Marathon Swimming Nutrition: Art vs. Science

First, a Michael Pollan-inspired minimalist manifesto:

  1. Drink some carbs.
  2. Not too much.
  3. Some carbs are better than others.

One of the most daunting and mysterious aspects of preparing for a marathon swim is planning a nutrition strategy. And for good reason: Nutrition can make or break a marathon swim.

So, aspiring marathon swimmers often seek advice from their more experienced brethren. But how to sort through conflicting information and opinions?

  • Lynne Cox munches on bagels with peanut butter
  • David Barra spikes his drinks with ginger tea and agave nectar
  • Erica Rose chews dried pineapple slices
  • Capt. Matthew Webb favored (I mean, favoured) beef tea and brandy
  • For Janet Harris, variety is the spice of life.
  • Peter Attia has been pounding the table for SuperStarch.
  • Penny Palfrey likes watered-down porridge, and famously once had a tub of chocolate ice cream flown in via helicopter (while playing ‘Stairway to Heaven’ in her head!)

The textbooks aren’t much better:

  • In Dover Solo, Marcia Cleveland recommends “warm, energy-providing liquids, followed possibly by some solid food, or energy gel.”
  • Steven Munatones’ book suggests to “try everything within reason: energy drinks, bananas, sliced peaches, chocolate, and cookies.” He also wisely notes that “what works for another swimmer may not necessarily work for you.”
  • Penny Lee Dean devotes a section to nutrition in her book, but in 2012 her recommendations are a bit dated. A lot has changed in sports nutrition since 1998.

Here’s the thing: In planning your nutrition strategy, you must distinguish the art from the science – the “best practices” from the “special sauce.” Think for yourself. Pay attention to best practices, but don’t eat bagels and peanut butter just because Lynne Cox did.

What are the best practices? Here’s a good start:

Drink some carbs. Your gut processes liquid food faster than solid food.

Not too much. The goal isn’t to replace everything you burn. There’s a limit to how much your body can process at once. A basic hour’s portion of Maxim (or equivalent) provides 58g of carbohydrates, 233 calories, and 750ml fluids (a 7.7% solution). Exceed that only with caution and care.

Some carbs are better than others. Maltodextrin is better than simple sugars* (e.g., sucrose, dextrose, and high-fructose corn syrup). Maltodextrin is the typical carbohydrate source in high-end, “designer” endurance fuels such as products by Hammer, First Endurance, and Infinit (and of course, Maxim and Carbo-Pro).

Simple sugars are the typical carbohydrate source in lower-end, mass-production sports drinks such as Gatorade, Powerade, and Vitamin Water.

Basically, if you can buy it at a gas station, don’t use it on a marathon swim.

And… that’s it. All the other stuff – protein, amino acids, electrolytes – you don’t actually need them (and in some cases you don’t want them). Under certain circumstances, they may help at the margin; but there are risks. Supplemental protein and electrolytes have probably harmed more marathon swims than they have helped. The main thing is to consume carbohydrates – in a form and amount your body can easily digest while swimming. Everything else is just “special sauce.”

Regarding the last point: Why is maltodextrin better than simple sugars? To answer this question, I’ve recruited a special guest author. Stay tuned for the next post…

* Note: I am aware of Peter Attia’s argument that SuperStarch is superior to maltodextrin. That may be true – but I haven’t tried it. I would simply note that Dr. Attia agrees that maltodextrin is superior to simple sugars.

30 thoughts on “Marathon Swimming Nutrition: Art vs. Science”

  1. Great post, and timely for me. I’m just starting to work on planning my nutrition strategy. I picked up my first vat of Carbo Pro yesterday. (And lol on “favoured”)

    1. Carbo-Pro is a good product, albeit expensive for what it is. I’m still not convinced there’s any added value over bulk maltodextrin. Will you mix it with anything?

      1. So far, I’ve just mixed it with water and cranberry juice. I should have re-read your post on the subject before shopping–I would have gone for bulk maltodextrin.

        1. That’s what I do, too – though I vary the juices to spice things up. Blueberry, pomegranate, apple, cranberry, grape… pretty much anything except citrus juice.

          The only issue with the bulk malto is it doesn’t dissolve in water as quickly as Maxim or Carbo Pro. I doubt very much there is any performance difference – and I use the bulk stuff for workouts.

  2. I’ll have to read these nutrition articles more carefully. I do remember Swimsuit Addict’s generous and joyful experimentation with yummy things to consume.

  3. Thanks for the link…
    I am no longer using EFS as my primary feed. It has proven difficult to control the electrolyte levels. I have grown to love Hammer’s Perpetuem which I supplement with Endurolyte powder as necessary (more in warm fresh water…. less in cool salt water)

  4. My only long solo swim was 12.5 miles around Key West last summer. Because of the heat, I drank a lot. The Maxim worked well for me. I mixed one and a half scoops of Maxim in 20 ounce bottles and filled them with 3/4water and 1/4 G2 Gatorade. I just like the taste of the Gatorade so it was very refreshing and allowed me to drink a good amount.

    Do you think this will work for the 24 mile Tampa Bay swim?

    1. 1.5 scoops Maxim gets you 116.5 kcal (via maltodextrin). G2 is the half-calorie Gatorade, right? 5oz of that would get you another 12.5 kcal (via HFCS and sucrose). The missing variable here is how often you drink one of those 20oz bottles.

      My approach would be to first decide on the number of calories you want to take in per hour, then adjust the concentration of your drink according to the expected water temp. You probably won’t need to drink as much for Tampa as for Key West (in terms of fluids), but to keep calories constant you’d have to make a more concentrated drink. For Tampa, I drank 30oz per hour.

  5. I think a lifetime of candy abuse has led me to largely feed on Gatorade and sweeter tasting GU products… I need to experiment with some new stuff, but some things I’ve already tried like Perpetuem I can’t even swallow… I’m a picky eater. My low end tastes have done ok for me up to 8 hours… TBD if they’d keep working towards and beyond 12

    1. That’s another reason I didn’t mention that I prefer maltodextrin – the neutral taste. I find Gatorade & GU far too sweet and it nauseates me after a while. With malto, you have complete control over the flavor. Some add Gatorade; I add fruit juice.

      Some people find Perpetuem off-putting, and I think it’s because of the soy protein. Other possibilities you might try include Hammer HEED (which you might find too mild), Cytomax, Infinit, and EFS (but I think the electrolyte content is too high for ocean swimming; Barra agrees).

      When you fed on GU/gatorade, did you take it full-strength? Do you remember about how many calories per hour? Just curious…

      1. With the GU and Gatorade I took it all full strength, I don’t like the taste of either when watered down. No idea on the calories ingested however. I’m decidedly unscientific nutritionally… I do what feels right at the time… possibly an incredibly dumb thing to do, but it’s sort of how I run my life 🙂

        The main thing I’ve learned about myself at this point in my swimming career is if it tastes bad I can’t do it, if it’s bad enough I’ll puke it back up while swimming… and if I puke too much I gas out, so I gotta stick with what tastes good. I hope to someday have the kind of stomach Gords has where he can chow down on a Swiss Cake Roll in the middle of a 20 mile swim 🙂

        1. I read a story about Abou Heif (some would say, the greatest-ever marathon swimmer) that said he chowed down on a hamburger & french fries in the middle of one of his swims. Whatever it takes, I guess!

  6. Thanks for this, Evan – I love the persuasive simplicity of it. But the sociologist in me balks slightly at the “special sauce” side of things. Perhaps this is the difference between food and nutrition, but one of the common features of the interviews I’ve conducted (and of food sociology more generally) is that food performs more functions than simply powering an engine. People have attachments to particular foods for all kinds of nostalgic / habitual / comfort reasons that can help during a long swim – things like longing for a cup of tea (a Brit, not surprisingly), for example. I think this is especially true for those of us who are not so speedy and are in for the long haul. I agree that a core nutritional strategy of liquid carbs makes absolute sense, but I wouldn’t want to write off the ‘special sauce’ side of things so quickly – you don’t have to think those quirky preferences have magical properties to find them an essential part of a nutritional strategy.

    1. What a valuable comment, thanks Karen! This may have gotten lost in the rhetoric, but I didn’t mean to write off the “special sauce”! I think everyone should have their special sauce… my point was merely that it isn’t necessarily generalizable. The “art” of nutrition one has to figure out for oneself. Personally, I have a weakness for Chicken McNuggets (so very American, I know…)

      1. Chicken McNuggets?!! Hilarious. For me, it’s jelly babies. Actually, I’ve just been signed up to be the “fun” evening speaker at the British Sociological Association Food Study Group conference this summer. My lecture title is: “Dreaming of jelly babies: English Channel swimming and the challenges and comforts of food”.

        I like the distinction between broadly generalisable and non-generalisable recommendations though.

        1. It will always be one of my favorite experiences in OWS, hearing Stephanie say at the crack of dawn in Noblesville: “Um, I think Sully’s here. I saw a guy with a shaved head eating a pop tart.”

  7. While on the subject – what do you drink (if anything) during a 60-90 minute practice? I would prefer to drink water, but in the past have been tempted by the taste of Gatorade or Powerade.

    1. Check out my post on “DIY nutrition,” to be published tomorrow (Monday) morning. I use my typical malto+fruit juice drink, but diluted by at least 50%. However, lately I’ve been experimenting with water-only on workouts less than 2 hours. I think Peter Attia is right that the key to fueling a marathon swim is training your body to readily burn FAT. The idea is to “train low, race high” – in terms of calorie consumption.

      1. During a normal practice swim, plain water tastes like “not at all what my body is asking for”. Mixing in a little fruit juice makes a big difference (satisfied feeling during the swim, less fatigue after). It’s an 8:1 water to juice ratio, so I’m hardly adding any calories. I must be craving the electrolytes.

        Evan, when you do a 2-hour swim without “eating” anything, do you take a gel before you get in? I have major problems with fatigue later in the day if I don’t eat something right before I start.

        1. When you mix water and juice, you’re not really getting many electrolytes, are you? Perhaps a little potassium. I think you’re probably craving the sugar in the juice, not electrolytes…? Which is normal.

          I rarely train on a fully empty stomach. For a morning workout, I usually eat something light (e.g., small bowl of yogurt & granola) before I leave the house, along with a swig of juice and if I have time, a cup of coffee. For workouts later in the day, I try to time my meals so I’m neither full nor hungry when I start. If, for whatever reason, I can feel my energy flagging before a workout, a gel can be helpful. For me, being dehydrated is a more common mistake than being hungry.

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