Nutrition before and during Olympic Dist Tri

It also depends on how long you plan to be out there as well as how big you are.   Check out the Hammer Nutrition website for suggestions on how many calories per hour.  I tried to take in about 200-250 in my one and only Oly last year.  In hindsight, I probably ate too much before the race, but I felt great during and after.  Had wholewheat bagel and peanut butter and a banana for breakfast with water, a Clif bar after I got to the site... all with water, a gel right before the swim, HEED and one gel on the bike, then some more gel and water during the run.  Sounds like a lot of calories, but like I said, I felt great.  Whatever you do, practice before your race - either on smaller races or before some early workouts.  Good luck and have fun!

Edit - it took me 3 and a half hours to finish

As mentioned above, your nutrition/hydration the day or two before your event is actually what you'll be racing on.  For the race this weekend, the only thing I had on race morning before the race was a piece of toast w/ peanut butter before leaving the house, some handfuls of Kix as I was driving down, plus water.

I don't take a gel before the swim (although quite a few people seem to do so.)  On the bike, I finished most of a bottle of water and about 1/2 the bottle of Amino Vital.  No gels.  I've found that they sit heavy on my stomach and actually make me feel slower.  (Blood diverting to the stomach, perhaps?)  On the course itself, I think many folks tend to take in too many calories for an Olympic distance event.  You've been training your body to use its stored fuel, so let it do so.

I only use water on the run, because regular Gatorade tends to cause cramps, for me.  My other new, favorite advice is: if it is a hot day, wear a running cap (not a visor) and dump ice in it at each aid station.  The melting ice is great for keeping you cooler.  (I don't advocate dumping water on yourself, because you're likely to get your shoes soaked, which is a great way to  get blisters during the run.)

All that being said, it's a whole different story when we start talking about HIM.  For HIM, you probably don't have enough fuel stored for the entire race.