pre marathon nutrition and hydration

[Luz]

I've been reading concerns about how to eat & 'eliminate' properly before race day.  What is carb depletion and carb loading?  Is it important, and if so, how do you carb load before a race, without having 'stomach issues' during the race.  Please advise what is a typical eating plan the week and days before the marathon.  Thanks!

[Josse]

I would advise not to change your diet drastically.  This is what will give you any GI issues.  I have tryed depleating and loading and think it screws with the bowels way to mcuh and can drain your immune system.  I have gotten sick every time I have done it.  Just eat good and maybe alittle more carbs.  Don't over drink either this can depleat your electrolytes and give you more of a problem than under drinking.  Trust me I know.

[AndyBrowning]

I believe the idea of carbo loading is to shift the percentage of your diet to more carbs - you shouldn't eat more, just more carbs.  A very common mistake that people make (myself included) is to pig out for the 3 days leading up to the marathon and call it "carbo loading".

[Luz]

See you guys are assuming I understand what carb loading is and when you should do it.  So far I've got, keep eating healthy and normally, and don't overhydrate.  So maybe carb loading is just as simple as eating spaghetti the day before a race?

[Josse]

In my book it is, and maybe alittle more carbs through the week.  But like Andy said it doesn't mean pig out the week before.  Just keep eating like you normally do plus a few extra carbs.

[James Winzenz]

There are a couple of thoughts behind the idea of carb loading:

1.  Your body can more quickly process carbohydrates than it can fats and proteins.  That is, they are quickly broken down in the stomach, where some simple carbs can be immediately absorbed into the bloodstream, and on into the small intestine, where they continue to be absorbed into the bloodstream and on to the muscles or liver for storage.

2.  It takes the body less energy to convert carbohydrates to ATP, which your body uses for fuel.  Glycogen is kind of a temporary rest stop in the energy burning cycle, and is the form that is used to store the supply of fuel, both in the muscles as well as in the liver.  There are small differences (as I recall) between the structure of muscle glycogen and liver glycogen (which is used to supply the brain with fuel).

3.  In general, it is much easier to digest carbohydrates than proteins or fats.  I have had experiences where I have eaten a fatty meal at 5 PM, and have gone out for a run at 9 PM, only to still feel the food in my stomach and feel yucky.

Your question below takes all the science out of it and makes it nice and simply - yes, the typical approach is simply to eat pasta (and bread) or other complex carbs that will help you to ensure that your muscles have the maximum glycogen supply for the race, since that is the easiest form of fuel for the muscles to use.  Once you run out of your glycogen supply, if you don't replentish with easily digestible carbs (thus gels/blocks and gatorade), your muscles will be forced to utilize other less efficient forms of energy (i.e. converting fat to fuel, which is very energy intensive and slower than the process of converting carbs to fuel).  Long-winded answer for a simple question . . .

[Luz]

I really appreciate the information you guys.  In addition, Josse was kind enough to give me a run down by phone about carb depletion and loading.  Last year I gained about 7 pounds before SGM by following a running guide that suggested resting on the days before a long run and doing low impact cross training the day after--that plus carb loading before long runs & races (which I took to mean eat 3,000 calories in a single sitting...oops). I did run a strong race last year, but I was in constant need of a bathroom!  I'm opting for way more moderation and this time around, with maybe a little pasta on Friday and replenish with Gatorade during the race as James suggested (gu and gel blocks make their way right through me, taking everything else with it).  I did finally Google carb loading and this is what I found from the Mayo Clinic (although I'd still love more comments, personal experience, and suggestions):

    * Step 1. About a week before the event, reduce your carbohydrate intake to about 40 percent to 50 percent of your total calories. Increase protein and fat intake to compensate for the decrease in carbohydrates. Continue training at your normal level. This will help deplete your carbohydrate stores and make room for the loading that comes next.
    * Step 2. Three to four days before the event, increase your carbohydrate intake to 60 percent to 70 percent of your daily calories — or about 4 to 4.5 grams of carbohydrates per pound of body weight. Cut back on foods higher in fat to compensate for the extra carbohydrate-rich foods. Also scale back your training to avoid depleting your glycogen stores. Rest completely for a day or two before the event.

Various studies suggest that simply resting and increasing carbohydrate intake two to three days before a high-endurance activity is effective, too. But there are a few caveats. Carbohydrate loading works best when you've been on a carbohydrate-rich diet throughout your training — and it may be more effective for men, perhaps because endocrine differences between the sexes cause men to utilize carbohydrates to a greater extent during endurance exercise. And even if you've loaded up on carbohydrates ahead of time, you still need to replenish them during the event to maintain your blood sugar levels — especially if you've been going for more than 60 minutes. Try a piece of fruit or a sports drink.

Is this helpful and universal information according to actual runners?

[James Winzenz]

That sounds good, although like Josse, I am not particularly in favor of carb depletion.  I would also agree that needing to have a carbohydrate-rich diet all during training is pretty important.