70.3 Nutrition and Hydration Prep

Reading Time: 5 minutes

Last Updated on September 13, 2024 by Cory Kawa

I’ve had some epic bonks over the years, from my first 70.3 in 2017, when the 1km walk back to my car took almost an hour, to bonking hard in Orilla while riding the Simcoe County Loop Trail. All this has made me realize how important it is to nail your race day nutrition and hydration prep.

From that first bonk to now, I’ve tried many strategies to dial in my nutrition. Some utterly failed, and some have been a bit more successful.

As I prepped for my fifth edition of the Barrelman Niagara Falls Triathlon this weekend, I stumbled across this never-published article from my archives, discovering some great tidbits that I hope will power me to crossing the finish line, depleted but strong on Sunday.

I’ve had some epic bonks over the years. Read on to learn how I went down the rabbit hole and nailed my 70.3 nutrition and hydration plan.

Disclaimer: I am in no way an educated expert on nutrition. This is only meant to summarize what worked for me in 2022 and what I hope will continue to work for me in 2024.

Why I Bonked and My “Facts” on Hydration and Nutrition

I want to reiterate that I’m not an expert on nutrition. The following “facts” represent the basic guiding principles I have followed with an evolving level of success.

I will also note that, in my experience, personal nutrition success requires constant experimentation and tracking of what works and what doesn’t.

As you read through the below, the most important takeaway I can give you is to mimic your race-day nutrition in training and to track everything, including how it makes you feel, helping to formulate a plan uniquely suited to you.

What is Bonking?

Bonking occurs when the body uses up all its available glycogen stores. Dehydration can be an aggravating factor for bonking and can have an equally bad, if not much worse, impact on overall performance.

Bonking Key Concepts:

• ⛽ Glycogen vs Fat Burning – The primary fuel source your body accesses during exercise depends on the level of intensity, with fat being the primary source for lower intensities and carbohydrates being the primary for higher intensities. In the article “The Truth of Fat Burning Zone,” Dr. Ong notes that when operating in the aerobic zone of 81-93% of max heart rate, calories burned will be equally split between fat and glycogen (carbohydrates).
• 🏦 Glycogen – The body’s storage of carbohydrates. Most articles I’ve read state that the body stores a maximum of about 2,000 calories of glycogen, with only 70-90% of that storage being accessible.
• 🔥 Calorie Burn Rate—As a 175-lb athletic male, I typically burn 750-1,000 calories per hour when performing at intensity. Using Dr. Ong’s ratios above would mean I’m burning 375-500 calories of per hour.
• 🍫 Replenishing Carbs – Most articles I’ve come across claim that people can easily replenish about 60 grams, 240 calories, of carbs per hour. With practice and training, some articles claim that some athletes can stomach 90 grams / 360 calories or more per hour.

Hydration Key Concepts:

• 💧 Sweat Rate – Varies wildly between people and highly depends upon conditions, with 1 to 1.5 litres per hour being a safe assumption for most people depending on conditions.
• 🔃 Water Absorption – Hammer Nutrition has a great article about water absorption where they note that most people can only absorb a maximum of about 1 litre of water per hour in hot and humid conditions, suggesting that 500-750ml may be a more optimal target amount.
• 🚰Drinking on Course – A typical aid station cup holds about 120ml of water and, in my experience, is typically only about 1/2 to 3/4 full, meaning we usually take in about 60-90ml of water per cup.
• ☀️Dehydration – According to Sports Cardiology BC, the negative impacts of dehydration start to affect performance when body weight decreases by 2% (3.5lb or 1.6 litres for me), with performance decreases of as much as 30% when weight decreases by 5% (8.75lb or 4 litres for me). This means after just an hour of exercising outside, in full sun, without replacing fluids, I can expect significant performance declines, and after two hours, I can expect near-critical declines.

My 70.3 Nutrition and Hydration Strategy

After bonking hard in 2017 and following that up with a couple of lacklustre performances in 2018 and 2019, I decided to focus on nailing my nutrition and hydration in 2022.

My 70.3 Hydration Plan

The first part was to understand my sweat rate over various distances and conditions. Precision Hydration has a great calculator that makes this very easy. Depending on activity level and conditions, I vary between 1 and 1.6 litres per hour.

My goal is no longer to drink to thirst but to, instead:

• 🌃Pre-Race – Drink a low-sugar electrolyte drink the day before to help boost my electrolyte levels.
• 🏊Swim – Drink half a bottle of my preferred electrolyte drink about an hour before the swim and the other half when finished.
• 🚵Biking – Drink at least one 750ml bottle an hour, depending upon conditions, with sips every 8-12 minutes to maximize absorption.
• 🏃Run – Understand the intervals for on-course drink stations. Assuming that each aid station cup holds an average of 80-120ml of fluid and that I need to aim to replace about 750 of fluid, I’ll need to ensure that I’m drinking anywhere from 6-9 cups per hour depending on the weather and the fullness of each cup.

I will also try to only drink things infused with electrolytes whenever possible.

My 70.3 Nutrition Plan

I’ve now worked myself to where I can comfortably target about 60 grams of carbs / 240 calories per hour. Any more than that, and I begin to experience gut rot.

I’ve also found that taking half my calories through fluids and the other half through gels works best.

During 70.3 events and training, I used F2C Glycodurance as F2C is the on-course nutrition at all the events I’ve participated in. My preferred ratio of Glycodurance is 5 scoops (500 calories) per 3 bike bottles. To maximize palatability, I’ll make this at a ratio of half-flavoured and half-not-flavoured.

To get to 240 calories, I do the following:

Mimic 70.3 Race Day Nutrition / Hydration in Training

The old saying is to not do anything different on race day that you are not already doing in training, and this should definitely apply to nutrition.

With that, my current race day drink of choice is F2C, not just because I like the taste and it seems to work well for me, but most importantly because they are the on-course nutrition provider at MultiSport Canada events.

If that were ever to change, I would probably look to change brands to ensure I’m taking a brand I’m familiar with come race day.

Adjusting for an Olympic Distance

In 2022, when competing in an Olympic event, I kept the same plan in place, with a couple of minor modifications:

• 💦Hydration – I aim for similar hydration levels the night before, before the swim, on the bike and on the run.
• 🍌Nutrition – Reduce the calories I consume by more than half, using F2C Hydradurance instead, consisting of only 10 grams of carbs per scoop, 16 grams per bottle, and one gel per hour.

Final Thoughts

This plan worked well for me in 2022. As I head into my fifth edition of the Barrelman 70.3, I hope to replicate my success in 2022 and will report back shortly on what did and didn’t work.

Thanks for reading,

Cory

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