By Dr. JIM FORBES, Chiropractor
With the Olympics in full swing, we're watching the best athletes perform amazing physical tasks to near perfection while pushing the limits of their physical activity.
Often overlooked is the nutrition needed to fuel these athletes and the most important energy source we have for physical activity are carbohydrates.
How much and how soon carbohydrates need to be consumed before, during, and after exercise?
Sub optimal nutrition can make even world champions perform at an amateur level. Follow these steps and use proper nutrition practices to your advantage.
Activities ranging from distance running, rowing, cycling, and avid weight training put excessive nutritional demands on the body.
It is not uncommon to train anywhere from 6 – 40 hrs per week at an intensity of 70% of our maximal capacity. Each hour of 70% max work requires roughly 1,000 calories for a male and 700 calories for a female.
Therefore, 8 hours of 70% exercise a week means we need an excess of 8,000 calories to meet our energy demands. If this need is not met then performance is compromised and gains in endurance capacity are decreased.
Why Do I Need Carbohydrates?
Carbohydrates are the main fuel for muscles and are the quickest and easiest form of energy to utilize in long distance events. Carbohydrates are stored in our muscles and in our liver, ready to supply our endurance activities.
How Much Carbohydrate Do I Need Every Day?
That depends on your activity level (how long and how hard you work). Included with this article is a chart that can help you determine the amount of carbs you should consume every day prior to activity. The starred / middle category is where most people fall into. The values are in grams of carbs required per kilogram of body weight per day.
How Much Carbohydrate Do I Need Before My Activity?
While sleeping overnight, we can completely deplete our liver stores of carbs. Therefore, prior to our activity we should consume 200-300 grams of carbs 3-4 hours prior to our activity. This will ensure that our carbohydrate muscle stores are full prior to activity.
How Much Carbohydrate Do I Need During My Activity?
Only 400-600 grams of carbs can be stored in the body to fuel muscular activity. Elite cyclists can deplete this in as little as 1 hour, therefore if our activity lasts longer than 1-2 hours we need to consume carbs during our activity. If this is the case, then you should consume 30 – 60 grams of carbs every hour of activity. For example, one 591 mL bottle of gatorade contains roughly 28 g of carbs.
What Type of Carbohydrate Should I Consume During Activity?
As mentioned above, if your activity lasts longer than 1-2 hours then you should consume carbohydrates during your activity. It is best to have glucose, sucrose, or combinations of glucose known as maltodextrins. There are a lot of carb mixes that are come in small gel like packs that put different carbs in certain combinations to increase the absorption by your intestines. This will ensure that more carbs are absorbed and less is hanging around in your intestines leading to less stomach upset.
How Much Carbohydrates Should I Consume After Activity?
The amount of carbs you need after exercise depends on the duration and intensity of your activity as well as when the next event will take place. However, you should always consume carbs as close to the completion of the activity as possible. Delaying eating by ~ 4 hours can decrease the availability of carbohydrate stores in muscle by 50%. This means that if you wait too long to eat following your last activity then you could be at a 50% deficit by the time you start your next activity. The golden rule is to:
- Consume 1.5 g / kg of body weight immediately after exercise
- And the same amount at 2 hour intervals following activity for 4 hours if you are involved in any form of endurance based exercise (running, cycling)
For example, a 154 pound male needs 420 grams of carbs over a 5 hour period, this is equivalent to 2 loaves of white bread! Remember, a carbohydrate requirement chart is available at the end of this article for you to determine how much you need. Print this out and enter your own values to ensure that you get the proper amount of carbs. Put this on your fridge and set aside separate meals that you consume pre, during, and post activity.
- Ensure you are getting the proper amount of carbs for your activity level.
- Consume < 200 g of carbs 3 – 4 hours prior to activity
- Consume 1.5 g / kg body weight immediately after exercise.
- The same amount should be consumed at 2 and 4 hour intervals if your involved in endurance exercise (running, rowing, cycling, etc)
Proper nutrition is the easiest way to get the most out of your body and your training. Follow these steps to ensure that you’re physical performance is not hindered by poor nutrition.
CARBOHYDRATE AND FLUID REQUIREMENT CALCULATOR
1) _____ lbs (your weight) X 2.2 = _____ weight in kg
2) Daily requirement of carbohydrates.
Recommended Carb Intake
Light Training (<1hr. of low intensity exercise per day)
5 – 7 grams of carbs per kg of
body weight per day
Typical Training (1-4 hrs. of moderate to high intensity exercise per day)
7 – 12 grams of carbs per kg of
body weight per day
Extreme Training (>4 hrs. per day of moderate to high intensity exercise)
10 – 12 + grams of carbs per kg of
body weight per day
3) Must consume 200 – 300 grams of carbs 3-4 hrs prior to event.
4) Must get 400 – 600 ml of fluid every 2 hours of event.
5)*_____ ml of fluid per hour of event.
* pre determined or estimated amount in ml required to lose less than 1% body mass during event.
6)____ml (from # 5) X 0.075 = ___ grams Carbs per hour during event (if event lasts > 1 hour)
7)1.5 grams X ___ (kg body weight) = ___ grams of Carbs needed immediately after event and every 2 hours for 4 hours.
8)___ lbs lost during event X 1.5 = ___ lbs / 2.2 = __ L of water needed after event. *Ensure there is sodium in the fluid / solid you are consuming (don’t drink water alone!)