October 2009 Nutrition Chat with Coach Marni Rakes

author : mrakes1
comments : 0

This discussion focuses on gastrointestinal (GI) upset on the bike and run and several ways to alleviate the issue.

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[Gregkl]   Here is a question that seems to be a source of contradiction. My sweat rate is around 28 oz. per hour. Some say I should therefore drink 28 oz per hour when training/racing. If I do that, I start sloshing like a washing machine. Is there a percentage of fluid loss that I should aim for or should I consume as much as I can and stop short of that full feeling when you drink too much?

[mrakes1]   The issue with hydration is that you can’t replace everything you lose through sweating. The biggest concern is making sure that you are getting electrolytes and calories for the longer training sessions, which you are more likely to sweat more than normal. 

I would focus less on sugary drinks (fructose, glucose) and more from slower digesting carbs (maltodextrin). This will allow you to get in the right concentration of electrolytes and calories without having to overdrink or causing yourself to overconcentrate your drinks, which can cause excess sweating.

I would aim for 20-24 ounces of fluid per hour with 220-240 calories per hour for workouts lasting more than 2 hours. If you need to go with 24-28 ounces per hour, that is fine but I’d try to stay around 24 ounces and go for a drink like Hammer as opposed to Gatorade or Powerade.

[Gregkl]   I have switched to a product, Infinit, that uses a blend of sugars and it worked in my HIM and in my long training rides.

[mrakes1]   As long as you are putting in maltodextrin as the primary ingredient, that should be fine. Avoid a lot of sugars in a drink and amino acids would be good to add in that drink as well. Again, 220-240 calories per hour for 2+ workouts and 150-180 calories for 1-2 hour workouts.

I think 24 ounces per hour (1 sport bottle) would be just fine for you and by avoiding the simple sugars, you will not experience the sloshing stomach. Also, try to drink every 15-20 minutes around 4-5 ounces.

[Gregkl]   Going to volunteer at IMWI this year and probably sign up for 2010 while I am there.  I am thinking I will take 3 bottles of Infinit on the bike and 3 more in special needs for 6 bottles for a 6 hour ride, plus water. I am not too crazy about mixing the concentrate bottles though I am sure that it works.

[mrakes1]   I wouldn’t go more than 280 calories per bottle which is good for an hour for a 6 hour ride. You can grab water at the aid stations, which helps if you do decide to make a 2 hour bottle. I think your plan sounds good. My advice is to grab water bottles at the aid station before the special needs and bring powder of your Infinit. This way you have cold water and you can just mix your powder in the bottles. Plan to bring 4 bags of powder in case one spills.

[Gregkl]   That is a good idea! Never thought of that. That is what I will do. Okay, I got something good out of tonight.

[rachaeld20]   I am having GI problems whenever I run or bike over 3 hrs....I’m not sure what I am doing wrong?

[mrakes1]   It could be from several things just on the top of my head. Pre training nutrition could be a possibility however, I have a feeling it is what you are taking during the run/ride. What do you consume? I’ll try to help with the informal info that you can give me.

[rachaeld20]   Pre meal...it's 2-3 hrs beforehand, no fiber, dairy, refined sugar or artificial stuff.  I experienced major GI issues whenever I run over 10 miles but never on the bike. My last two long rides (50 plus miles) I experienced the same GI problems I do when I’m running long distances. I changed my diet (i.e. 2-3 hrs before I start, low fiber, no dairy, no refined sugar or artificial sweetener).  I am a newbie to the triathlons...my problem is getting in enough to sustain me....I have a tendency to lose weight too quickly and that has caused me problems...should I be eating 30g of protein and 30g of carbs per meal??

[rachaeld20]  During the run/ride...I have tried everything from GU, sparkies, honey, pretzels, power energy/electrolyte drinks.. and it all makes me stop in pain...or slow down a lot.

[mrakes1]   It sounds like it probably won’t be from pre training so possibly GI issues could be from too much sugar during a run, improper timing (too much calories or fluids at one time).

[rachaeld20]  I take everything in with a swallow of H2O...to help it digest faster.

[mrakes1]   I wouldn’t focus so much on grams of protein and carbs. I would focus on around 450-500 calories per your 3 meals and (3-5) 150-200 calorie snacks during the day. I would aim for complete meals of carbs, protein and healthy snacks. Adding in 100-200 calories for every hour of training, over your daily caloric needs will help you from dropping weight.

[mrakes1]   I would focus on a diet of around 55-60% carbs, 20-30% protein and 15-20% fat for your daily caloric needs.  Have you tried maltodextrin products such as Hammer?  I think a slower digesting carb will help you keep your blood sugar stable and provide you with a steady stream of calories. I would aim for around 20-24 ounces of fluid per hour (drinking every 15-20 min, around 4-6 ounces) and not overconcentrating or diluting your drinks.

I suggest the Hammer Heed, 1 scoop mixed in a bottle of 20-24 ounces fluid. If gels are ok for you, I would take your first one after 75-90 min of your run to give your body time to settle in a rhythm. Unfortunately, it’s hard for me to really suggest anything more because I don’t know your daily diet and training routine. Perhaps a nutrition consultation on the BT site would be useful if you need more help on specific training nutrition.

[mrakes1]   Do you experience GI problems with NO nutrition during runs over 60 min? Say, if you were running 90 min and only had water, would you experience these same GI problems as in a 10 mile run?

[rachaeld20]   No, I still have problems when I run for 2.5 hrs without any foods...only water, but that was also in the heat of the day...which also could have been the problem.

[mrakes1]  Rachael, do you run these long runs at an intensity higher than 85% max HR?

[rachaeld20]  Well....I think my HR is higher normally..b/c my HR is always above 160...even if I am not trying hard....I only try really hard during tempo and speed workouts around the track.

[mrakes1]   A lot of nutrition problems happen when the blood is pumping hard to sustain a high HR and thus, it is hard for anything (even water) to be absorbed properly. I say water because too much water at one time can cause GI upset.  That is good that you do the speed work on the track. That will help you for the long runs.

[mrakes1]   Are you able to fully go the bathroom before your runs (#2)?  Also-have you tried to run 90 minutes on an empty stomach? If so, do you still have GI problems? (I wouldn’t suggest more than 90 min of running on an empty stomach but I am fine with 90 min or less on an empty stomach).

[rachaeld20]   Sometimes...if I drink tea of coffee before hand...have my bowels get-a movin’ than yes.  If not....I will be stopping 90 mins into my workout.   I run twice a week for 90 mins on an empty stomach...because its before school and I don't want to feel sick all day...is that bad?...I am sooo hungry post run!  I can bike 2 hours without anything and I am fine energy-wise...

[mrakes1]   I think 90 min on an empty stomach is fine (I suggest a sport drink or water at the minimum with the run) however, if you are super hungry afterwards it would be best to have something small before the workout. I find that even a tsp of peanut butter or a few nuts will prevent overeating (starving feeling) after the workout. Biking on an empty stomach is fine as well. I’m a proponent of empty stomach workouts so long as you properly refuel (ex. protein post workout such as whey, milk or yogurt).

[rachaeld20]   I am thinking correctly that if the more endurance based workout I do on an empty stomach....will I train my body to use stored fat more efficiently?  This way I save my glycogen for when I really need it...like during a race...?

[mrakes1]   Yes, glad you mentioned endurance based because it is really important to keep that HR around 65-75/80% for those longer workouts. However, if a workout is over 2 hours it is best to have a pre training snack around 150-200 calories (ex. for a 2-3 hr workout) so that you don’t finish the workout starving. It is always important to have calories and fluid during workouts lasting more than 90 min/2 hours in order to keep your energy levels stable. Correct, the fat metabolism early in a workout will help with glycogen storage.

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date: November 29, 2009


Master of Science degree in Exercise Physiology. I am a certified sports nutritionist through the International Society of Sports Nutrition,I teach spinning and I am CPR certified. I have finished the 2006 Boston marathon, 2006 IMFL, 2007 Ironman world Championship and I am qualified for the 2007 Ironman 70.3 World Championship. I write for Triathlete magazine and I love writing for BT.com!


Master of Science degree in Exercise Physiology. I am a certified sports nutritionist through the International Society of Sports Nutrition,I teach spinning and I am CPR certified. I have finished the 2006 Boston marathon, 2006 IMFL, 2007 Ironman world Championship and I am qualified for the 2007 Ironman 70.3 World Championship. I write for Triathlete magazine and I love writing for BT.com!

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