Are you effectively carb loading?

Over the past 50 years, a significant amount of research has shown the important role of glycogen for delaying fatigue in athletes competing in endurance and ultra endurance events. Glycogen is the storage form of carbohydrates. In humans, small amounts of glycogen are also found in tissues and cells, like the kidneys, red blood cells and brain. Glycogen is primarily stored primarily in the cells of the liver (~100g) and skeletal muscle (~500g). Skeletal muscles transform chemical energy to mechanical work. Glycogen is the body's predominant source of energy during moderate to high intensity activity. The depletion of muscle glycogen during endurance activity causes early fatigue. 

Dietary carbohydrates are converted to glucose - the main source of energy for the body and brain. For the non-diabetic population, when you eat a carb-rich meal, your blood glucose will rise. Increased blood glucose signals the pancreas to produce insulin - a very important hormone that helps the body cells take up glucose from the bloodstream to be used for immediate energy or for storage. Insulin tells the liver and muscle cells to produce the enzyme glycogen synthase that links chains of glucose together to form a glycogen molecule to be delivered to the liver and muscles. 

Because glycogen has a limited storage capacity, the intake of carbohydrates is extremely important for endurance athletes. High muscle glycogen content improves high intensity and endurance performance by increasing the time to fatigue. Due to the high demand for glycogen as an energy source, many athletes stay in a state of low glycogen depletion. Trying to complete high intensity or high volume workouts in a state of very low glycogen can increase the risk for damaged muscle tissue, immune system suppression and injury. Thus the importance of proper fueling, nutrient timing and understanding daily energy needs to support the current training load. And for all this to happen, the athlete must have a good relationship with food and the body. 

The heavily researched topic of carb-loading focuses on increasing the content of stored glycogen in an anticipation for the upcoming endurance event. Maximizing glycogen stores can help reduce fatigue in events lasting longer than 90-minutes. 

There are a lot of misconceptions around carbo-loading and a few key considerations to help you get the most out of glycogen supercompensation. 

• Muscle damage limits the capacity of the muscle to store glycogen, even while consuming a high carbohydrate diet. If you go into a race with damaged muscles (ex. downhill running, back-to-back racing), don't assume that a high carbohydrate diet will magically make your muscles perform/feel better. 
• Most of the research on carb-loading is on men. But there is a little research showing that females may require a slightly different pre-race fueling strategy due to metabolic differences from different hormonal profiles (specifically estradiol). Whereas men are advised to increase carbohydrate intake before a race, women are advised to increase carbs and calories. In other words, women may need to "energy load." 
• Muscle glycogen concentration is dependent on the diet. The higher carb intake in your diet, the higher the glycogen stores. 
• Training increases the amount of glycogen that can be stored in the muscle. Endurance training increases muscle glycogen stores and reduces the reliance on glycogen as a result of increased use of free fatty acids by active muscle cells. This metabolic adaptation allows your body to become more efficient at storing glycogen while also becoming more metabolically efficient. 
• After prolonged intense exercise, muscle glycogen levels may fall from 150-200 mmol/kg wet weight to <50 mmol/kg wet weight. When muscle glycogen levels fall to less than 70 mmol/kg wet weight, calcium release from the sarcoplasmic reticulum is impaired - which impacts muscle function, power output and performance. 
• Muscle glycogen resynthesis is a very slow process. It may take several days of rest or very light training (along with a higher carb diet) for muscle glycogen levels to reach adequate levels after several days of hard training. Consuming a high carbohydrate diet is critical to meet the demands of high volume/intensity training. 
• Carbo-loading should not be confused with overeating. Effective glycogen loading should the the result of emphasizing more energy-dense, low fiber carbohydrate sources and reducing fat intake alongside reducing (not stopping) energy expenditure (tapering). 
• One to two days of carbohydrate loading is sufficient to prepare your muscles for the upcoming event. 
• Glycogen depletion is considered an important limiting factor to performance. But eating more carbohydrates will not make you a better trained athlete. However, just because you didn't complete your  training as planned, this doesn't mean that you need to punish your body by underfueling. 

Carb-Loading Tips

• A carbohydrate intake of 5-7g/kg/day in the 1-2 days before your endurance event is recommended. 
• If you have a sensitive stomach or are prone to GI issues, be strategic with the foods you consume. Opt for a low-residue diet. 
• Males should aim for ~70% of the daily diet from carbs (without making a major change to caloric intake). A female athlete should aim to eat ~70% from carbs with an additional 30% increase in normally consumed calories. 
• Carbo-loading does not remove the need to stay well-fueled and hydrated throughout your event. Carb-loading is designed to help delay fatigue - not avoid fatigue. 
• Consume small meals, regularly throughout the day. Create a schedule (and plan) for eating so that you don't forget to eat or go long hours without eating. 
• If you feel "heavy" when you carb-load, this is good. This reflects the water weight that is added from glycogen storage. For every gram of glycogen stored in your body, you store ~3 ounces of water. This is ok! It doesn't have to do with a gain in body fat but water weight. This is also why people immediately lose weight on a low-carb diet. 
• Aim to eat your largest carb meals in the morning hours (breakfast - lunch) to allow more time for digestion. 
• Stay well-hydrated throughout the day to help with digestion. 
• Practice with similar pre-race foods in training to build familiarity and confidence for race day. 

Sources: 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566225/
https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP280221

https://www.220triathlon.com/training/nutrition-training/do-female-athletes-need-to-carb-load-more-or-less-than-male-ones-before-a-race/
https://www.mysportscience.com/post/carb-loading
https://www.scienceforsport.com/carbohydrate-loading-for-endurance-still-a-good-practice/

Is fat burning undermining your performance?

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The media loves to make nutrition simple. Workout fasted and you burn more fat. If only it was this simple. 

When it comes to the physiology of the body during exercise, nutrition is a complex topic. Researchers are still studying the different effects of nutrients, nutrient timing and supplements on exercise and exercise performance. This isn't to say that fat burning doesn't work (it does!) but it's not as simple as not eating carbohydrates before and during a workout. 

There's a lot of debate about fasted training, training low, LCHF diets, keto and low carb. Unfortunately, with no middle ground, athletes tend to direct their energy and attention to what's most trendy and popular and for the past few years, carbohydrates have received a bad reputation from the media. 

I am a proponent of carbohydrates in the diet. I feel strongly for nutrient timing (eating before/after workouts) and I believe that the use of sport nutrition is critical in optimizing health and performance for endurance athletes. But this doesn't mean that I prescribe eating all the carbohydrates, anytime and of any kind. But I am also a proponent of fat, protein, vitamins, minerals and water. In other words, fueling for sport performance is not black or white. If you sit on either end of the spectrum you could be sabotaging your performance and compromising your health. 

I'd like to start off with some not so breaking news that often gets overlooked when it comes to fat burning. 

• Through endurance training, you will increase fat oxidation by upregulating the enzymes of the fat oxidation pathways, increasing mitochondrial mass, increasing oxygen update and improving economy of movement. 
• To become a better athlete (ex. faster, stronger, more powerful), your physiology needs to change. While some individuals may experience a performance boost because of an improvement in health, the diet or body composition, a race weight means nothing if you haven't done the work to significantly change your physiology and to arrive to the race in an optimal state of mental and physical health. 
• Don't underestimate the importance of the relationship between your lactate threshold, economy of movement and VO2max. Having a lean or muscular body or performing workouts in a fasted state does not ensure that you are economic and able to quickly oxidize carbohydrates (without GI distress) to optimize performance. 
• Carbohydrates are the primary fuel produce ATP (energy). But you also need to keep up with your hydration (water and sodium) needs in the face of sweat losses induced by intensity, duration and the environment. 
• Don't rush the process. To truly change your physiology for performance, you have to continue to stress your body in different ways. Otherwise it gets comfortable and you no longer receive an adaptation. High intensity efforts and strength/power training are just as important as easy sessions, endurance sessions and recovery. And don't neglect skill and technique work. All of that training is for nothing if you can't hold good form under fatigue. 
  
• You have to fuel and hydrate on race day. There's no beating the system here. If you want to perform (and have some fun doing so), you need to take in carbohydrates, sodium and fluids - in proper amounts, frequently and consistently during your long distance event. And to figure out the best fueling and hydration strategy, you have to develop confidence (and the ability to digest/absorb nutrition) through training. More so, consuming carbohydrates teaches your body how to store and utilize carbohydrates more efficiently which will reduce the risk for GI issues on race day (while promoting more efficient use of carbs to delay fatigue).
  

If the majority of well-designed research clearly shows that the strategies to become a better fat burner does not show a direct correlation with improving athletic performance. So it's worth asking the question.....are you undermining your health and performance by restricting carbohydrates, performing fasted workouts and trying to complete workouts in an underfueled state?

For many athletes, the strategies applied to become a better fat burner for metabolic efficiency or to burn more fat to change body composition are nothing more than a form of underfueling - which means you are not eating enough to get the results that you desire. Yet scenarios play out all the time as athletes try to apply the weight loss methods for the non-athlete population, assuming that eating less carbs = fat burning and weight loss.

Sadly, far too many athletes are using endurance training as compensation or punishment in order to look a certain way or to justify eating patterns. You don't need to ride your bike for 3 hours in a fasted state just to "earn" a bagel. And you don't need to punish your body with a high intensity workout just because you ate a cookie. 

The methods that you are using to become a better fat burner (or to lose weight) are likely not working. I know this because I see it time and time again. Not eating adequate carbohydrates in the diet, not timing nutrition with training, not utilizing sport nutrition properly and having an unhealthy relationship with food (alongside body dissatisfaction) turns training into a method for weight loss, but it doesn't work. You are simply undermining your training, sabotaging your health and these methods have the exact opposite effect on your body composition than you are trying to achieve.

As a result, health is compromised, fitness improvements are slow to achieve (if at all) and all that training, time, energy, money and effort is for nothing come race day because the body is undernourished and overtrained. 

Fat burning is catchy, trendy and enticing. And some methods may work for improving performance in the short-term. But the long-term repercussions of not feeding your active body enough food and nutrients are concerning - from a weakened immune system, bone loss and nutrient deficiencies to gut issues, damaged endocrine, hormonal and metabolic health and psychological issues. 

With so much great research and science demonstrating a positive relationship with carbohydrates and performance, are your methods for weight loss and metabolic efficiency negatively impacting your health, performance and body composition?

Let's look into some of the reasons why fat burning is not all that it's cracked up to be. 

If this blog was helpful for you, please share, especially with your fat-burning obsessed training partners.