|Lani looking a little uncertain before the Tremblant|
First and foremost, it is important to know that you will not be able to replace all of the calories, fluid and electrolytes that your body loses during your activity. Your body simply can't process food as quickly as it is burned, so inevitably your body will call upon its reserves to make up the difference. Consuming excess calories, water and electrolytes will not help you: it can actually work against you. So, with that said, here is what I have found works well for me.
#1) Carbohydrates- essential for me for any length of time over 2 hours. You can probably skip feeding for the first hour or so as your glycogen stores will likely carry you through this first hour to two hours. At 5'4" and 120-125 lbs, I generally find I can process about 150 calories in an hour. If it is really hot or I am working really hard, sometimes a little less. During an hour of less exertion, I might be able to sneak 200+ calories without distress.
Some people prefer to add carbs to their water- aka. sports drinks. These have the same effect, but be careful of the ingredients. Simple sugars process fast and can lead to a crash, while those with complex carbs process slower. I generally look for maltodextrin here as well. Hammer, Gu, Clif, etc. all seem to be making similar products these days. Additionally, many products that come premixed (like Gatorade) contain too much sugar per oz of water. You need water to digest sugar, and a ratio too high in sugar can prevent the body from processing excess sugars. If you must use a premixed simple sugar sports drink, consume equal parts of water with it and be prepared for blood sugar spikes 30-45 minutes later.
#2) Protein- For any event longer than 2 hours of exertion, you need to consider adding protein to your nutrition. At about 2 hours, your body will need amino acids. Without protein in your diet, lean muscle tissue can be cannibalized by your body to release these amino acids. To simplify, this will make you feel yucky and your legs heavy. There are lots of options for protein. If gels work for you, one gel that contains protein is Accelerade. Hammer also makes a couple of powders that can be added to a sports drink or consumed with water that I like: Sustained Energy and Perpeteum. Lots of endurance athletes I know prefer to consume their protein as real food including nuts, peanut butter sandwiches, energy bars, etc. Again, what tastes good is usually your best bet, but you want to make sure that protein is on the menu if you will be out for a prolonged time period. I go with 8 grams or so of protein per hour and that seems to work OK for me.
#3) Electrolytes- a must have to avoid muscle cramping. In hot weather you'll need more, but even on cool days electrolytes are needed. Lots of companies make a capsule electrolyte like Endurolytes and S caps. Others have them in sports drinks already. If you are going to rely on a sports drink, make sure yours has sufficient electrolytes alone. If they don't, you can also add powdered electrolytes like Nuun or powdered Endurolytes. The amount depends on the product you use and the electrolyte profile it contains. Generally, the product information will help guide you to a guideline for quantities that you will need.
#4) Proper hydration- regardless of duration, your body can't process food without water. How much will depend upon your size, needs and the climate. Generally, I find about 24-32 oz per hours works for most people under most circumstances. Overhydrating can cause unwanted problems just as dehydration, so be sure to train with water to learn to understand your body's water needs.
#5) Other stuff- for particularly long endurance events (over 24 hours), I have heard many athletes say that they feel that they need solid food. While there is no real scientific basis for this, a psychological component can be equally pressing. Here are some ideas that I have found are great additions when you are really in it for the long haul.
ENSURE- its not just for grandma. With nearly 250 calories and 10-15 grams of protein per tiny bottle, it is a fast way to get added calories, protein and vitamins with very little preparation, effort or stomach distress. I always knew my grandma was on to something. And it doesn't taste half bad.
Salted potatoes, salted beets, pretzels and bananas- all are good sources of carbs and easy to digest, and beets provide additional nitrogen which is thought to be really helpful.
Peanut butter and jelly sandwiches, granola bars, energy bars, nut mixes- all have a nice mix of carbs & protein- a mini meal in one!
Branched Chain Amino tabs- many athletes I know use these to supply additional amino acids during or after long periods of exertion to avoid lean muscle cannibalization.