Howdy HawkBill
Eating before a hike is very individual. I usually don't eat before Skyline (or have a banana at most) due to the early start.
I recommend not consuming any new foods or fluids before a big hike, marathon, 100 mile bike ride, triathlon, etc. You don't want to discover on the trail that your gut didn't tolerate your breakfast
Pre-hike fueling:
After the overnight fast, your liver glycogen (source of blood glucose) is nearly exhuasted. Fueling before helps to maintain your blood glucose.
Some ideas for pre-hike fuel one to two hours ahead of time (assuming you can tolerate food that early):
Oatmeal or other hot or cold cereal with fruit and milk
Boost or other canned liquid food (Ensure)
Breakfast bar or sports bar
Carton of fruited yogurt
Carbohydrate gel and 16 oz. sports drink
If you can't eat before hiking, another strategy is to consume 16 to 32 ounces of a sports drink or eat a carbohydrate gel immediately (5 minutes before) starting. Physiologically, this is similar to taking in carbohydrate during exercise.
Most endurance trained individuals can fill up their muscle glycogen stores by resting and eating a carbohydrate-rich diet several days before "the event." Endurance training increases the ability of the muscles to store glycogen. Resting ensures you're not using up what you're trying to store.
Fueling during the hike:
Skyline is not a competition but I recommend the same stratgies I provide to endurance athletes to protect health and increase the enjoyment of the hike. Most people don't enjoy hiking when their blood sugar is too low and/or they are dehydrated.
Amount of water (the most essential nutrient for Skyline). Depends on your sweat losses. Drink to minimize your sweat losses. Normally, I would have you do a sweat rate test to get an idea of how much water you're losing per hour of hiking.
For the first Skyline, be on the safe side and carry four to five liters/quarts.
Consuming carbohydrate helps to provide glucose for your muscle when they are running low on glycogen. Start fueling 30 to 60 minutes into the hike. Sports drinks have the advantage of providing water, carbohydrate and sodium. You can also obtain carbohydrate and sodium from carbohydrate gels and then drink water to replace fluid losses.
Amount of carbohydrate -- research shows that consuming 30 to 60 grams of carbohydrate per hour (120 to 240 calories) enhances endurance.
Sodium -- depends on sodium losses in sweat. I lose a lot of sodium (shirt is covered with white stuff), so I drink Gatorade Endurance which provides 800 mg of sodium per quart (about the average amount of sodium lost in two pounds of sweat). Powerbar also makes a higher sodium sports drink.
If you're not using a sports drink, consider using an electrolyte replacement product like NUUN or carry salt tablets that provide a decent amount of sodium. You can also take those little fast food packets of salt for emergenices. Endurolytes don't have enough sodium. Muscle cramps are due to sodium losses, not potassium.
Miles of smiles,
Ellen -- yes THAT Ellen
Two time finisher of Hawaii Ironman triathlon (before the back went to hell) and sports dietitian