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Eat Smart: Common Nutrition Mistakes for Triathletes


Spring race season is around the corner, so it’s time to start planning not only your training, but also your nutrition. What you put in your body is just as important as your base miles, high-tech clothing and gear.  Failure to address the fourth discipline effectively has sidelined many triathletes and kept them from reaching their race goals.  While some would say these are newbie mistakes, it’s not uncommon to see a seasoned pro fall victim to these avoidable mishaps.   Here are a few common nutrition issues, along with some simple solutions.


Many of us have experienced the performance side effects of dehydration, ranging from small declines in performance to hospitalization and IV therapy.  The good news is dehydration is preventable.  Here are some simple ways to avoid dehydration:

  • Develop a hydration strategy to ensure you consume approximately the same amount of fluid you typically sweat.
  • Adjust your hydration strategies as required; re-test your sweat rate in various conditions and intensities.
  • Frequently test your pre and post exercise body mass to ensure you aren’t losing more than two per cent of your body weight.  If so, increase your fluid intake.  If you are gaining weight, then reduce your fluid intake.
  • For races, make sure you know how often the water stations are, and determine whether you’ll carry your own fluid or rely on aid stations.  If you are relying on aid stations, make sure you plan how much you’ll need for each station.
  • Determine the brand of fluid being offered at the aid station and try it in training.  Races mix the sport drink according to directions on the package, so make sure you do the same.

Insufficient electrolyte intake

Many athletes have suffered the side effects of neglecting to consume electrolytes during training and racing.  The most common side effect is muscle cramping, but electrolyte replacement is important for many other physiological processes during endurance events.  Although the cause of muscle cramping is not well documented in research, those who sweat heavily and are salty sweaters (for example, those who find white streaks on their dark clothing) seem to be more susceptible to cramping.  If you fall into this category, you should consider experimenting with increased electrolytes in your sports fuels.  The electrolyte with the most research supporting its need for replacement during activity is sodium.  Average sport drinks have approximately 400 to 500 mg per litre and most gels contain 50 to 60 mg, but you can find both drinks and gels with double this amount.  Human sweat can have anywhere from 300 to 3,600 mg of sodium per litre.  If you’d like to know exactly how much salt is in your sweat, you may wish to seek testing from a lab (www.medioncorp.com).

If your favourite drink, food or gel doesn’t contain very much sodium, you can supplement with electrolyte tablets.

ThinkstockPhotos-164385148 (1)Eating too much fat, protein or fibre during pre-race meals

While healthy fats and protein-rich foods are important for overall dietary balance, they have a time and a place in the triathlete’s diet. That time is not right before a training session or race.  Fat and protein are both slower to digest than carbohydrates, making them a poor choice for meals eaten within two hours prior to training.  While the small amount of protein and fat contained in peanut butter on your toast or milk on your cereal isn’t likely to cause a problem, a heavy breakfast of eggs, bacon and home fries most likely will.  Pre-training meals should be carbohydrate-based, aiming for at least 60 g of carbohydrates.

Fibre is a healthy nutrient that many people don’t get enough of in their day to day diets.  Although we should be eating high fibre foods most of the time, eating them right before training can lead to bloating, gas and even diarrhea in some athletes.  While the amount of fibre in a few slices of whole-grain bread or a bowl of oatmeal is okay for most, large quantities of fibre found in bran cereals and foods with added fibre should be limited prior to exercise.  Be sure to consume these nutritious foods at other times during the day to make sure fibre intake is sufficient for health and digestion.

Consuming too much solid food during races

During longer races and training sessions that are greater than four hours in length, many athletes experience cherrychia_energygel-1024x680hunger and want to eat solid foods.  While eating solid foods may work during lower intensity training, these same foods consumed during higher race intensity may be difficult to digest.  All too often I have heard stories of athletes consuming sandwiches and bars in T2 and paying for it soon after they start running.  Keep in mind that sufficient calories and carbohydrates can be obtained by drinks and gels, both of which place minimal stress on the GI system.  Using only liquids or gels is a good option for athletes who race at high intensities or those have suffered activity induced gastro-intestinal problem in the past.  For athletes who find they need solid foods, the timing of consumption is important.  Food digestion is most difficult during a run, so aim to eat solid foods in the first two thirds of the bike course.  The best food options are carbohydrate-based foods such as energy bars, baked potatoes, jam or honey sandwiches and fig bars.  Nibble these over a few kilometers to avoid shocking the gut with a huge mass of food.

Not practicing nutrition and hydration strategies before race day

We’ve all done this silly mistake once or twice in our racing career.  Start thinking about your race nutrition early on in the season to practice and refine a plan and a back-up plan.  Try it out at a few less important races so you have it perfected for your A race.  This will avoid any rookie mistakes and keep race-day stress free.

If you need help planning your nutrition, consult a sports dietitian with experience in triathlon.

Alexis Williams is a Registered Dietitian and Personal Trainer in Burlington Ontario.  She is an avid athlete, recently completing Ironman Louisville.  Visit her website www.transitionhealth.ca to contact Alexis for online, telephone-based or in-person nutrition coaching services.