Apparently they let you burn more fat than glycogen, saving your glycogen stores for longer.
They burn more fat because you’re not drinking sugar, surely?
Drink sugar – body burns sugar (and its own sugar and fat)
Drink water – body burns it’s own sugar and fat
Drink electrlyte – body burns it’s own sugar and fat for a bit longer as you’re not dehydrateing and getting a constant drip feed of vitmins/minerals/caffeen.
Winter – 2:1 maltodextrin:fructose, pro plus pills, ‘electolyte’, orange squash, hot water
Summer – electolyte + ice cubes + squash + cold water
I find it really hard to judge the energy content in summer so don’t bother anymore, or if I do I guestimate it and then halve it. Getting stuck with too strong a mix isn’t plesent. Whereas in winter I drink less so ~400caloires/litre lasts a whole ride without getting thirsty or a dehydrated sugar rush.