Marathon Swimming Nutrition: A product comparison

by Evan Morrison. 27 January 2012.

I hope you’ve enjoyed “Nutrition Week” here at Freshwater Swimmer. As you may have noticed, I’ve been vague about recommending specific products. There’s a reason for that: I don’t believe there’s any single best nutrition plan for all people, in all situations. However, I’ve personally tried a number of sports drink products, and will share my thoughts on them.

Beginning with the low-end market… These products include, but are not limited to: Gatorade, Powerade, and Vitamin Water. Some signs you might be buying one of these products:

Vitamin Water

Please note: This isn’t an argument about the “morality” of simple sugars. From an exercise perspective, it all ends up as glucose anyway. The issue is osmolality. Because maltodextrin is a larger molecule, it’s easier to consume more carbs without your stomach treating it like food, flooding with water, and causing gastric distress. This might not matter in an everyday workout, but in an 8+ hour swim, it matters.

It’s also easier to control the flavor of a maltodextrin-based drink. By itself, it’s almost tasteless. If you like a sweet, strong-flavored drink, you can always add fructose, fruit juice, or even Gatorade. With simple sugars, the only way to control the flavor is by watering it down - and thus consuming fewer calories.

Now to the higher-end, designer “endurance fuels,” which typically use maltodextrin as their primary carb source.

Unlike Gatorade and Powerade, the nutrition facts and ingredients lists are usually easy to find. I’ve included an image of each product label, which you can click to enlarge.

I also included a cost estimate for each product. It’s not obvious how to do this, given they’re sold in different-sized containers, and often recommend different serving sizes. So, I decided to calculate a cost-per-carb. The standard serving of maltodextrin is 20g carbs in 250ml (8.45 oz) water - an 8% solution. This is approximately what I drink every 20 minutes during a marathon swim. So, the costs listed below are for each 250ml serving of 20g carbs.

The “numerator” of the cost calculation is the largest-sized container available, purchased from with free shipping and no sales tax. If the product is not available from Amazon, I use the price listed on the product website.

Note: The following is written from the perspective of a marathon swimmer, and may be less relevant to runners, triathletes, etc. As always, YMMV.

Hammer HEED

Hammer Perpetuem


GU Electrolyte Brew

GU Roctane

GU roctane drink
GU roctane drink ingredients

First Endurance EFS

Amino Vital Endurance

Generation UCAN

Generation UCAN

Summary and Recommendations

None of these products is perfect.

And that is why… with the occasional exception of Perpetuem, I don’t use any of these products. In the next (and final) post in this series, I’ll review what I consider to be the two best options for marathon swimmers:

  1. Purchase a plain (unflavored) complex carbohydrate, such as Carbo-Pro, Maxim, or Generation UCAN-plain, and flavor it yourself.
  2. Infinit Nutrition.

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