The Ultimate Guide To Carb Loading: Avoid These Surprising Mistakes!
Today I’m going to talk you through the ins and outs of carb loading. What is carb loading? How to carb load? Does carb loading even work? I’ve got the answers to all your questions, right here.
Carbo loading has the potential to significantly improve your run time in many endurance events, so it’s definitely worth doing.
However, if done incorrectly, it also has the potential to cause a lot of unpleasant gastro symptoms like bloating, diarrhoea or abdominal cramps.
That is why we’re going to cover what good carb loaded foods look like, what you should avoid, how long before your race you should start doing it and plenty of other helpful tips.
This way, you can make sure that you are fulfilling your full athletic potential at your next endurance event!
What is carb loading: the truth behind carb loading myths!
This is a favourite topic of mine, because carb loading is such a powerful tool but it’s not as straightforward as a lot of people think!
Carb loading is NOT:
Eating a big pasta meal the night before
Eating a few more carbs than usual the day before your race
Going low carb first then carb loading before the race (this is no fun for your digestive system or your pre-race mindset!)
Carb loading IS eating a large and specific amount of carbohydrates in a good timeframe before your race, whilst avoiding or reducing certain food groups.
Why do runners carb load?
Let’s talk about the science behind carb loading and its benefits for runners in endurance events like marathons, triathlons and ironman races. I’ll also answer the big question: does carb loading work?!
So, the science: your body has two main sources of energy, fats and carbohydrates.
Fats are basically unlimited stores of energy, because the average person has over 50,000 calories worth of energy stored in fat.
However, carbohydrates are limited and the average person only has about 2,500 calories worth of carbs, stored in the body as glycogen.
When you run a marathon, a large proportion of energy is going to come from carbohydrates, which can run out if you are exercising for a long period of time - which is generally accepted as more than 90 minutes of hard, continuous exercise. This is why carbs have to be a big focus before and during your marathon.
By carbohydrate loading you are maximising or even exceeding your body’s usual store of glycogen, which is extremely helpful.
It basically reduces the chances of you ‘bonking’, or 'hitting the wall', which are terms used to describe getting to a critically low level of glycogen in your muscles, meaning you have to reduce your pace. Not to mention, how awful it feels to reach that stage!
Carb loading has been shown to improve endurance performance by about 2-3%. That might not sound like much, but look at the time differences it could make for you! They are pretty significant:
Performance benefit when carb loading, based on a 2% improvement
How much to eat when carb loading
Before we can discuss what to eat when carb loading, we need to look at how many carbs you should be consuming.
It is recommended that you eat about 10 grams of carbs per KG of bodyweight per day, which is actually quite a lot.
Let’s say you weigh 70 kilos, that’s 700 grams of carbohydrates.
For some perspective on this, this is how many carbs some popular carb-based foods contain:
1 Banana: 25g
250ml orange juice: 20g
2 slices white bread: 50g
1 energy bar: 25g
90g pasta: 60g
500ml energy drink (full sugar): 30g
6 gummy sweets: 25g
For a lot of people, the amount of carbs they have to eat for carbs loading comes as quite a surprise.
This is why it is so useful to have a plan in place. If you simply up your carb intake a bit compared to normal, by eating some more pasta or rice, you won’t get anywhere near the 10 grams per kilo mark needed for effective carbohydrates loading.
Carb loading foods: which foods are best for carb loading?
So now you know how much you need to eat, let’s talk about what the best carb loading foods for running and endurance events are.
This is important because the type of carbs you eat can have a significant impact on how well the carb loading goes and whether you get any sort of gastrointestinal upset during your race.
When offering every day nutrition advice, I usually suggest that you eat whole grain carbohydrates, because they are healthier overall.
But when it comes to carb loading this isn’t the case.
With carb loading, the simpler the carb, the better. This is one of the only times you’ll hear this from a nutritionist, so enjoy it: go for white bread over wholemeal bread, white rice over brown rice and make sure you include some sweets and sugary drinks in your food!
Kind of a treat, right?
The whole grain varieties contain more fibre, more protein and more fat, but your focus is pure carbs.
Those other nutrients are just going to make you feel more full and even bloated. Plus, there is a higher likelihood that they will still be around your gastro tract on the day of your marathon, meaning that they could contribute to an upset tummy on race day.
Sweets and carbohydrate-based drinks provide an easy way to consume high quantities of simple carbohydrates with minimal protein, fat or fibre in them. This is perfect as part of a carb load.
So stock up on your favourites and get munching.
You should still be eating full meals of course. Good carb loading meals include white pasta, simple rice dishes and plenty of toast.
I should mention: if you have an underlying health condition such as diabetes, eating this amount of processed carbs could be very dangerous. Speak to your doctor for advice on how best to carb load while managing your condition!
When to start carb loading: How to Achieve Optimum Timing!
The current evidence suggests that even 24 hours of proper carbing up is probably sufficient to maximise glycogen stores before something like a marathon.
A study compared muscle glycogen stores after 24 and 72 hours of carb loading and found no significant difference in the measurements.
In my opinion, it’s probably worth starting around 36-48 hours before the race. This gives your body enough time both to adjust to lower fibre foods, and to really build up a good reserve of glycogen.
You don’t need to go on a low carb diet before you start carb loading. We know you can get the same results in terms of glycogen storage, if you go from a standard diet straight into a carb loading diet.
If you go low carb first, you’ll probably just end up feeling physically grim, so I wouldn’t recommend it on any account.
Carb loading plan: plan for success!
I really advise that you follow a carb loading meal plan if you want to ensure the greatest success.
You can design one yourself, of course, but that can get a bit fiddly with all the calculations necessary.
I have a pre-made carb loading meal plan that you can download. It will show you exactly what to eat to make sure you hit the 10g per kilo of bodyweight mark and reduce the risk of gastro issues! The perfect race day prep!
4 Top Tips for Effective Carb Loading
Hydrate, hydrate, hydrate!
When you’re carb loading you need to keep an eye on your hydration too. From my personal experience and from working with athletes, it’s really common to feel more thirsty than usual when you are carb loading.
Keep an eye on your fluid intake and plan to drink a little more than usual. I usually add electrolyte tablets or some normal table salt to my drinks over the days when I’m carb loading.
Unless you have a specific medical condition and you’ve been advised not to do this, this shouldn’t be an issue.
Timing is everything
You don’t want to be eating loads of carbs in the evening - that can cause great discomfort! Eat more in the morning and afternoon so that you can eat relatively less in the evening. Pace yourself and it should all go smoothly. This is another way that meal plans can come in handy!
Drink your carbs
It is a good idea to include high-carb drinks in your meal plan (eg. Sports drinks). Literally eating the amount of carbs you need in order to carb load can be quite challenging and feel very heavy.
Sports drinks are a great alternative because they’re full of simple sugars as well as a bit of sodium, or salt, which will help with your hydration.
Practice makes perfect
My advice would be to practice carb loading once or twice, at least 2-4 weeks out from your race. Even if you just try it for 1 day, make sure you feel comfortable doing it and don’t get any digestive issues from the foods you have chosen.
This way you’ve got time to finetune your plan before race day.
Carb Loading FAQs
Before I go, let me answer a few quick fire questions that often come up around carb loading. If you have any more questions you’d like answered, drop me a line in the comments below and I’ll do my best to respond to them!
When should I start carb loading?
You should start carb loading around 36-48 hours before your endurance event. Studies show that anywhere between 72 and 24 hours in advance is a sufficient time period for carb loading.
I propose 36 hours as a good middle ground: enough time to store up glycogen and adjust to this dietary change.
What is carb loading for weight loss?
Carb loading isn't really helpful for weight loss, since weight loss is about being in a sustained calorie deficit - and carb loading isn't great for that!
You can temporarily lose weight by reducing or removing carbs, but that's just water weight changes rather than fat loss.
Is carb loading still recommended?
Yes! Carb loading is a proven effective method for improving performance in endurance events such as marathons and triathlons. When done right, carb loading can lead to a 2-3% performance improvement.
What is carb loading for muscle gain?
For carb loading for muscle gain, you should be eating in a slight calorie surplus, to give yourself the fuel to adapt and grow new muscles.
Carb loading won't specifically help with muscle gain - you need to follow best practices like progressive overload, consistent training and a good amount of protein in your diet.
Is carb loading a myth?
No! Carb loading is not a myth. It is an effective, and at times necessary, method of improving performance and ensuring you don’t hit a wall when participating in endurance events.
Your body needs more glycogen than usual to get through endurance events, and carb loading is a great way to build up glycogen reserves before a big race.
And that’s all you need to know about carb loading! Good luck on race day! Enjoy those sweet sweet simple carbs!
