Fueling Dreams

As I was struggling to push my swim times up in the cold of last winter (SF Bay drops down to the upper 40’s lower 50’s, with a considerable chunk of time around 52F) I was reminded once more of the importance of feeding and nutrition. This is something I talked about to some extent in my previous posts (see for example here), but I haven’t examined in depth yet.

In this post I’ll do some calories accounting and discuss my personal feeding strategies, in the hope of making some sense and providing some resource for people trying to figure out their own. As always with marathon swimming, feeding strategies depend on many variables and have to be adapted to each person’s characteristics.

Running out of Energy

Bonking, crashing, hitting the wall, … There are many names for the Beast.

The feeling of running out of energy is very well described by the progression in this article: a mental and physical rollercoaster with no brakes.

In marathon swimming you start feeling cold, your arms ache and you feel overly tired. The first time it happens you just blame acclimation or training. Since you usually don’t feel hungry you don’t think that nutrition is the problem. This makes it important to be methodical with your feeds since if/when you feel hungry is probably already too late, so you have to stick to your feeding plan almost religiously.

The reason I’m writing this post is (partially) to rationalize my own feeding plan and to give others some insight on my personal way to do it (which, as always, involves numbers).

The (Nutritious) Facts

Let’s look at some numbers.

According to USDA:

• 1 gram of Carbohydrates contains 4 calories
• 1 gram of Proteins contains 4 calories
• 1 gram of Fats contains 6 calories

Feeding Options

The most popular options (at least in my circle) are:

• Hammer Perpetuem: high calories, you can mix it with warm water, tastes like a chocolate milk hug: 2 scoops (69g) contain 4g fat, 52g Carbohydrates and 7g Proteins for a total of 260 Calories
• Carbo Pro: literally the bread and butter of Marathon Swimmers. I always add 3 scoops of this to my water bottles during a swim. 2 scoops contain 50g of Carbohydrates for a total of 200 Calories.
• Gels: They average around 100 Calories.

I use 20oz bottles which last me approximately 2 hours (4 feeds) each. For each bottle I use 3 scoops (sometimes 4 scoops for Carbo Pro) of powder.

This implies that a bottle contains:

• 390 calories if Perpetuem
• 300 calories if Carbo-Pro

With this assumption here’s how many calories I ingest hourly with some of my most common feeding schedules.

Option 1

• Odd feeds: Perpetuem
• Even feeds: Carbo-Pro + Gel

272 calories per hour

Option 2:

the workhorse

• Carbo-Pro + Gel @ every feed

250 calories per hour

Option 3:

my new go-to

Perpetuem + Gel @ Every feed

345 calories per hour

Burn Baby Burn

The second term of the equation is how many calories are burned per hour while swimming.

This article reports the following figures (depending on the swimmer’s weight):

• A 130-pound person swimming freestyle for one hour will burn 590 calories swimming fast, and 413 calories swimming slower.
• A 155-pound person swimming freestyle for one hour will burn 704 calories swimming fast, and 493 calories swimming slower.
• A 180-pound person swimming freestyle for one hour will burn 817 calories swimming fast, and 572 calories swimming slower.
• A 205-pound person swimming freestyle for one hour will burn 931 calories swimming fast, and 651 calories swimming slower.

I’m around 180 pounds (i.e. 80kg, 10kg more than when I started my journey in marathon swimming!), considering that, while I may not be swimming at high intensity all the time, cold water makes me burn more than I would in the pool, taking the numbers at face value I should be burning around 650/700 calories per hour.

This means that I’m around 200/300 calories short each hour!

This amounts to a whopping 1,500/1,800 calories over a 6 hours swim, so how is this sustainable? Well, the hidden variable here is Breakfast!

I usually eat 2–3 tamales before a swim, washed down with a bottle of Carbo-Pro. According to google a Tamale is around 250 calories (depending on the content).

This means my calorie deficit is down to something around 800 (depending on the number of tamales, the intensity of the swim, etc.).

This is still a lot of calories that have to be replenished right after and/or balanced off by burning fat.

Other Voices

Burning fat in particular is an important source of energy. Other very experienced swimmers (i.e. the awesome Mr. Utsumi and the wise Mr. Simonelli) I train with have told me that they rely more on hydration and feed way less frequently than me. I have noticed myself that feeding on a lot of gels/ingesting lot of sugars makes me bloated and I can hardly keep that regime for more than 4 hours without having a few lighter feeds. By that point I also feel like my engine is well lit up by the initial feeds and it’s sustaining itself burning fats.

On one hand I completely understand their approach to feeding, on the other I haven’t got that to work for me yet.

More Questions

There are so many open questions that I still have to figure out. The point I made above about feeling bloated when overfeeding has to do with how many calories my body can process every hour (300?), and it’s a hidden bottleneck in the equation I explored in this post.

The effects of hydration and the quantity of fluids to be replenished is also another important piece, even though I feel it’s never been a huge problem considering that I drink quite regularly.

Caffeine is surely an interesting twist: how much does it help? how much does it dehydrate me?

I am not a trained nutritionist by any means, and I am extremely grateful to Lauren “tough as nail” Au for helping me navigate this complicated subject and for being a great training partner.

As I said this post is mostly a rambling of napkin math for my own understanding, so take it with a grain of salt.