The Truth Behind Carb-Loading Before a Race.


If you’ve been in the running scene long enough, chances are you’ve heard about loading up on carbohydrates the night before a race. Why do they suggest doing this? The main reason is to make sure your body has a lot of simple sugars floating around that can easily be burned for energy. Carbohydrates are much more readily used than fats or proteins so it makes sense to have plenty of carbs before a race, right? Well, it depends on two factors; how long the race you’ll be running is and what your eating habits have been in the weeks prior to the race.

When it comes to carbohydrates, it doesn’t take very long for them to be ready for energy use after consuming them. This means that eating carbs even an hour or two before your race will ensure that they will be used during the run.

Race Distance

On average, we burn 110 calories per mile while we run. Carbo-loading can be helpful for very long races, anything that will take over two hours to complete, because we will deplete all carbs we have stored in that time. For the most part, this means a half marathon or further. Eating 1000 calories of spaghetti the night before a 5k is going to be too much energy stored for the race and that excess energy will end up turning in to fat. With shorter races, those taking under an hour, you don’t need to change your eating habits very much. While it is recommended that you avoid a high protein or high fat meal the night before a morning race because they take longer to digest, you don’t need to take in more calories to prepare for the race. If the race is later in the day, you don’t have to change your eating habits the night before at all.

Eating Habits while Training

When it comes to racing, your body’s physiology doesn’t know if your race in 2 hours or two weeks. It will continue to work like it normally does until a stressor is put on it. Once there is a stressor, your body will adapt to ensure it can handle the new challenge. This is the idea when it comes to training. Increase mileage or add workouts to your regimen to build muscle strength and increase lung capacity. When you run a workout, your muscles break down and, assuming you eat enough protein, will rebuild to be slightly stronger than before. This concept is like how nutrient absorption works, especially when it comes to carbohydrates.

If you want to get a significant benefit from carbo-loading, you need to put a stressor on the body. The most effective way to do this is to reduce carbohydrates from your diet for a few weeks before your race. Doing this will tell the body that it needs to increase carbohydrate absorption and carbohydrate storage capacity. Once your body is in this state, you will be able to gorge on carbohydrates and your body will hold on to significantly more of those simple sugars than it normally would. Now you are ready to race!

At this point you may be thinking, “Isn’t it going to hurt your training if you cut out carbs weeks before the race?” It shouldn’t. Your body has other means of getting energy, such as ketosis, that it shouldn’t have an impact on performance. Three weeks before the race should also be when your taper begins so the training will be lighter. An impact it could have is on your attitude and mentality. Being starved of carbohydrates can leave you feeling tired, crabby, and irritable. This occurrence is normal while your body learns to transition to a different energy source. The bad attitude will generally last a week or two and should be gone in time for race day.pasta_man

When it comes to effective carbo-loading, you need to ask yourself one question; Is my performance in this race so important that I should go through the pains of carbohydrate deprivation just to optimize my glycogen stores? If the answer is “no” or “what on earth did he just say?”, then eat like you normally would but replace some proteins and fats for carbs for your pre-race meal. Also, if you do want to go the carbo-loading route, contact your medical practitioner or a nutritionist before making a major dietary change while training.

This post is just the tip of the iceberg when it comes to food and nutrition while training and on race day. If you have questions about the blog post or want me to write about other aspects of nutrition while training, please write a comment to this blog and let me know! Or let me know via twitter or on facebook.

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