How much to eat before running?

My son texted me after completing a run and asked me what are the causes of feeling nausea when completing a run? While this is a loaded question (could be heat, running too soon after an illness, or trying to run off a hang-over) we quickly figured out that he had eaten very close to taking off for his run on a hot day.

But this begs a question that we don't see too much written on in running magazines, blogs, and training. How much, when and what kind of food, should one eat before running? For those just getting into running, this is an important question to address when planning a morning, afternoon, or evening run. This is also a question that many experienced runners wonder about when they have a bad performance in a race and they are wondering if when, how much and what they ate affected their performance.

For Marathoner runners this is probably a more important answer than someone running a 5K. But that is because if a Marathoner makes a mistake on food intake, that is a mistake that will either cause those minutes, not seconds in a race or have them drop out altogether.

The best rule of thumb that I've seen is Weight times Wait = Runner's Fate. In other words, you multiple the runners' weight (in lbs.) times the length of time he/she will be running to determine the total calories that can be consumed before a run. So for a 150 lb. runner that is eating 2 hours before a run/race, he/she would consume 300 calories. If their race is in one hour, no more than 150 calories. This works for the 100 lb runner as well as the 250 lb runner.

This has worked for me for years and I've never tossed cookies yet. That's not to say I haven't run a 5K that I almost lost it, but it was from effort, not food, that caused the feeling.

What should you eat? Well, it should be mostly, if not all, carbohydrate. I'm on this 4:1 ratio kick, which has me eating 4 times the grams of carbohydrate for every 1 gram of protein. I firmly believe that fat does nothing for you in preparing for a run or a race. I know, I know, you need to burn fat in a long endurance run or race, but the human body has more than enough fat to supply that need. Carbohydrate is what activates the fat burning machine.

Should it be solid or liquid? Liquid gets absorbed quicker, but if I'm eating 2 hours before a run, my choice is a quickly digestible carbohydrate, like a PowerBar, Clif Bar, Banana, Bagel, etc. Anytime less, than I would go with liquid (Accelerade, Gatorade, Energy Drink) or a soft food, like a Banana.

Remember this, food can hurt your performance when eating too much or too soon, to run/race time. If you haven't practiced this in your weekly runs, eating too many calories too close to your race can affect it.