MORE SUGAR PLEASE?
Is it time to start maximizing your carbohydrate intake during training?
I know simple sugars and a healthy diet don’t generally go together. I keep threatening to cut them out of my diet but can’t seem to shake those after-dinner cravings. I am working on it ;-).
On the other hand, there are actually some good reasons you might want to consume more of these simple carbs during exercise, especially when at the right time.
Fueling techniques for exercise can vary depending on the type of activity and the goals of the individual. Before delving deeper into the topic of fueling for endurance performance, here's a breakdown of fueling techniques DURING EXERCISE for various types of activities:
1. Endurance Performance:
Consume carbohydrates in the form of sports drinks, gels, or easily digestible snacks to maintain blood glucose levels and delay fatigue during prolonged endurance activities. Aim for 30-60 grams of carbohydrates per hour of exercise.
2. Strength Training:
Hydrate adequately with water or a sports drink if the workout is intense and prolonged. Consume carbohydrates if the session is particularly long or high-intensity.
3. HIIT Training (High-Intensity Interval Training):
Focus on staying hydrated with water since HIIT sessions are typically short.
4. CrossFit:
Stay hydrated with water or a sports drink. If the workout is particularly intense or prolonged, consider consuming carbohydrates in the form of sports gels or drinks.
5. Functional Training:
Focus on staying hydrated with water. Depending on the intensity and duration of the workout, consider consuming carbohydrates if needed to sustain energy levels.
6. Active Recovery:
Hydrate with water to replace fluids lost through sweating.
Typically, you will need to hydrate with water or electrolyte drinks, aiming for around 5-10 milliliters per kilogram of body weight every hour. For longer endurance events, determine your hydration needs by identifying your sweat rate on cool, warm, and hot days.
For those endurance athletes and adventurers who have an extensive event coming up on the horizon it might be time to start training up your ability to take in more fuel during exercise. It can definitely improve your performance to finish stronger in longer events if you can maximize the amount you take in.
Carbohydrates and Endurance Performance
For endurance athletes, ongoing research and discussions focus on the optimal carbohydrate intake for performance. Some trends recommend higher carbohydrate intake, specifically around or above 90 grams per hour, to optimize performance. Here's a summary of the latest findings and trends:
1. High Carbohydrate Availability During Exercise
Traditionally, it has been recommended to consume around 30-60 grams of carbohydrates per hour during prolonged endurance exercise to maintain blood glucose levels and delay fatigue. Recent studies suggest that higher carbohydrate intakes during exercise can enhance performance by providing more fuel for working muscles. Sports researcher Andrew Hamilton suggests,
"Much of the carbohydrate oxidized for fuel during exercise is derived from stored carbohydrate in the muscles (muscle glycogen). It just so happens that even a relatively modest drop in the levels of muscle glycogen can produce feelings of fatigue and tiredness, which is why a large body of research has demonstrated that keeping topped up with carbohydrates during prolonged exercise can help stave off fatigue."
2. Exogenous Carbohydrate Oxidation Rates
Research has shown that the body's ability to oxidize exogenous carbohydrates (carbohydrates consumed during exercise) can be significantly higher than previously thought, especially when multiple transportable carbohydrates are ingested simultaneously (e.g., glucose and fructose).
3. Glycogen Preservation
Consuming higher amounts of carbohydrates during exercise may help preserve muscle glycogen stores, which are a critical fuel source during prolonged activity. By sparing glycogen, athletes can maintain performance levels for longer durations.
4. Individual Variability
Carbohydrate requirements can vary significantly among individuals based on factors such as body size, metabolism, training status, and exercise intensity. Some athletes may tolerate higher carbohydrate intakes better than others for a variety of reasons. Oh, and btw, we can test your carbohydrate (CHO) needs in the lab to determine CHO per minute at various heart rates in zones 2 and 3. Check out our Metabolic Efficiency Profile (MEP).
5. Practical Recommendations
The trend towards higher carbohydrate intake during endurance exercise has led to practical recommendations suggesting intakes of 90 grams or more per hour, especially during ultra-endurance events or high-intensity efforts lasting several hours. This often involves consuming a combination of sports drinks, gels, bars, or other easily digestible carbohydrate sources.
6. Training the Gut
Just as athletes train their muscles for endurance, there's growing emphasis on "training the gut" to tolerate higher carbohydrate intake during exercise. This involves gradually increasing carbohydrate intake during training sessions to enhance gut absorption and minimize gastrointestinal discomfort. For example, if you are already consuming around 30 grams of carbohydrates per hour, you might want to add 10-20 grams to your fueling workouts (e.g., zone 2-3 longer workouts). Keep adding 10-20 grams to your intake every 2-3 weeks until you’ve reached your upper limit (e.g., 90 grams).
7. Timing and Formulation
The timing and formulation of carbohydrate intake also play crucial roles in optimizing performance. Consuming carbohydrates consistently throughout exercise, rather than waiting until fatigue sets in, can help maintain energy levels and performance. Additionally, choosing carbohydrate sources with a mix of glucose and fructose can enhance absorption rates.
8. Delivery Strategies
As you begin training to optimize fueling, you can also work on making the delivery system more efficient. Will you be mixing fuels with your fluids? How much of your upper limit (grams/hour) will be gels, chews, solid foods, etc.? Check out my Substack section on “During Exercise Fueling” to see a couple of videos on how athletes are delivering their fuels.
9. Alternative Carbs for GI Sensitive Athletes
Products on the market may make it easier to optimize fueling even if your gut is not cooperative. UCAN is a brand that produces a line of sports nutrition products, notably Super Starch, which is a patented, slow-releasing complex carbohydrate derived from non-GMO corn. This product is often marketed to endurance athletes due to its purported ability to provide sustained energy without causing spikes and crashes in blood sugar levels. Other products like hydrogels claim to limit GI issues due to two thickening agents that are pH-sensitive, which can suspend carbohydrates for potentially smoother transport through the stomach and into the intestines. However, studies on hydrogels to this point have not shown much significant difference in gut sensitivity responses compared to more typical glucose/fructose mixes.
Overall, the latest research and trends suggest that higher carbohydrate intakes during endurance exercise, potentially around or above 90 grams per hour, can benefit performance by providing additional fuel for working muscles and preserving glycogen stores. However, individualized approaches and practical considerations are crucial, and athletes should experiment with different strategies during training to determine what works best for them. Also important to remember is that you might want to lower your overall carbohydrate intake (especially simple carbs) during blocks of low intensity or non-preparatory phases of training to optimize your metabolic health.
Supporting Research
Sports Med. 2022; 52(Suppl 1): 5–23: Carbohydrate Research: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9734239/
Nutrients. 2023 Mar; 15(6): 1367. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10054587/
For a quick review of your fuel and hydration needs check out the fuel tools below: