Experience From - Karl King#1, Karl King#2, George Parrot, Wendy Shuttleworth, Karl King#3, Mark Dorion , Alex Feldman , Karl King#4 , Karl King#5 , Karl King#6 , Rich Schick

Karl King #1

Subject: Pepsi/Mt. Dew, Cramps, Diarrhea

George Beinhorn mentioned cramps, and Ed Furtaw mentioned diarrhea after using these drinks a lot in an ultra. There are three contributing factors in using soda as a sports drink.

  1. whey usually contain either high fructose corn syrup or sucrose as the sugar source. Sucrose is split into glucose and fructose in the digestive tract. Many people get diarrhea from large amounts of fructose. As Ed notes, it tends to pull water into the intestines. That reverses the hydration process and causes diarrhea.

  2. If you take a lot of caffeinated soda, you may over dose on caffeine, particularly if you don't use it much away from the run. Caffeine and other xanthines ( tea, chocolate are sources ) cause relaxation of smooth muscle. Net result: urgency along the way. Combine that with the tendency for diarrhea caused by too much fructose, and you're primed for extra potty breaks.

  3. The electrolyte balance of most sodas is terrible for running. Many have no sodium to speak of. Unless you take in other sources of sodium, you may mess up your electrolyte balance and get cramps. If the fructose and caffeine aggravate water loss, that can only make dehydration and cramping more likely.

Small amounts of these sodas along the way can help, but don't make them your primary source of anything.

Karl King #2

Subject: Calcium Loss

Coke and other soft drinks are acidified with phosphoric acid ( see the list of ingredients on the side of the can/bottle ). When food passes from the stomach to the small intestine, bicarbonate is added ( by the digestive apparatus ) to raise the pH. Under the acid conditions of the stomach, the calcium in food is available, but when the pH goes up in the small intestine, the calcium reacts with the phosphate from the soda and precipitates. In that form, calcium phosphate, it is not available for absorption.

This has nothing to do with the color of the soda.

Drinking lots of soda on a daily basis is not a good idea for many reasons. In addition to calcium interference, sodas provide empty sugar calories - no vitamins, no minerals, no fat, no fiber, no salt.

A can or two once in a while is nothing to worry about, but if you're drinking more than a can per day, you're cheating your body out of nutrients it could get from less refined sources.

It is the contention of some food scientists that some major food suppliers deliberately omit important nutrients from their products so that the under-nourished body will eat more, seeking that which it has not been given. As one man put the question: Who in the audience has eaten just one Oreo?

George Parrot

Subject: Calcium Loss

Yes, phosphoric acid in colas--and many other sodas, is a binder to restrict the access of calcium to the body...

I drink a lot of colas, but now I take calcium supplements....

Wendy Shuttleworth

Subject: Calcium

This thing about Calcium loss from drinking quote "brown & yellow sodas", the only thing I can think is that the Dr. was referring to the caffeine containing sodas (which certainly include colas and Mt. Dew). I know that caffeine effects Ca absorption or something like that and is implicated in osteoporosis, however surely the caffeine content of sodas is a fraction that of coffee. This has always been a dilemma for me... am I benefiting from the non-fat milk in my latte, what if I have a double!

Karl King #3

Subject: Coca Cola and Running

What's in Coca Cola, and how do the ingredients relate to running?


The combination of carbohydrate energy from the sugars, and the caffeine gives a boost in energy which is why colas are popular with some runners. The acidity of the drinks is a drawback. You can get equivalent results by using a sports drink and a caffeine source that is not acidic, such as NoDoz or guarana.

Some runners favor Mountain Dew. It is nutritionally similar to cola but may have additional stimulation from the brominated vegetable oil that is part of the drink's flavoring.

When I started running ultras, a veteran warned me that once you start taking cola, you should do so until the end of the run because if you stop, you can get a major crash in energy.

Mark Dorion

I have conducted "unofficial" tests during local trail runs I put on. Over the last 7 years I have offered coke, mt. dew, sprite, gatorade and various other drinks. Last week's Baylor Peaks Run once again showed the drinks of choice (this is a tough 25 miler all on narrow rocky trails with significant climbs. As I have to backpack all aid in to the self-serve aid stations the day before (both are about a mile from nearest road) it is important to know exactly how much of what to have).

Gatorade/ Powerade goes untouched and I will stop offering it as of the next El paso trail ultra (big Pig 8 hour next week, Piggyback Trail Marathon Jan. 18-- interesting course by the way). Does anyone else find it amusing that Coca-cola Co. spends so much time and money marketing their sports drink Powereade when if they asked ULTRARUNNERS and directors they would realize that regular Coke is greatly preferred??

Besides Coke mt. dew/ surge are popular choices, in fact these latter two are probably used as much as water in some of my runs.

It seems these soft drink companies could get some good spokespeople at most any ultra, plus some dramatic footage of scenic trails, mts., roads to boot.

Alex Feldman

Subject: Diet Coke

I read some papers on aspartame a long time ago, and I don't have references handy. I don't like to state "facts" without references, but I will here, because I'm pretty sure of these:


Aspartame is the most assiduously studied food additive ever developed, by far. If there were anything really wrong with it, it would be established beyond the level of rumor, where it seems to be now. I don't eat much food with aspartame in it, but that's more a matter of lifestyle than concern. It wouldn't bother me at all to ingest it.

Karl King #4

Subject: Soda as a Sportsdrink

Randy Christian asked if sodas are better drinks than "gatorade type" drinks.

So, sodas are not good substitues for sports drinks. They are useful for supplementing sports drinks or "real food" during an ultra, but they should not be used as one's sole source of calories and electrolytes.

Karl King #5

Many runners enjoy cola in an ultra because it provides quickly assimilated carbohydrate calories and caffeine. Some runners favor Mountain Dew which also is a good source of sugar and caffeine, and contains the flavoring brominated vegetable oil, which may act as a stimulant in some people.

Coca Cola also contains phosphoric acid which may provide additional phosphate to assist energy production.

Like most runners, I find that some cola late in an ultra provides an energy boost. As long as I don't take too much at one time, cola doesn't bother my stomach.

Cola is about a 10% solution of sugars, primarily sucrose and/or high fructose corn sweeteners. Individuals vary in their ability to absorb these sugars well. Some could drink the stuff all day, while others would end up with a bad stomach. Some people have a hard time absorbing fructose, resulting in diarrhea or stomach cramps.

The fact that bikers can drink only Coca Cola in a bike ride doesn't necessarily imply that runners should do the same. For one thing, biking events are usually much shorter in duration than ultras. Biking places less stress on the digestive system than does running, so bikers can digest a wider range of carbohydrate sources than runners without distress. For example, I cannot drink Gatorade in a marathon or ultra without serious problems from it, yet I've done 50 mile bike rides where it worked fine.

One drawback of sodas is that they are generally acid. Since we produce acids when we run, our bodies are continually trying to eliminate it from the system. Drinks which are slightly tart taste better than more neutral drinks, but the best energy sources for running are the non-acid ones.

The caffeine in colas and other sodas clearly provides an energy boost. Studies which report controversial results on the effects of caffeine are seldom done on ultra runners. "Endurance" events to most researchers last 20 minutes to an hour, so their studies are not really relevant to someone who has been running for six hours.

The primary muscle fuel is adenosine tri phosphate ( ATP ). As fatigue builds, phosphate is lost for the adenosine molecules. As a protective measure, the adenosine is absorbed on receptors located on cell walls. That means there is less adenosine around to be re-phosphorylated. One way to get that adenosine back in circulation is to provide molecules which bind more tightly to the receptors than does adenosine. One family of molecules which will do that is the xanthines found in coffee, tea and chocolate. The most common xanthine in our diet is caffeine.

So, the caffeine in cola or Mountain Dew gives a runner a lift by making adenosine more available when in a state of fatigue. The sugar in the soda provides the energy for bringing the adenosine back to the useful ATP form.

A similar action is available from Chocolate GU ( or similar product ). The maltodextrin provides the caloric energy, and the chocolate provides the xanthine theobromine to bind to adenosine receptors.

What has worked well for me in my runs is to use the sportsdrink of my choice, and add xanthines in capsule form ( Guarana ) when I feel the need, such as at night or when low on energy. Caffeine is very water soluble so gives a quick boost but a fast fade, so I don't particularly like the NoDoz form. Theobromine, the xanthine in chocolate, is less soluble so is slower to act and also fades more slowly. Guarana, a vegetable source of xanthines, works well for me, and is easy to take in tablet or capsule form. By using that as a source of xanthines, I avoid the phosphoric acid and fructose of Coca Cola.

Guarana is readily available from most health food stores.

As an ethical matter, it should be noted that xanthines are drugs: you can live your entire life without ever using them. As a practical matter, coffee and cola are so available that it is hard to argue that runners drinking cola have some illicit advantage. Caffeine is not a banned substance under USOC rules unless it is taken in very large doses, equivalent to 8 cups of coffee.

Karl King #6

Jay raised some questions about apartame.

It is a di-peptide of apartic acid and phenylalanine. Both of those are very common in foods with any significant protein content.

Phenylalanine is an essential amino acid, so the body can handle it quite easily. Aspartic acid is a very common amino acid.

To imply that Aspartame is 10% methanol is grossly incorrect. If that were true, the compound would cause widespread blindness and nerve damage, and would never have been approved for food use.

Small amounts of methanol are produced in the metabolism of aspartame, but the body can detoxify those amounts. According to the literature, more methanol is produced by the metabolism of a tomato than a can of soda sweetened with aspartame.

I never met a carbohydrate I didn't like, so I rarely have anything with aspartame in it, but when I do, no sleep is lost over the matter.

As far as being a source of calories in a soda, the amounts are so small that it is essentially useless. Diet sodas are just flavored water.

Rich Schick

Subject: More What to Eat (Drink)

Found this tidbit cruising the web,liked it because Coke is my preferred beverage rather than all that "Yuppie gunk"

A thirst only Coke can satisfy?

Assume you're a competitive road cyclist and you've been racing for more than four hours in hot conditions. Your carbohydrate stores are dwindling and your body water has dropped by more than four liters. With less than an hour of riding to go, you enter the feed zone one last time. As you look for every possible advantage, an important question dominates your thoughts: "What should I drink?"

In the sport of road cycling, competition typically occurs on successive days and generally lasts 2 to 6 hours. Competitions can be characterized as aerobically demanding with short high-intensity efforts that involve anaerobic energy systems. This type of activity depletes body water and muscle glycogen, so carbohydrate-electrolyte sport drinks are recommended. At the Australian Institute of Sport, athletes undergo nutritional counseling to ensure that they are aware of drinking strategies that are compatible with current scientific wisdom. But we have noted on many occasions that Aussie road cyclists, mountain cyclists, and cross-country skiers drink Coca-Cola during competition. The consumption of soft drinks, especially colas, was a common practice among athletes 20 years ago (VanHandel, et al., 1977), but you would think that top athletes would now be using the recommended sport drinks. We decided to do a survey during the US Professional Cycling Championships to find out what the best cyclists use.

Details of the Survey

A survey was constructed that would allow soigneurs of professional cycling teams to identify which drinks were consumed by their riders during the 1997 CoreStates US Professional Championship Road Race held in Philadelphia, Pennsylvania. During the race soigneurs were approached in the feed zone and asked whether they would be willing to fill out the questionnaire which was primarily designed to understand which sport drinks were being consumed by professional cyclists during the race. Soigneurs were told that the survey was not sponsored by a sport drink company. The questionnaire involved 12 questions and was generally completed within 5 minutes.

Representatives from 11 of 19 teams professional men's cycling teams completed this survey. Teams varied in number from 5-10 cyclists and most of the teams were composed of cyclists who were from the United States. Cyclists from the following countries were also included on teams that completed the survey: Australia, Belgium, Canada, Czech Republic, France, Great Britain, Germany, Italy, Netherlands, Russia, and Spain.

Most Professional Cyclists Prefer Coca-Cola

In six out of the 11 teams, all of the riders drank Coca-Cola during the race. More than 67% of the riders drank Coca-Cola in four of the teams and only one team was identified that did not drink Coca Cola during the race. Thus, roughly 90% of the teams surveyed consumed Coca-Cola. In all cases Coca-Cola was consumed during the last half to the last quarter of the race and was used as a supplement to some other type of carbohydrate electrolyte drink. In seven out of the 10 teams that used Coca-Cola, the drink was handed out to the riders "de-fizzed." In other words, the Coca-Cola was not fully carbonated at the time of consumption. Coca-Cola was consumed as a post-race drink in conjuction with some other type of carbohydrate electrolyte or protein drink in eight out of the 11 teams surveyed.

Why is Coca-Cola so Popular?

At the US Professional Cycling Championships, Coca-Cola was the preferred "sport drink" for the final stages of the race. Although conventional scientific wisdom might not support this practice, data from our survey documents that consumption of Coca-Cola by professional road cyclists remains pervasive. It is possible the taste, the availability and the caffeine content contribute to the popularity of this drink for endurance athletes. However, it should be noted that thus far researchers have not been able to document that the caffeine content (Perkins and Williams 1975) or that the carbonation associated with Coca-Cola (Zachwieja, et al. 1992) provides an ergogenic effect. Of particular concern is the relatively high carbohydrate content of most cola drinks which may decrease gastric emptying (VanHandel, et al. 1977).

Further research is required to see how much Coca-Cola is used as a sport drink by other top endurance athletes. But more important, any ergogenic effect of Coca-Cola remains to be established. Is it possible that the carbonated water, sugar, color, food acid, and flavors contained in the red and white can is truly superior to all the scientifically designed sport drinks that scientists recommend? Is this another example of athletes being ahead of scientists?


Perkins, R. and Williams, M. (1975). Effect of caffeine upon maximal muscular endurance of females. Medicine and Science in Sports, 7, 221-224.

VanHandel, P., et al. (1977). Physiological response to Cola ingestion. The Research Quarterly, 48(2), 436-444.

Zachwieja, J., et al. (1992). The effects of a carbonated carbohydrate drink on gastric emptying, gastrointestinal distress, and exercise performance. International Journal of Sport Nutrition, 2, 239-250.