Max out: Work your abs
5min reading
For many endurance athletes, dealing with a troublesome stomach is unfortunately almost expected. However, there are strategies you can use to address these issues or simply prepare your stomach for a higher intake than you previously managed. Just as you enhance your training with tougher intervals, more anaerobic sessions, and competition-paced workouts before the season, you can "train your stomach" to tolerate higher energy intake.
Why should you practice energy intake?
The principle of specificity is a common concept in training science, meaning "you become good at what you train." The same applies to our energy absorption. The body adapts to what we expose it to; if we consume a lot of fat, it becomes better at using it as fuel, and if we increase carbohydrate intake, this absorption becomes more efficient. You can read more about why focusing on carbohydrates is crucial for endurance athletes here. Briefly, the body works more efficiently with carbohydrates since they require 5-7% less oxygen to burn compared to fatty acids. 5-7% may not sound like much, but it actually translates to 10 extra heartbeats to maintain the same speed. And we all know how significant those 10 extra heartbeats can feel! Glycogen stores deplete ⇒ More oxygen is needed for energy extraction from fat ⇒ Heart rate rises ⇒ You hit your threshold = Hit the wall. Alternatively, you slow down to keep your heart rate at the right level, which we also refer to as hitting the wall, i.e., a sudden drop in intensity/speed. It isn't an on/off function where the heart rate suddenly rises by 10 beats when glycogen is depleted; rather, it will gradually climb as stores deplete (heart rate drift). This is very unnecessary, especially during competitions when it's not so complicated to adapt the system to handle more energy. In broad terms, the preparations involve teaching the body to handle more oxygen-efficient carbohydrates. Increased carbohydrate intake during activity saves stored muscle glycogen, which in turn helps you avoid hitting the wall. Practicing energy intake is also crucial technically and tactically. Getting into the habit of drinking or using gels effortlessly is key to sticking to the energy plan. But what about my fat adaptation?
During training or competition, the absorption of carbohydrates by the muscles is largely independent of insulin. Insulin secretion is nearly nullified as carbohydrates are absorbed and burned directly by the muscles due to the "back pressure" created when muscles are depleted of glycogen. This is one reason you become fat-adapted despite consuming sports drinks. While insulin usually slows fat oxidation and regulates up carbohydrate burning, since carbohydrates are metabolized without insulin during training, you still achieve significant fat adaptation (70-80%). Smart, right? So how do you do it?
It takes about 4 weeks to become nutritionally adapted for competition. The basic rule is to train more specifically for competition (both physically and nutritionally) at least 1 month before it starts. Changes in our body aren't instantaneous. Hormones, transport proteins, and enzymes, all involved in our metabolism, are slowly regulated up or down depending on diet and training setup. Studies show it takes about 4 weeks for the body to train up carbohydrate absorption when adapting metabolism for competition. If carbohydrate intake has been low, the body's ability to process them declines; shifting from low to high competition-specific carbohydrate intake suddenly can lead to classic stomach issues. In science, this downregulation of carbohydrate metabolism is evident when examining athletes who avoid carbohydrates for 3 days and then consume sports drinks. The athletes already develop some glucose intolerance after 3 days, with muscles less efficient at carbohydrate absorption and more inclined to store them rather than using them for energy immediately. In a study from 2010, a simple setup was used. Athletes were divided into two groups, both cycling for 100 minutes on a stationary bike. One group drank 375ml/hour of a 10% sports drink solution, consuming 60g of carbohydrates during the session. This group also received 1.5g of carbohydrates/kg body weight (112.5g) extra via diet for each training hour during these 4 weeks. The other group used only water during training but trained equally. Apart from that, all participants followed an equivalent isocaloric diet, meaning the same total energy intake for all participants every day. They changed just one small thing, or rather two, adding extra carbohydrates in the diet and sports drinks during sessions, significantly improving carbohydrate absorption and energy utilization by 16%. Their oxidation increased from 55g/hour to 65g/hour (of glucose alone). It may not seem much, but an extra 10g every hour during endurance events adds up to considerable oxygen savings. Practical Tips
- Increase carbohydrate intake in 1-3 sessions per week before the competition season
- Increase intake during endurance sessions and test the intended energy plan during speed sessions.
- Combine increased energy intake with competition-specific sessions.
- Test your limits. Do you usually manage 80g of carbohydrates per hour during competition? Try 100g/h during training.
The principle of specificity is a common concept in training science, meaning "you become good at what you train." The same applies to our energy absorption. The body adapts to what we expose it to; if we consume a lot of fat, it becomes better at using it as fuel, and if we increase carbohydrate intake, this absorption becomes more efficient. You can read more about why focusing on carbohydrates is crucial for endurance athletes here. Briefly, the body works more efficiently with carbohydrates since they require 5-7% less oxygen to burn compared to fatty acids. 5-7% may not sound like much, but it actually translates to 10 extra heartbeats to maintain the same speed. And we all know how significant those 10 extra heartbeats can feel! Glycogen stores deplete ⇒ More oxygen is needed for energy extraction from fat ⇒ Heart rate rises ⇒ You hit your threshold = Hit the wall. Alternatively, you slow down to keep your heart rate at the right level, which we also refer to as hitting the wall, i.e., a sudden drop in intensity/speed. It isn't an on/off function where the heart rate suddenly rises by 10 beats when glycogen is depleted; rather, it will gradually climb as stores deplete (heart rate drift). This is very unnecessary, especially during competitions when it's not so complicated to adapt the system to handle more energy. In broad terms, the preparations involve teaching the body to handle more oxygen-efficient carbohydrates. Increased carbohydrate intake during activity saves stored muscle glycogen, which in turn helps you avoid hitting the wall. Practicing energy intake is also crucial technically and tactically. Getting into the habit of drinking or using gels effortlessly is key to sticking to the energy plan. But what about my fat adaptation?
During training or competition, the absorption of carbohydrates by the muscles is largely independent of insulin. Insulin secretion is nearly nullified as carbohydrates are absorbed and burned directly by the muscles due to the "back pressure" created when muscles are depleted of glycogen. This is one reason you become fat-adapted despite consuming sports drinks. While insulin usually slows fat oxidation and regulates up carbohydrate burning, since carbohydrates are metabolized without insulin during training, you still achieve significant fat adaptation (70-80%). Smart, right? So how do you do it?
It takes about 4 weeks to become nutritionally adapted for competition. The basic rule is to train more specifically for competition (both physically and nutritionally) at least 1 month before it starts. Changes in our body aren't instantaneous. Hormones, transport proteins, and enzymes, all involved in our metabolism, are slowly regulated up or down depending on diet and training setup. Studies show it takes about 4 weeks for the body to train up carbohydrate absorption when adapting metabolism for competition. If carbohydrate intake has been low, the body's ability to process them declines; shifting from low to high competition-specific carbohydrate intake suddenly can lead to classic stomach issues. In science, this downregulation of carbohydrate metabolism is evident when examining athletes who avoid carbohydrates for 3 days and then consume sports drinks. The athletes already develop some glucose intolerance after 3 days, with muscles less efficient at carbohydrate absorption and more inclined to store them rather than using them for energy immediately. In a study from 2010, a simple setup was used. Athletes were divided into two groups, both cycling for 100 minutes on a stationary bike. One group drank 375ml/hour of a 10% sports drink solution, consuming 60g of carbohydrates during the session. This group also received 1.5g of carbohydrates/kg body weight (112.5g) extra via diet for each training hour during these 4 weeks. The other group used only water during training but trained equally. Apart from that, all participants followed an equivalent isocaloric diet, meaning the same total energy intake for all participants every day. They changed just one small thing, or rather two, adding extra carbohydrates in the diet and sports drinks during sessions, significantly improving carbohydrate absorption and energy utilization by 16%. Their oxidation increased from 55g/hour to 65g/hour (of glucose alone). It may not seem much, but an extra 10g every hour during endurance events adds up to considerable oxygen savings. Practical Tips
- Increase carbohydrate intake in 1-3 sessions per week before the competition season
- Increase intake during endurance sessions and test the intended energy plan during speed sessions.
- Combine increased energy intake with competition-specific sessions.
- Test your limits. Do you usually manage 80g of carbohydrates per hour during competition? Try 100g/h during training.
Summary
Your body adapts to what it's exposed to. If you train and live in a certain way, your body will align with that. If you're someone who experiences discomfort with fluid intake and/or energy, we recommend simply training on your weaknesses. The stomach will stabilize, and what was once a concern will become your strength. Begin training with carbohydrate intake during sessions, at least 4 weeks before your first competition of the season.
This can significantly enhance your carbohydrate oxidation, providing more energy, delaying fatigue, and reducing the risk of stomach issues. In the study we mentioned earlier, sports drinks or other carbohydrate-rich sources were used during sessions + some extra carbohydrates in the diet. For you, it's essential to push the individual intake limit by consuming a dose that challenges your capacity. This forces the body to optimize its absorption function and enhance carbohydrate utilization. Just like you sometimes train beyond your threshold to improve, not just engage in average sessions.
Your body adapts to what it's exposed to. If you train and live in a certain way, your body will align with that. If you're someone who experiences discomfort with fluid intake and/or energy, we recommend simply training on your weaknesses. The stomach will stabilize, and what was once a concern will become your strength. Begin training with carbohydrate intake during sessions, at least 4 weeks before your first competition of the season.
This can significantly enhance your carbohydrate oxidation, providing more energy, delaying fatigue, and reducing the risk of stomach issues. In the study we mentioned earlier, sports drinks or other carbohydrate-rich sources were used during sessions + some extra carbohydrates in the diet. For you, it's essential to push the individual intake limit by consuming a dose that challenges your capacity. This forces the body to optimize its absorption function and enhance carbohydrate utilization. Just like you sometimes train beyond your threshold to improve, not just engage in average sessions.