Yeah, not to derail the thread but I'm aware of the signature image tab in vv.
However, on BF within the settings of my signature permissions, it seems like image incorporation through URL or BB is not available to me.
And to contribute something more, I say drink and drink is the key!! As for the sugars, I usually have a 600ml bottle of strong, undiluted juice in a jersey pocket and ~100g of dates and a few mini-packets of Skittles or Haribos. As long as water is unlimited, that'll always get me to 300km. However, Probably would have to double that to get 300km with 5000m climbing.