Carbohydrates are kind of a big deal. What types you eat and when you eat them can greatly maximize training benefits! I often get questions from other runners and have questions myself about carbohydrates and so I thought I would pass along the words of wisdom I received today from Kyle Pfaffenbach, who came to Brooks headquarters to lead a "Nutrition Symposium". Kyle has a dual masters in Exercise Physiology and Nutrition as well as a Post Doc in how nutrition affects chemotherapy, and touched on many different topics including the timing of carbohydrate consumption.
- Maximizing glycogen stores is critical to performance, and efficiently restoring muscle glycogen post workout enhances recovery.
- Muscle glycogen storage capacity increases with training, and is a critical training adaption.
- Carbohydrates should typically comprise 45-50% of an athletes diet (5-10 g/kg or 20-40 cal/kg body weight per day) and in the 3-4 days leading up to a big race carbohydrate consumption bumped up to 60-70%.
- Quality sources of simple sugars include: fruits or Gatorade, Gatorade Prime, Cliffshot, Gu, Pwerade etc. the ingredients to look for are glucose, fructose and maltodextrin.
- Quality sources of complex carbohydrates include legumes, brown rice, oats and sweet potatoes.
- Simple sugars can be consumed immediately prior to exercise, and may increase carbohydrate availability and glycogen sparing and even act to blunt cortisol levels.
- Consumption of simple sugars immediately post exercise (within 30 minutes of workout ending) acts to maximize glycogen storage, increases anabolic hormones such as insulin and IGF1, enhances recovery, and allows for multiple hard training sessions per week.
- Training runs longer than 1 hour should be accompanied by simple carbohydrates supplementation (8-10 grams every 20-30 minutes) and DON’T start at 1 hour. If you know you’re going longer than 1 hour, still consume every 20-30 minutes.
- There is some evidence which suggests that small amounts of simple carbohydrates between intervals can increase glucose delivery to the muscle (like a small swig of Gatorade in between hard intervals of a workout).
- Consume complex carbohydrates 1-4 hours prior to hard workouts, particularly workout lasting longer than 1 hour. This will replenish liver glycogen and top of glycogen stores.
- In the 3-4 days leading up to an event (particularly longer events) increase carbohydrate consumption to 60-70% of total calories.
- For endurance athletes it is important to consume complex carbohydrates 1-4 hours prior to event, as this will allow your insulin levels to go up and come back down.
- It could be beneficial to consume small amounts of simple carbohydrates within 5 minutes of the event.
OTHER CARBOHYDRATE CONSIDERATIONS:
- Carbohydrate Rinsing: some evidence suggests that rinsing your mouth with a high carbohydrate beverage (Gatorade) during workouts and between high intensity intervals could improve performance.
- Avoid sugar alcohols- these are often added to beverages and protein bars to add a sweet flavor without adding calories. They are artificial sweeteners and provide no caloric value or energy. Examples include sorbitol, NutraSweet, aspartame, xylitol. You can check for these on food labels.
- Avoid high fructose corn syrup- a principle component of many highly processed foods such as sugary drinks, non-diet soda, and candy. It is metabolized by the liver differently than complex carbohydrates. Look for this on food labels and try to avoid it. (Fructose is different from high fructose corn syrup and can be used effectively in simple sugar beverages such as Gatorade prior to, during and immediately following exercise.)
- Outside of exercise, such as throughout the day, simple sugar drinks such as Gatorade and sports drinks should not be consumed.