An old running adage is "don't try anything new on race day." This definitely holds true for your pre-race meal or snack. Everyone is different with this, so figure out what works for YOU, just don't figure it out on the day of your race! A more intense workout during the approximate time of your race (whether AM or PM) provides a prime opportunity to test out your race plan. Once you find your individual optimal pre-race meal, stick with it. Case in point: I've included Nature Valley granola bars in my pre-race meal since at least 2003.
Everyone is very individual with this. I know runners who like to eat 5 hours before race start, but I would be starving and cracked by mile one if I did this. (I did know one guy who actually liked being literally hungry on the starting line...as opposed to figuratively hungry, which hopefully goes for everyone.) I like to eat my last pre-race meal two hours before the time of race start. For some people, this might be too close, but I've been doing this for more than a decade and it's the optimal race strategy for me. The good news to take away from this is that once you do figure out when you should eat your prerace meal, that time should stay relatively consistent.
For all of my morning races of half-marathon distance or shorter, I have what I call a "peanut butter banana" and a Nature Valley Crunchy PB granola bar. I take a banana, slice it lengthwise and spread a not overly abundant amount of organic peanut butter on it, before slicing it again into "pennies." I also add more peanut butter to both pieces of the Nature Valley granola bar (always to the same side that already has some PB on it. If this sounds rather exact, it's because I allow myself to be superstitious about my pre-race food. I used to think the NV granola bars that came stuck together within their two-packs were lucky and I'd always eat these ones if possible. I'm actually fairly certain that I've bought a new box of these just to find a pack of "stuck together" ones.)
Keep in mind that a race in the morning may require different nutrition than an evening race. I know I generally tend to digest faster in the morning; on a regular early morning run, I can eat a banana or Luna bar and head straight out the door. (Also be aware that your stomach is going to react differently to a race than a normal low-key run. That's why it's best to test out your pre-race nutrition before a big workout.) For evening races, having less in the five hours before the race tends to work well for me. I stick with my usual morning race routine, but then also have something like a turkey sandwich 4 or so hours before race start. In college, for evening races, I used to have a Subway sandwich around 4 hours before start. Subway worked great because I could always find one when we traveled! If you can keep the pre-race meal simple, you can focus on everything else important before the race.
Good foods for pre-race...and ones to avoid.
Bananas! Easy to digest. Basically the perfect all-around food if you had to choose just one item to exist on for the rest of your life.
Peanut butter in general works well as a pre-race food. In high school, I had a teammate on my USATF Pacers Track Club summer team who always had a spoonful of PB before her races since she thought it kept her stomach calm and stuck with her. This is actually what got me hooked on PB! When my mom races 5ks, she has a few peanut butter crackers from those six-packs of crackers easily found in the grocery store. I know many runners who have peanut butter on a bagel before a race. In college, I did something similar: I kept the NV granola bar as part of my pre-race meal plan, but instead of the PB banana, I had peanut butter toast. Toast worked much better for me than anything untoasted, which could feel too "doughy" in my stomach before a big event. Toast of course is trickier since toasters are not always readily accessible if one is on a team bus, or otherwise away from electricity two hours before the start of the race. I went through all sorts of challenges getting that toast ready to bring with me during my DI college running days... I also once went back through airport security when heading home from Big East for track so that I didn't have to sacrifice my newly bought jar of organic PB due to the "4 ounces of liquid" carry-on rule. Me to security: "But peanut butter is not a liquid!" The experience of saving my PB was about as heart-pounding as my race because my coaches would not have been happy about my PB rescue mission.
Protein bars or granola bars of various kinds can work well as a pre-race snack. Again, just be sure to test the specific flavor which you'll be using. Don't toss down an expresso-flavored bar when you normally avoid coffee.
Apples are NOT good for pre-race. I learned this the hard way throughout high school...just don't do it, because that's going to come right back at you during the three-quarters mark of that race. Citrus fruits can also have a rather rough effect on the stomach. Save the oranges and orange juice for after the race.
Quantity...with a Digression on Water Stations
I eat the same amount (pb banana + NV granola bar) for all races except the marathon. For the one marathon that I've run (Kiawah Island, 2012), I knew I'd need more than the usual pre-race to get me through all 26.2 miles, so I added oatmeal to my normal pre-race meal. I kept my timing of my meal the same.
The marathon also involves quite a bit of planning of on-course nutrition, both in terms of liquid intake and items from the GU/Shotblock family. I'm still figuring out how to do the whole GU thing, but I've gotten much better at grabbing water and Gatorade cups along course and not spilling them all over myself! This is truly something you should practice on your long runs, because it's quite frankly not as easy as it sounds. (I've had full conversations with other runners about grabbing liquid nutrition during races. "But the water cups were only a sixth of the way full!," "I didn't get any NUUN up my nose this time!," etc.) Typically, on race day for a half or marathon, volunteers will be at various mile markers holding out water and Gatorade cups for you. If possible during your long runs, you can practice this situation by putting out Dixie cups of the race drink at some handy spot at hand-level. Even if not possible to practice this, you can do other things during the race to make sure the water station volunteer is "ready" for you when you approach! Specifically, I suggest the following plan of attack while racing:
1. Check out the upcoming drink station and see which volunteers look alert. If possible choose one at the front of the volunteer group so that you may have a second chance to grab a drink if you miss. 2. Make DIRECT eye contact with your chosen person so he knows you are thirsty, and coming for him! 3. Cup your hand in a visible "C" shape as if you were about to grab a cup. This is less to help you grab the cup (though it does help!) as it is to let the volunteer know you are after the actual cup that he is holding. 4. Once you've got the cup, keep running. Do not stop to drink; besides slowing yourself down, you may have someone running up right behind you at the water stop. 5. Sometimes you can "dent" the lip of the cup to make it easier to drink from that edge. Keep hold of that drink until you've successfully had some! Consider pouring extra over your head if necessary to cooldown (note: this works better with water than other sports drinks for obvious reasons, though I admit I've finished a race uncomfortably drenched in Gatorade).
While a nutrition plan is important, being flexible is also key! If you feel like you need an extra half of a granola bar or something else on race morning, allow yourself to have some wiggle room to listen to your body. Flexibility also helps when you are left with fewer options on race day, because the less you stress the faster you run! For example, in high school at the Baldwin Invite (if you're from Western PA, you know this meet), I ran my fastest 800 on a McDonald's grilled chicken sandwich that my mom went out to pick up for me. McDonald's was the only thing close to the track that was open, offered fairly simple fare, and would not take long to provide food. (For what it's worth, for evening track meets in high school, I also had great success with chicken teriyaki from the South Hills Village mall food court as my "pre-race.")
This is why it also helps to have a larger family of foods that you know will work fine in your stomach before an intense effort. You can then pack spare granola bars or other good race foods (though probably not chicken teriyaki) so you're fully prepared for whatever can come at you on race day.
Post race meals of course, are a different matter. Below, I leave you with my postrace meal from the 3200m at the 2001 National Junior Olympics in Sacramento: chocolate cake and a chocolate milkshake.
And because some things really never change: here I am after running 18:28 at the Freedom 5k with a double chocolate Dunkin Donut.