Let’s say you weigh 180 pounds, and you have one hour before the run will begin. 180lbs x 0.5 = 90. 90 x 1 hour = you need to eat 90 grams of carb to fuel your run. In your case, you have only half an hour. So your equation will look like this:
http://www.runnersworld.com/fuel-school/how-do-i-fuel-for-an-early-morning-run
I normally run on an empty stomach for distances up to four miles without problems, but after that, I begin to feel the lack of energy. I do feel more energized after eating a sports bar, but I wait an hour before running to give it time to digest.
http://www.runnersworld.com/fuel-school/how-do-i-fuel-for-an-early-morning-run
Article added October 24, 2014 Categories Nutrition, Nutrition Essentials, Uncategorized. I’VE READ ARTICLES that say you shouldn’t eat a large meal (more that 200-300 calories) before a run. They never seem to mention how long you should wait to run if you do have a large meal. Good point! Let’s define “large meal” as a meal containing more than 600 calories with several ounces of protein or meat, carbohydrates, vegetables, and dessert—a typical dinner or large lunch. If you have a meal like this, you should wait three to four hours before running.
http://www.runnersworldonline.com.au/long-wait-run-eating/
Let’s say you weigh 180 pounds, and you have one hour before the run will begin. 90 x 1 hour = you need to eat 90 grams of carb to fuel your run. In your case, you have only half an hour. 90 x ½ an hour = you need to eat 45 grams of carb to fuel your run.
http://www.runnersworld.com/fuel-school/how-do-i-fuel-for-an-early-morning-run
When trying to determine how much fuel to take in before a long run (longer than 75 minutes) begins, the general rule is to consume approximately 0.5 grams of carbohydrate for every pound of body weight and then multiply that number by the number of hours you have before you will begin your run.
http://www.runnersworld.com/fuel-school/how-do-i-fuel-for-an-early-morning-run
How long you need to wait before exercising after eating also depends on the intensity of your workout. You should give yourself longer to digest if you're going to be working out intensely (running, aerobics, etc.) than if your workout will be more gentle (walking).
http://www.sixwise.com/newsletters/07/05/08/eating-and-exercise-should-you-eat-after-exercising-before-how-long-and-what.htm
You should wait to exercise if you've eaten a large meal (at least three to four hours, but sometimes up to six, is required). This is because it takes your body some time to digest a large meal, but intense exercise slows your digestion (and instead diverts energy to your muscles). The result could be cramping, an upset stomach and diarrhea. If you've eaten a small meal, you should still wait two to three hours before working out intensely. Experiment with snacks. For some people, a small snack (like a banana) right before, and even during, exercise provides an energy boost. For others, it can make them feel lightheaded.
http://www.sixwise.com/newsletters/07/05/08/eating-and-exercise-should-you-eat-after-exercising-before-how-long-and-what.htm
I personally like to wait at least an hour and a half before running. You probably could do alright with one hour, though. If you have a race or something like that, I'd suggest two hours and that nothing you eat during that day is hard on your stomach. Two hours is definitely be plenty of time for all of your food to digest, as long as you don't have too large of a meal. I usually wait 2 hours, but I may be erring on the side of caution.
https://answers.yahoo.com/question/index?qid=20080325173746AAtUCrv
Dear Pete, Good point! Let’s define “large meal” as a meal containing more than 600 calories with several ounces of protein or meat, carbohydrates, vegetables, and dessert—a typical dinner or large lunch. If you have a meal like this, you should wait three to four hours before running.
http://www.runnersworldonline.com.au/long-wait-run-eating/
I'd say if you are practicing, wait 2-3 hours before running to the point where you are on the verge of feeling hungry again. For a meet I eat 3-4 hours before. People are different in their metabolism, however, so see what works best for your body by experimenting.
https://answers.yahoo.com/question/index?qid=20080325173746AAtUCrv
how long to wait before running after eating
There are three to four hours to wait before running after eating. Wait at least for three to four hours before running after eating.