After six weeks of training, both groups had improved a similar amount on a minute time trial. Another study albeit of lower quality, as it used only a handful of untrained men as subjects by Nybo et al. confirmed the findings of Van Proeyen et al.

paper also increased their fat burning abilities more than the carbo-loaded subjects; furthermore, they also increased their stores of muscular glycogen. While you might suspect that these changes would have enabled these untrained men to lose more weigh, there was no difference in the weight lost between the men who trained after an overnight fast and the men who did not.

So, it appears that doing some training in a glycogen-depleted state can be of benefit to marathon runners. But there are some important considerations to be made. First, keep in mind that the fasted-training subjects in the Van Proeyen and Nybo studies did not get in better shape than the carbo-loaded subjects!

Their improvement from training was identical; the only differences were related to fat metabolism. Second, the ability to run a given pace with less reliance on glycogen does not necessarily mean your aerobic endurance has improved i. your oxygen consumption at the given pace.

Finally, there is a very practical reason to practice consuming carbs before and during a long run: you have to be able to do it when you race! It definitely takes training to get used to eight or twelve ounces of sports drink sloshing around in your stomach after ten miles of running, and you definitely want to make sure you can tolerate your pre-race meal.

Setting aside some non-critical runs to be done right away in the morning i. without breakfast appears to be a good way to increase your ability to directly burn fat while running.

Long runs on an empty stomach or fully fueled. How to practice your nutrition strategy. How to teach yourself to burn fat on your long runs.

Interview with marathoner Nate Jenkins. Your team of expert coaches and fellow runners dedicated to helping you train smarter, stay healthy and run faster. We love running and want to spread our expertise and passion to inspire, motivate, and help you achieve your running goals.

Bourne, P. PLoS Computational Biology , 6 10 , e Coyle, E. Journal of Applied Physiology , 61 1 , Painelli, V. Nutrition Journal , 9 Van Proeyen, K.

Journal of Applied Physiology , , Nybo, L. Acta Physiologica , 2 , When the temperature outside heats up, hydration becomes a big obstacle for distance runners.

The running community in Minneapolis is indignant about malfunctioning drinking fountains. In fact, the nutritional component can be as, if.

Glad to see you site some research on a topic that I have grappled with for many years. I came across an article in an old issue of Marathon and Beyond that made the same claim: fasting prior to running increased your ability to burn fat.

According to the article two hours was minimum fast time, overnight was optimum. I experimented on my long runs with fasting and recorded my fastest race times when I followed the fasting concept. But what they also mentioned in that article that may in fact be the key to making this a practical way to train and even race was that calories taken in after exercise began do not cause the GI index to increase.

Thus fasting prior to starting your run and then fueling throughout your effort is really the best way to approach the long run. Do you have any insight or studies that further support this concept? Honestly it worked wonders back when I was faithful to the fasting and I just recently returned to this idea last month.

I have completed two long runs without bonking OR gastric distress post run after returning to this method. Thanks for sharing, David. David, they may have been referring to the fact that during exercise insulin is supressed, therefore the concept of glycemic index has no meaning.

Skeletal muscles take up glucose readily via an insulin independent mechanism during exercise. I am a big believer in the value of training in a fasted state.

If you take in carbs, sugar drinks during the long run, you are not in a fasted state. Thanks for sharing your success with training in a fasted state, Greg. Always nice for others to hear stories of it working because training in a fastest state sucks! Losing weight is always calories in vs.

i dont think u really do understand what he meant that no weight was lost, he said no weight was lost not fat, meaning they gained muscle not to mention they added some extra glycogen to there muscles, I highly doubt that glycogen got stored as fat as active as they r , theres a reason itz in big bold letters!!!

i know that this post is old but i didnt want the posts to mislead ppl. This was a time when I was trying to drop weight and build my base. They were very difficult, I felt horrible the last few miles of every run. Once I started marathon training I supplemented normally.

My long runs went great. I ran only slower than GMP up to 22 miles. My long run pacing strategy was high for other reasons but the point is that pace was easy to hit and I never bonked.

Taking a gel around miles can help prevent that feeling and improve race performance. Race-day nutrition can be a bit of a balancing act, but you never need to over-complicate it. Before the race, try eating solid food rather than a gel, so that your stomach has something substantial in it before the gun goes off.

The food should be simple and contain sugars that can be burned easily while running, such as toast with jelly or oatmeal. During the marathon or ultramarathon , take a gel every 45 minute to 1 hour, especially in the early stages, before your stomach has a chance to become upset.

If later in the race, you feel that your stomach is too tumultuous to take in more gel, perhaps stop at an aid station and drink an electrolyte drink such as Gatorade.

Those drinks will still contain calories to give you energy, but they won't be as heavy as a gel. Choosing an energy gel is a personal decision. Each is different: some contain caffeine, some do not; some tend to be less viscous while others are thicker; etc. Go to a local run specialty store to ask about the specifics of each different type of gel and pick a few to test on training runs.

Choose the gel that feels most natural to you. If you find that the texture of gels bothers you, there are many alternatives such as energy gummies or waffles that typically have the same effect as gels.

Whichever form of race-day nutrition you use, make sure you practice using it during training runs so that your stomach becomes accustomed to the taste and feel of that particular form of nutrition.

Good luck in your next running endeavor!

Add sweet potatoes to a meal or two. Have a quinoa dish one night. Maybe breakfast on some oatmeal and a banana instead of rushing out the door every morning. Be conscious that you are eating carbs, but you don't have to over-do it.

On the morning of the race, I recommend having a breakfast of easily digestible carbs such as toast with jelly and a banana. Even if you get an upset stomach from nerves, it is important to have something in your system on race day. Finally, during the race make sure that you take nutrition early and often to prevent glycogen depletion later.

There are many good forms of race-day nutrition such as gu's, gummies, bars and fruit. So, practice nutrition intake during long runs and find what works best for you. There are some runners, though, that no matter what they do nutritionally they still bonk in the late stages of every marathon.

For those runners, there is a training method called "Glycogen Depletion Training" that basically teaches your body to burn fat more efficiently, so when your body runs out of glycogen it can still perform.

If you are interested in this method, I recommend pursuing it very carefully. To train in a glycogen depleted state, a runner does a run in the morning without taking in any carbohydrates since dinner the night before. Two weeks later my legs are dead, and I still feel wiped out, even though the muscle soreness was gone within a couple of days.

Should I resume your training program, or is there some other approach to get me ready for Milwaukee? You got through one marathon undertrained, so you probably can get through another without following any program precisely.

If your legs are dead, that signals that you have not replenished your normal levels of glycogen, the fuel for our muscles.

Although most runners replenish glycogen within a week, for some it may take a month. In short: running out of glycogen is the end of every high performance effort. That is why you want to know exactly how much glycogen is available in an individual athlete, instead of having some rough estimates.

INSCYD is the first and only tool that provides you this information. Now you know the disastrous effects of running out of glycogen, you probably wonder how you can maintain glycogen stores during exercise. The most obvious one is to decrease exercise intensity.

This will decrease carbohydrate combustion, increase fat combustion, and as a result: maintain glycogen stores for a longer period of time.

Examples are energy drinks, bars and gels. Long-term, you can also maintain glycogen stores longer by increasing fitness level. As mentioned, a higher fitness level will increase the maximal amount of glycogen stored per kilo muscle mass. When an increase in fitness level comes from an increase in aerobic power, you will also rely less on carb combustion and more on fat combustion.

By playing around with the INSCYD glycogen availability calculator, you can see how changes in fitness level and aerobic power have an effect on how long an individual can maintain glycogen stores during exercise. Experiencing low glycogen stores is of course not a big problem once you crossed the finish line.

In fact, in most races or intense training sessions, this is inevitable. You should however make sure you replenish muscle glycogen stores afterwards, to make sure you have enough energy for the next race or training session. Fill in the form to receive an email in which you learn how you can use glycogen depletion and replenishment to create a training camp program.

Additionally, you can schedule a free consultation with us in your own language or write to us to discover how we can help you transform your training program with personalized glycogen insights. It goes beyond the scope of this blog to talk about the exact nutritional strategies to replenish glycogen as fast as possible.

You can get more information about nutrition and glycogen via the form. It is however good to know that it will take a minimum of 48 hours to fully replenish glycogen stores once they are depleted. We talked about all the important aspects of muscle glycogen during exercise and hopefully gave you a better overall idea of how glycogen stores change during exercise.

Calculate how much glycogen your athletes have in their active muscles. Learn how much they burn at any exercise intensity. Create a nutrition plan to make sure to never run out of glycogen again.

As a coach or lab professional, you can gain valuable insights into glycogen by scheduling a free consultation with the INSCYD team in your own language.

Unlock the full potential of your athletes and elevate their performance. Create highly personalized training programs with lab-level performance insights anywhere anytime to analyze, optimize and improve performance faster and save cost. Skip to content.

Launch App. Muscle Glycogen and Exercise: all you need to know. Download full article in PDF. WHAT IS GLYCOGEN. HOW MUCH GLYCOGEN IS STORED IN THE BODY. Example of how the total glycogen content differs per athlete. Glycogen: a core protein surrounded by thousands of glucose branches.

HOW MUCH GLYCOGEN IS STORED IN THE ACTIVE MUSCLE. Example of how the available glycogen content differs per sport. Body composition. Since glycogen is stored in the muscle, the more muscle mass you have, the more glycogen you can store.

Type of exercise. Certain sports require more muscles to be active than others.