Pre-race diet - Around 30 minutes before beginning a race, get one or more "Little Debbie" snack cakes (or equivalent) and eat about 200 - 350 calories worth. In most cases a single package will do. Good choices can include an oatmeal cream pie, a large size fudge brownie, or one twin pack of nuttie bars. This will put a nice concentration of carbs into your blood stream just in time for your event. This also assumes that your event won't be longer than 20 - 25 minutes. For longer events you will have to juggle with your diet some and maybe even eat a second helping in the minutes prior to the event (such as a marathon or 10k run). For really long runs such as a marathon, you will have to consider eating at regular intervals throughout the run, but that's another story.
Pre-race hydration - During longer events you will have to concern yourself with proper hydration so you don't suffer from dehydration during the race. Generally your stomach can absorb about 1 liter of water per hour. Cold fluids will absorb faster than warm fluids so you should always drink cold fluids when possible. A sports drink such as Gatorade or PowerAde is good during and just prior to exercise because they contain a balanced blend of electrolytes and carbs. For shorter events (30 min or less), you are not likely going to suffer from any dehydration from the event itself and you may be better off not drinking in the minutes prior to these events or you might suffer from stomach bloat, which can affect your performance more than being a little thirsty. For these shorter events, plan on completing your hydration fully 30 minutes prior to the event. The idea here is that you want your stomach to be mostly empty come time for the event to minimize any discomfort that may occur.
Protein Drink Powder
Pre-workout diet - Since your workout will typically take much longer than a 3.2-mile race, you will have to concern yourself with food and drink while working out. Generally the same rule for not eating regular foods in the 2 hours prior to your workout applies. As in the race scenario, you will want to eat a high carb snack (200 - 350 calories) about 30 minutes prior to working out. You will also probably want to eat about ½ a Little Debbie snack cake in the minutes just prior to working out. A good time for this is just after your stretches and just before your workout.
Food and drink while working out - During your workout, you should consume a high carb snack of about 150 - 200 calories every 30 minutes or so. In most cases you can achieve this goal by drinking about 16oz of Gatorade or PowerAde and eating ½ a Little Debbie snack cake. You won't want to try to get all your calories from just a sports drink or just a snack cake because you will either wind up getting dehydrated or bloated. You should attempt to strike a balance between the two. Doing this will provide a steady supply of carbs to fuel your muscles while you are exercising.
Post-race or workout recovery nutrition
Perhaps the most misunderstood aspect of fitness training is what to do during the two hours after a hard workout or race. Do it right and you will find yourself ready and refreshed to start your next day's workout with a minimum of soreness and fatigue. Do it wrong and you will be hating every moment of your daily practice and your performance will suffer considerably.
For starters you will NOT want to consume any fat during the 2 hours after your workout! This means ZERO calories from fat. What you want is to consume a proper balance of protein and carbs to stimulate proper insulin production and replenishment of glycogen in your muscle cells.
My prescription is to drink a pure protein drink with about 24 - 30 grams of whey protein powder in it. You will want to use whey protein instead of other types because it has been proven to be the most effective when it comes to muscle recovery. You will also want to be sure that your drink does not contain any other "performance enhancing" supplements because these not only increase the cost of the protein powder but are also useless when it comes to post workout recovery.
Next, you will want to drink about 24 - 32oz of a high carb drink. Excellent examples would include Hawaiian Punch (any flavor), Hi-C Blast (any flavor) or Sam's Choice Lemonade (Wal-Mart). You should read the labels and be sure that the drink has at least 120 calories per 8oz serving. Be careful to avoid the "Low Carb" versions of these drinks and you will find that some of the lemonades will have fewer calories than their fruit flavored counterparts.
Do not even think about consuming Gatorade or PowerAde for your post recovery drink. The reason for this is that they are quite low in carbs (typically about 50 calories per 8oz serving) and while this is ideal for during a workout, this is not anywhere sufficient for a post recovery drink. Think about it, you will want to consume about 400 - 500 calories of carbs during your post recovery drink and trying to do this using Gatorade will require that you drink something in excess of ½ gallon in less than an hour. Unless you are a camel by design, this will probably have you barfing all over the place before you even get through!
The idea here is that you will be wanting to speed the maximum amount of carbs into your bloodstream so that insulin can convert these carbs into glycogen and infuse this glycogen back into your muscle cells as quickly as possible. It has been proven that there is a 2 hour window of opportunity immediately after a workout where your body will perform this task at its fastest. Wait 'til after this window of opportunity and it might take a couple of days or more for you to fully restore this lost glycogen, so you can see that time is of the essence!
Whatever amounts of protein drink or carb drink you consume, it is very important that you maintain the proper percentages of protein vs. carb when you do this. You will want this to balance out at 20% protein and 80% carbs (by weight in grams). In the above example you will see that the 8oz protein drink made from one scoop of whey powder (24 - 30 grams of protein) is in proper proportion to the 32oz of Hi-C drink (about 100 - 125 grams of carbs). Obviously you will have to play with the proportions a bit to compensate for the fact that the actual amount of carbs varies from drink to drink but the math is quite simple to figure in your head.
The scientific reason for the above proportions is that it has been proven that adding a 20% protein mix to your carb intake will just about double the insulin response in your body. This is critical in that it is this insulin response that performs the actual conversion of carbs into glycogen and injects the glycogen straight into your muscle cells. It has also been found that fat will inhibit the insulin response and poor glycogen recovery will be the result.
In addition to the above mentioned drinks you might want to consider taking a couple of multi-vitamins to replenish critical elements to help with muscle regeneration. For your evening meal you should try to eat more complex carbs in the form of pasta, rice, breads or cereals. Balance this with a serving of protein in the form of chicken, fish, or beef as well. For your breakfasts you should eat a balanced blend of carbs and protein. Healthy examples include bagels, eggs, cereals, toast, sausage, bacon and the like. Avoid sugary breakfasts such as Fruit Loops or Pop Tarts. Also, you may find that too much in the way of fresh fruit or fruit juices can cause stomach cramps and diarrhea, which is no fun. Only you will know whether you can handle large amounts of fruits as part of your diet. You should also fill out your diet with a good mix of vegetables as well.
Generally, you will want to make complex carbs as part of your meal plan for breakfast, lunch, and dinner. You should only target the simple carbs (snack cakes and fruit punch) for the time period surrounding your workout. Follow these guidelines and your athletic performance will be better than you can imagine.