We recommend using one or more gels on all of your long runs in preparation for a marathon. Our general rule of thumb is to consume no more than one e-Gel pack every five miles. If you run 6 minute miles, you would consume no more than one every 30 minutes. If you run 12 minute miles you would consume no more than one per hour, etc. However, if you are not able to maintain the recommended hydration plan during the run, then you should reduce your gel intake accordingly.
Hammernutrition.comConsume 1-3 servings per hour (see chart below) along with 16-28 ounces of plain water per hour from a separate source.
Suggested Doses by Body Weight*:
Up to 120 pounds: up to 2 servings/hour
120-155 pounds: up to 2.5 servings/hour
155-190 pounds: up to 3 servings/hour
190+ pounds: up to 3.5 servings/hour
*These are estimated doses. Each athlete should determine in training, under a variety of conditions, their personal optimum.
Marathon Gel & Calorie Calculator I plugged in my numbers and the calculator recommended the first gel at 9 miles, then every 6 miles after.
runnersworld.com article titled "Carbs on the Run"
Jackie Dikos, R.D., a consultant dietitian who heads Nutrition Success in Indianapolis, suggests that runners start "fueling before the onset of fatigue." That means you should start taking in carbs between 30 and 60 minutes into your workout or race, depending on the intensity of your run. Dikos, who ran in this year's Women's Olympic Marathon Trials, starts drinking a carb-rich sports drink about 40 minutes into a marathon. You should then continue fueling in frequent, small doses. The ideal is 100 to 250 calories (or 25 to 60 grams of carbs) per hour, after the first hour of running, says Nancy Clark, M.S., R.D., author of Nancy Clark's Food Guide for Marathoners. That's the equivalent of one to 2 1/2 sports gels or 16 to 40 ounces of sports drink per hour.
In the post below, Owen Anderson recommends 30 grams of carbohydrate per hour. That would be 120 calories, or slightly more than 1 gel.
MY COMMENTS: Looks like everybody has an opinion- I like to take 1 gel with water every 30 minutes- replacing close to 200 calories per hour. That would be 5 or 6 gels in a full marathon. Like anything else, try it in training before you do it in a race.