Race-week nutrition strategy
Camino's own in house nutritionist Loren Turnbull of Elite Fit Food shares her knowledge to help you prepare for Ironman Cairns.
Carb loading before race day…
Which is the most important pre-race meal?
Is it breakfast the morning of the race?
Is it dinner the night before the race?
Should you even carb-load at all?
You have probably heard a number of opinions on how to fuel during race week. That’s largely due to sports nutrition being a relatively new science, along with the fact that everyone is unique in what they’re own body responds to. As a sports nutritionist, it can be hard to spruik a one size fits all approach.
Despite this, I do have a personal “over-arching” view which I have formed firstly via my nutrition training, secondly my assessment of endurance-related nutrition studies and probably most importantly, the anecdotal evidence gained by working with a range of endurance athletes in my sports nutrition practice.
Let’s start with a quick background on how fuel works in the body. When you consume a carbohydrate, the glucose molecules in the carb are connected by a bunch of bonds called glycosidic bonds. This is what forms glycogen in either muscles or the liver. The conversion of glucose into glycogen depends on the absorbability of the specific carbohydrate that you consume. Due to this it could take anywhere from 8 hours to about 24 hours for glycogen to be produced and stored into the muscle or liver.
Understanding this you will realise that the breakfast you eat on the morning of the race can really only produce a teaspoon or so of actual glucose that is in your blood-steam when you start the event. Very little of it is actually glycogen at that point. In fact, it’s most likely that your pre-race meal will either be sitting in the top of your stomach, slowly being released into your small intestine, or its already in your small intestine slowly getting released into your blood-stream. So it’s not going to be something you rely on as a huge source of energy but rather it will be a little bit of slow-releasing blood glucose.
Therefore, much of what you are going to rely upon for energy at the start of your race will be the glycogen that was formed from the previous day’s meals. That being considered, I therefore argue that breakfast the day before your event is in fact the most important pre-race meal.
You also need to consider this: exercise up-regulates what’s called glut4 transporters which are the non-insulin dependant transporters responsible for taking carbohydrates from food and transporting them into muscle tissue. Because we know this, I suggest that your pre-race nutrition strategy should in fact be coupled with a pre-race exercise strategy. And if you really want to round out your preparation, I also say you should combine all of the above with a pre-race sleeping strategy.
This week I’m in Cairns supporting a number of Elite Fit Food clients who are competing in Sunday’s Ironman. If you want to give my nutrition/exercise/sleep strategy a try, it would look something like this for IM Cairns:
This not only keeps your circadian rhythms steady but also keeps your cortisol production in order. Cortisol should be at its highest in the morning. It’s the hormone that helps you spring up out of bed and start your day. Teach your body that you want your cortisol spike sometime between 4am and 5am on Sunday morning, depending on how early you want to get to Palm Cove for check-in.
Thursday and Friday, eat nutritionally dense foods with a focus on good fats and fibre.
In the lead up to Sunday I realise the excitement of the event kicks in and for many the “festival” feeling of an IM event is high. Enjoy your eating as I know it feels like you’re on holidays. But stay focussed on eating quality fresh foods that don’t stray too far from your standard diet. On Sunday you will drastically deplete your water soluble vitamins so stay topped up in the days before to compensate. Slightly increase good fats and fibre on these days as will reduce them the day before race day. We do this to minimise gut issues that can be caused by too much fat and to reduce the amount of un-excreted fibre sitting in the intestinal tract the morning of your race.
Saturday morning exercise in a fasted state.
Remember what I said about exercise being an up-regulator of glute4 transporters? Well, this is how you implement a strategy of leveraging glute4:
Wake at your IM race day time. Most people won’t have checked their bike into transition yet, so take advantage of still having your bike and head out for an easy spin session – nothing too intense – maybe 20 to 30 minutes. If you’ve been travelling in the days before you may like to shake out the legs with an easy 10-20 minute slow run off the bike. And if you’re really feeling it, you could finish the session with 10 to 20 minutes of basic drills in the pool. Then head in for breakfast. This is the time to have good carbohydrates to really replenish those glycogen stores with glut4 transporter assistance. Oats and sourdough bread are my favourite carbohydrate options. I’m also a fan of consuming quality protein at this time. For that, in my opinion you can’t go past eggs. Nix the avocado and/or Benedict sauce on this one because we want to keep fats reduced this close to race day.
Small frequent snacks throughout Saturday.
Engage in small frequent snacking the rest of Saturday to ensure you are not putting a big digestive load on the body, but rather gradually replenishing muscle glycogen throughout the day. Rapid fluctuations in blood sugar levels in general may not be the healthiest choice when it comes to glycation, inflammation, creation of reactive oxygen species via the use of glucose by-cells etc so take care not to overdo it. This is part of the reason why the old-school carb-loading protocols of past are no longer used by most sports nutritionists.
Saturday eat less fibre and fats to protect the GI tract.
Studies have shown that unless you are a “fat-adapted” athlete, ingesting too much fat and fibre the day before race day can create gut issues when under performance stress. To help combat this I recommend athletes reduce fats and fibre throughout Saturday. Instead focus on nutritionally dense, low FODMAP and simple carbohydrate foods such as rice, oats, sourdough bread, quinoa, green beans, bok choy, capsicum, broccoli, carrots, mushrooms, pumpkin, spinach, zucchini, bananas, berries, grapes, rockmelon and honeydew melon.
If you’re interested in giving this race week strategy a try but feel you need more information or guidance, then please get in touch.
Loren Turnbull of Elite Fit Food is a Sports Nutritionist who assists people to improve athletic performance by making good nutrition choices. Loren believes everyone should have the information they need to live a healthy life and strives to share her knowledge whenever possible.
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