I pretty much use GU gels (Plain or Vanilla) on any run over 7 miles.
I ALWAYS take them with water. I actually take a little in my mouth then take a drink to dilute it. That seems to thin it out a bit. Otherwise they are disgusting! I've tired all brands and a lot of flavors. The idea is to just get it in with the least amount of effort.
Duane
I tend to agree with Duane, but the brand I use is crank sports...they have a gel (E-Gel) and a drink mix (E-Fuel). I like them since there are no added sugar, and no Sucralose (an artificial sweeter, basically a genetically modified sugar which hasn't convincingly been demonstrated to be safe...but its in a LOT of "sugar free" products.
You need to always take a gel (regardless of brand) with water (NOT a sports drink), so that the electrolytes are carried to your small intestine which is where they are absorbed...otherwise they will sit in your stomach until you "purge" them.
At a high level, the gels are hypertonic (more concentrated than your body fluids) which slows absorbtion. If you take it with water, the concentration gets closer to your body fluid composition, which speeds absorption. Drinking an electrolyte replacement drink with your gel (instead of water) will not properly dilute the gel, which slows the absorption rate. This can also lead to stomach irritation and a dehydrating effect as your cellular fluids are drawn upon to dilute the gel.
The Crank Sports stuff uses maltodextrin as its carb source...much more complex than glucose, sucrose and dextrin...which means that you get more even absorption of the energy...and avoid energy swings (peaks and valleys, bonking etc).
I have attached a link to the Crank Sports site, and highly recommend these supplements. I'm not a dealer, owner, or anything but a very satisfied customer.
http://cranksports.com/
There is a way for me to get referral credits on my own future orders if you decide to try some, but I don't want to pimp that...if you are going to try it, and feel like letting me get some credit for the referral, please PM me and I'll send you the links.
If not, I STILL highly recommend these....
Mike