The last in a series of four posts about nutrition in marathon swimming. To recap:
- Marathon swimming nutrition is both art and science. There are both “best practices” (generalizable to many) and “special sauce” (generalizable to few). In general, a nutrition plan that aims to drink some carbs — not too much is a good place to start.
- Some carbohydrates are “better” than others, due to differences in osmolality. An endurance athlete can consume more carbohydrate in the form of maltodextrin, compared to simple sugars, without overwhelming the digestive system. Also, maltodextrin is neutral in taste, thus providing more control over your drink’s flavor.
- Of the many designer endurance fuels on the market, few are ideal for marathon swimming. High electrolyte content makes sense for runners, cyclists, and triathletes – but less sense for swimmers (even less sense for ocean swimmers).
Although I do think Perpetuem is a good product for swimmers, my best advice is to **skip the one-size-fits all formulas and do it yourself.**This is the only way to ensure you get the nutrition you need on a marathon swim, and not the stuff you don’t need.
There are two basic varieties of “DIY,” the “full DIY” and the “semi DIY.”
The Full DIY
- Buy some **plain complex carbohydrate**– maltodextrin (Carbo-Pro, Maxim, or bulk) or if you want to be adventurous, Superstarch.
- Mix your chosen carb with water, and **flavor it**with something tasty. Possibilities might include fruit juice or Gatorade.
- Calculate your drink **recipe**by:
- how many calories (including the ones in your flavoring) you want to consume per hour
- how much fluid you want to consume per hour
- If you’ll be swimming in warm water and/or freshwater, add some **electrolytes**(e.g., Hammer Endurolytes). Keep in mind many fruit juices already provide some potassium.
- If you want to add some **amino acids**, go for it (try this).
This is, in fact, exactly what I do. For a 30-oz feed bottle, I mix:
- **1/2 cup maltodextrin**(bulk for everyday use; Carbo-Pro or Maxim for race day)
- **6 oz fruit juice**– anything but citrus. On my big swims last year I used unfiltered apple juice. But other juices work great too – cranberry (unsweetened), blueberry, cherry, pomegranate, grape, etc. You can even blend them!
- **24 oz water**
This recipe provides approximately 280 calories and 70g carbohydrates (depending on the juice). Assuming bulk maltodextrin ($33.54 per 12 lbs) and premium juice ($4 per quart), the total cost of my 30-oz custom bottle comes to $1.06. For everyday workouts, I dilute the recipe by 50%, bringing my cost down to 53 cents.
**Important Caveat:**Some people have trouble digesting fructose. Fruit juice contains fructose (along with glucose & some other stuff).
**Always test your feed plan before you use it on a marathon swim!**
The nutrition info for Maxim and Carbo-Pro are pretty boring, but here they are anyway:
- carb source: maltodextrin only
- extras: Vitamins C and B1
- cost per 250ml: $0.32
- carb source: maltodextrin only
- extras: none
- cost per 250ml: $0.45
The Semi DIY
- Go to the Infinit Nutrition website.
- Complete the online interview (or schedule a phone consultation).
- Get your customized formula. Infinit will blend it, put it in a nice little bag, and mail it to you.
Everything is adjustable – flavor, calories, electrolytes, protein, amino acids, and even caffeine. Tell them what you want, and that’s what you’ll get. You could even have different formulas for different swims – perhaps a low-electrolyte formula for a cold ocean swim, and a medium-electrolyte formula for a warm lake swim.
(No, I’m not getting anything for saying this. However, my buddy Jared – who initially brought Infinit to my attention – is sponsored by them.)