Carb loading is a term used frequently in running and endurance circles but what does it actually mean? Put simply, it the process of increasing the amount of calories you consume from Carbohydrates in order to maximize the amount of Glycogen in your muscles. This is essential in endurance events as Glycogen will be your main fuel source and is most efficiently converted into energy. Once depleted, you will be forced to burn fat and finally muscle which won't provide the same amount of energy and is slower to metabolise meaning you will find activity much more challenging despite levels of fitness.
Historically, it was advised to completely deplete Glycogen stores by consuming a low carb diet for around 4 days, then switching to high carbs to refill. Thankfully, more modern research has demonstrated there is no need to empty first (which is a great thing for all us Carb lovers!)
So how much Carbohydrate actually constitutes loading - well, it varies from person to person but typically you should aim for 4 grams of Carbs for each KG of body weight. So, if you weigh 60 kg then you would need 240g. Each gram of carbohydrate is 4 calories (on average) so this is a total of 960 calories. You can start loading from 5 days out - I personally plan to start tomorrow as my diet is already pretty carb heavy. Try to distribute your intake evenly throughout the day and by meal to get the most from your diet.
You can get some level of Carbs from pretty much every food group out there (meat and fish being the exception for the most part) however the volume and quality varies dramatically. Below I have rounded up the highest carb containing foods by group, along with their volumes for reference. By focusing on these foods, you can ensure you're able to hit the needed intake amounts as focusing on lesser carb heavy foods, you will become full before hitting the requirement.
|Fruit||Measure||Carb content in Grams|
|Vegetables||Measure||Carb content in Grams|
|Sweet Potato||1 Whole||28|
|Grains||Measure||Carb content in Grams|
|Bagel||1 Whole||35 - 50|
|Cous Cous||1 cup||36|
|English Muffin||1 Whole||25|
|Muffin||1 Whole||29 - 28|
|Beans||Measure||Carb content in Grams|
|Baked Beans||1/2 Cup||24|
|Misc||Measure||Carb content in Grams|
|Frozen Yogurt||1 Cup||36|
|Cake||1 piece||34 - 50|
Note that I whilst have included some desserts, the Carbs here come pretty much entirely from sugar which will be expended much quicker than those in whole foods. However, given what we're about to undertake, a little indulgence is as good for the body as it is for the mind!
Good luck to everyone running London or any other race this weekend - remember, all the hard work has already been done so relax, smile and enjoy!