Carb-loading: From the lab to your mouth
In my last post, I outlined the evidence supporting pre-race carb-loading for runners targeting the marathon (or perhaps half-marathon) distance. Based on current research, athletes should attempt to eat 7-10 grams of carbohydrate per kg body mass per day, for 1-2 days, in order to maximize muscle glycogen stores before exercise.
If you don’t know if you’d be able to handle that much carbohydrate, or if you still just aren’t sure if carb-loading is for you, let’s simplify things even further with these two key points for the day or two leading up to your race:
#1: Eat more carbohydrate than you normally do on a given day. Not necessarily a lot more; just more.
#2: Consume carbohydrate at regular intervals throughout the day, and avoid feelings of extreme hunger or extreme fullness.
If you are sure you want to try carb-loading before your next race (or better yet, before a long training run first!), here is an account of my own experiences: A couple months ago, I tried to eat 8 grams of carbs per kg body mass, or 600 grams total (2400 calories). Here’s how I did:
Breakfast 7am: Bagel with PB and jam, banana, coffee with sugar: 50g+25g+5g =80g
Mid-morning 10am: Apple, 2 yogurt cups, granola bar: 20g+40g+45g = 105g
Lunch 12pm: Pasta with meat sauce, 2 slices bread, 500mL sports drink: 70g+30g+30g = 130g
Mid-afternoon 2pm: 500mL sports drink, 3 granola bars: 30g+45g+58g = 133g
I was at work and had already run out of quality food options.
Dinner 5pm: Chicken and rice stir fry and salad: 75g+5g = 80g
Dessert 7pm: Smoothie: 1 cup chocolate milk, 1 yogurt cup, frozen raspberries and a banana (smaller than the first banana): 26g+20g+10g+20g = 76g
My total carbohydrate intake for the day was right around 600g, or 8 grams per kg body weight. I actually felt I could have eaten a bit more, which is perhaps not surprising since my normal daily carb intake is high. As I mentioned before, it may be more important to simply eat more carbs than normal, compared to getting an exact amount. Here are a few other practical insights I gained:
I was working at the Running Works in downtown Guelph for most of the day, so I had to bring things that were quick and easy. This is something to keep in mind if you’re going to be traveling or away from home the day before your race. Bananas, apples, granola bars and yogurt cups are portable, easy to eat, and a good source of carbs.
Getting plenty of liquid carbs was very helpful in order to ensure I got enough total carbs, while also avoiding feelings of extreme fullness. You could easily replace the sports drink with some type of juice if that is preferred.
Eating at regular intervals was crucial. This ensured that I never felt too full or too hungry, and that I didn’t need a huge meal at dinner.
Carbs for race morning
I mentioned that carbohydrate gets stored in your body in two places: in the muscles, and in the liver. Carb-loading for 1 to 2 days before your event ensures that your muscle glycogen levels are high to start the race. On race morning, your pre-race breakfast will ensure that your liver glycogen is topped up. A pre-race breakfast should provide about 2 grams of carbs per kg body mass (give or take) in the final 1-3 hours before exercise. Choosing carbs with a low glycemic index (GI) may improve performance compared to eating high-GI foods, but the only studies to find this were studies in which subjects were not allowed to consume any carbohydrate during exercise. The most important things to keep in mind are to eat foods that you know agree with your stomach, and to not eat so much that you feel full before you start your event. Sorry if I start to sound like a broken record, but it really is important: Find a balance between too much and too little, and continue to experiment and find out what works best for you.
References
Wong S et al. Effect of glycemic index of pre-exercise carbohydrate meals on running performance. Eur J Sport Sci 2008;8:23-33.
If you don’t know if you’d be able to handle that much carbohydrate, or if you still just aren’t sure if carb-loading is for you, let’s simplify things even further with these two key points for the day or two leading up to your race:
#1: Eat more carbohydrate than you normally do on a given day. Not necessarily a lot more; just more.
#2: Consume carbohydrate at regular intervals throughout the day, and avoid feelings of extreme hunger or extreme fullness.
If you are sure you want to try carb-loading before your next race (or better yet, before a long training run first!), here is an account of my own experiences: A couple months ago, I tried to eat 8 grams of carbs per kg body mass, or 600 grams total (2400 calories). Here’s how I did:
Breakfast 7am: Bagel with PB and jam, banana, coffee with sugar: 50g+25g+5g =80g
Mid-morning 10am: Apple, 2 yogurt cups, granola bar: 20g+40g+45g = 105g
Lunch 12pm: Pasta with meat sauce, 2 slices bread, 500mL sports drink: 70g+30g+30g = 130g
Mid-afternoon 2pm: 500mL sports drink, 3 granola bars: 30g+45g+58g = 133g
I was at work and had already run out of quality food options.
Dinner 5pm: Chicken and rice stir fry and salad: 75g+5g = 80g
Dessert 7pm: Smoothie: 1 cup chocolate milk, 1 yogurt cup, frozen raspberries and a banana (smaller than the first banana): 26g+20g+10g+20g = 76g
My total carbohydrate intake for the day was right around 600g, or 8 grams per kg body weight. I actually felt I could have eaten a bit more, which is perhaps not surprising since my normal daily carb intake is high. As I mentioned before, it may be more important to simply eat more carbs than normal, compared to getting an exact amount. Here are a few other practical insights I gained:
I was working at the Running Works in downtown Guelph for most of the day, so I had to bring things that were quick and easy. This is something to keep in mind if you’re going to be traveling or away from home the day before your race. Bananas, apples, granola bars and yogurt cups are portable, easy to eat, and a good source of carbs.
Getting plenty of liquid carbs was very helpful in order to ensure I got enough total carbs, while also avoiding feelings of extreme fullness. You could easily replace the sports drink with some type of juice if that is preferred.
Eating at regular intervals was crucial. This ensured that I never felt too full or too hungry, and that I didn’t need a huge meal at dinner.
Carbs for race morning
I mentioned that carbohydrate gets stored in your body in two places: in the muscles, and in the liver. Carb-loading for 1 to 2 days before your event ensures that your muscle glycogen levels are high to start the race. On race morning, your pre-race breakfast will ensure that your liver glycogen is topped up. A pre-race breakfast should provide about 2 grams of carbs per kg body mass (give or take) in the final 1-3 hours before exercise. Choosing carbs with a low glycemic index (GI) may improve performance compared to eating high-GI foods, but the only studies to find this were studies in which subjects were not allowed to consume any carbohydrate during exercise. The most important things to keep in mind are to eat foods that you know agree with your stomach, and to not eat so much that you feel full before you start your event. Sorry if I start to sound like a broken record, but it really is important: Find a balance between too much and too little, and continue to experiment and find out what works best for you.
References
Wong S et al. Effect of glycemic index of pre-exercise carbohydrate meals on running performance. Eur J Sport Sci 2008;8:23-33.