How to nail nutrition for swimmers by marathon swimmer Sarah Thomas

When you’re taking on a long swim that requires feeds, dialling in your nutrition is paramount to success. You can fake it for shorter swims, but once you start getting into 12-hour+ swims, there is less room for error. Marathon Swimmer Sarah Thomas has your guide to nutrition for swimmers.

There are four components for a well-balanced swim meal: water, carbohydrates, protein and electrolytes. Start with a baseline and then find what works for you.

1. Record everything you eat leading up to and during long swims. Calories and hydration ahead of time make an impact, so if you miss before you swim, it doesn’t matter how perfect your swim nutrition is. Make note of what you ate and how you felt so you can replicate it later when it’s a success.
2. Try your swim nutrition before the big event to get a sense of what is working… or not.
3. I highly recommend finding a powder mixture that meets all of your needs in one place and consuming mostly liquid feeds. It is easier to drink than chew and you can speed up your feed stops by having one consistent feed in a water bottle throughout.
4. You may need to adjust your feeds depending on water temperature. For example, on hot swims, I tend to lessen the calories and increase the water and electrolytes. For super cold swims, my body responds better to more density.
5. Plan for feeds every 30 minutes. Thirty minutes will keep your blood sugar level. You want to be hungry, but not starving, when it’s time to eat and feel satiated, but not stuffed, when you’re done.

Where to start

• Powders are nice because they can mix all your needs into one bottle. Don’t plan to consume more than 8 ounces of liquids at any one stop. Start with a pure maltodextrin mixture that is straight carbs/calories. From there you can build in your protein and electrolyte needs.
• Most people need around 200 calories per hour during sustained activity with about 50 grams of carbohydrates. Some of you may need more/less, but start here and go up or down depending on how you feel. Feeling bloated? It’s too much. Feeling weak or like you’re losing energy? It’s not enough.
• You want a mix of complex carbs and simple sugars.
• Protein is controversial. Some people find it makes your stomach upset, but some of us crave cheeseburgers!
• Start off without protein. If you’re still feeling hungry, try adding in a small amount of protein to each feed. I’ve used both whey and rice proteins with equal success.
• You will need electrolytes whether you’re swimming in fresh or salt water. Check your contents and make sure your product has a mix of calcium, magnesium, sodium and potassium.
• If you do need solid food options, things to try: rice, oatmeal, baby food, boiled potatoes, canned peaches. Things that are easy to eat and digest are key!

*This advice is based on personal experience; I am not a nutritionist. Please consult a doctor or specialist if you have any special nutrition-based needs. Conduct your own research before starting a new supplement.

Sarah Thomas is an American ultra-marathon swimmer. She holds the world record for longest, second-and third-longest current-neutral swims. She also coaches and supports other marathon swimmers helping them to achieve their swim-dreams.

Read more about nutrition for swimmers.