2:39.
Quote :
At 120g per hour, I experienced:
✔ Lower perceived effort (RPE)
✔ Better perceived energy levels
✔ Improved fluid retention
✔ Less body mass loss
✔ A delayed shift toward fat oxidation
This matters because carbohydrate produces more energy per litre of oxygen than fat, making it the more efficient fuel at marathon pace. When fuelling at 60g per hour, I lost 1.4kg of body mass, likely mostly fluid, and showed an earlier shift toward fat use, meaning less efficient energy production for the same effort. This is why fuelling shouldn’t be guesswork.
ps. Some might note that is for Holly, an elite fast athelete. The researchers noted that it's the same or even more important that average athletes fuel the same, coz they are out there on the course for even longer, so delaying that carb -> fax oxidation switch point till a latter stage is even more advantageous. 
