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by Elaine K Howley

July 9, 2014

Best practices for fueling long open water swims

The long-held belief that it’s unsafe for anyone to swim within 30 minutes of eating is just plain incorrect. Marathon swimmers eat while treading water, gulping their food down and heading off towards the far shore in as few as 5 seconds, usually with little problem digesting and no threat of drowning. So much for that old wives’ tale!

Rather than fearing eating, marathon swimmers must take in nutrition and fluids during an event if they hope to maintain an even output of energy over the course of the swim. Because of the vast amounts of energy expended during a swim, long-distance swimmers will always be functioning at a deficit; it’s simply not possible for the human body to process enough calories per hour to replace all that is being used up. But with the internal reserves we all have and a little practice, along with a smart nutrition plan, the negative impact of that deficit can be reduced and swimmers can achieve some amazing things over very long distances.

Nutrition on a long swim is a highly personal thing, and no one solution works for all swimmers across all events. Some swimmers can’t handle solids, as asking the stomach to digest anything denser than a carbohydrate-replacement drink can demand too much effort from an already overloaded system. Other swimmers swear by solids and need to feel a little something in their bellies over the hours they are in the water to stave off distracting hunger pangs.

Whatever you choose to ingest is fine, so long as you’ve tested it before the big day and know that it will agree with your system. Common food and supplement choices among marathon swimmers include:

  • Bananas. Soft, easy to swallow, and packed with complex carbohydrates and potassium, bananas are one of the go-to foods of open water swimming.
  • Clif Bars, PowerBars, or Granola Bars. Though chewy, some swimmers swear by the nutrition found in Clif Bars, PowerBars, granola bars, and other energy bar food products. Try breaking whole bars into smaller pieces ahead of time and taking one bite-sized morsel at a time.
  • Shot Bloks and energy chews. They taste like candy, add a punch of sugar, electrolytes, and other necessary components, and go down quickly. What’s not to love about these sweets? Maybe not the blood sugar spike they can cause, but in combination with other nutrition, they can be very helpful for some swimmers.
  • Candy and chocolate. Some swimmers just cut to the chase and take on gummy bears, Swedish fish, and other chewy, fruit-flavored candies for quick energy. Others prefer chocolate biscuits, bars, and cookies for the nutritional and emotional boost they can provide.
  • Flattened cola. Again with the quick hit of sugar, flattened Coke is a perennial favorite among swimmers near and far.
  • Canned peaches. Long the savior of many a seasick swimmer, canned peaches packed in syrup provide a sweet, easy to swallow and digest hit of sugar that also coats the tummy to help keep seasickness at bay.
  • Carbohydrate replacement powder dissolved in water. Hammer Perpetuem, Maxim, and CarboPro are all popular choices and these kinds of maltodextrin-based nutritional products are considered staples by most long-distance swimmers.
  • Electrolyte replacement tablets or drinks. Some swimmers use Gatorade, others take in salt tablets, while still others use electrolyte drinks such as Ultima Replenisher. There is some debate as to whether ocean swimmers need electrolyte replacements, with the theory being that when a swimmer is submerged in salt water, his body will absorb what sodium he needs from the water and via the inadvertent, inevitable swallowing of sea water. This assumes that swimmers are ingesting an adequate and balanced blend of electrolytes from the water, but that may not be the case. Experiment and find out what works for you.
  • Yummy stuff. Anything else that suits your fancy, feels good going down, and keeps you headed in the right direction is the right choice. The only way to find out what these foods are is to practice. Mix it up during training swims and note how you feel. This will allow you to find the optimum foods for you


  • Open Water