Carbohydrate depletion diet for endurance athletes

A carbohydrate depletion diet for endurance athletes was once popular among distance runners.

British distance runner Ron Hill was one of the first to attempt the carbohydrate depletion/loading diet. He used it in preparation for the marathon in the 1969 European Championship Marathon in Athens.

Although he was well behind as he began the final 6 miles of the 26.2-mile marathon, he eventually won the race easily. The diet did exactly what it was supposed to do.

In essence, the diet is done to ready the body for the stage of the race when glycogen is depleted. It’s at this point when most runners are hitting the proverbial wall. When everyone else began to hit the wall, Hill wasn’t. He easily passed the glycogen-depleted runners who were in front of him for most of the race.


These days, most endurance athletes load up on carbohydrates in the days leading up to a race, but leave out the depletion part. By loading up on carbohydrates they are ramping up their glycogen stores. This is as it should be. Just the same, there is a point where you can’t store more glycogen. Once your stores are maxed out, eating more pasta in the days before the race won’t increase the amount you have stored.

Ultimately, most endurance athletes have enough glycogen to get them through about the first 18-22 miles of a marathon. This of course varies depending on how many miles are spent running in the anaerobic zone. Unfortunately this is where most runners spend their time as opposed to the more sensible and glycogen-conserving aerobic, fat-burning zone.

The main reason the carbohydrate depletion diet for endurance athletes lost favor over the years is because it was just too difficult. It can also be dangerous. If done properly, the depletion segment of the diet will leave a person in a very weakened state for a couple of days. This can result in injury or illness. At the very least you will feel crappy and a million miles away from running a marathon if you’re doing the diet properly.


If you don’t follow the diet exactly, there’s no point in wasting your time doing it.

When Ron Hill implemented the diet for the marathon in the Munich Olympic Games of 1972, his timing was disrupted by the terrorist attack. The race date was changed and it threw the depletion and loading out of sequence. As a result he did not have the race he was expecting.

I did go on this diet several times back in my marathon days in the late 70’s and early 80’s. So I know exactly how it feels to go through it.


The process begins exactly seven days before your race. For this example we will assume your marathon is on a Sunday.

On the Sunday a week before your race your goal is to deplete your glycogen stores. A two hour or ninety minute run would accomplish this nicely.

carbohydrate depletion diet for endurance athletes

None of this during the depletion stage.

Once you deplete your glycogen stores, you do not replenish them. That means no more carbohydrates for you once you have done your depletion run. For the rest of Sunday, plus Monday, Tuesday, and Wednesday all you eat is fat and protein. No simple carbs or complex carbs. No bread, cereal, pasta, rice, donuts……..well you get the picture.

Your diet will be eggs, chicken, beef, fish and any other foods that provide little in the way of carbohydrates that can be converted to glycogen for fuel.

On Monday, Tuesday, and Wednesday go for a 30-45 minute run. This ensures complete carbohydrate depletion and will become more and more challenging with each passing day. By Wednesday, you will feel like death. If you have done everything right, you will have zero energy and the thought of running for 30 minutes much less a marathon will seem eminently impossible.


Begin the loading stage when you wake up on Thursday morning. Not Wednesday afternoon or at dinner on Wednesday. Thursday morning. If you begin loading to soon you screw up the depletion process and in that case, don’t bother going on the diet.

It’s almost remarkable how you can feel your energy level increase the moment you eat your oatmeal, toast, or/and hash brown potatoes on Thursday morning. It only gets better as you begin eating high quality carbohydrates Thursday, Friday, and Saturday.

Carbohydrate depletion diet for endurance athletes

Whole wheat bread is an excellent source of complex carbohydrates

If nothing else, trying this carbohydrate depletion diet for endurance athletes will once and for all educate you on just how important carbohydrates are as a source of energy.

For all those who write their books about how carbohydrates are bad for and unessential, I defy them to do the depletion stage of this diet and then run a marathon. Or for that matter, run around the block.

Going into a race devoid of glycogen stores is like getting in your car for a 100 mile road trip with a tablespoon of gas in the tank. It would be like trying to run a marathon on Thursday morning after denying yourself carbohydrates for four days.

I physically cringe when someone writes that carbohydrates are the root to all diet evil. They proclaim that it’s carbohydrates that are the major cause of obesity and poor health in general. I believe the major cause of obesity and poor health is laziness that equates to lack of fitness, and a failure to understand how everything we do, everything we consume is assimilated by our body….and this is who we become. We shouldn’t ask what are bodies are doing to us when we look in the mirror. We should ask “what are we doing to our bodies?” We are the ones in control.

If you consume more calories than you burn, your body will store it as fat for future use. That’s the message you’re sending it. It doesn’t matter if those calories come from fat, protein, or carbohydrates.

As far as this carbohydrate depletion diet for endurance athletes goes, I believe it’s worth trying at least once if you’re are hard core runner.

Just be sure to spend a lot of time in your aerobic, fat-burning zone in the first half of the marathon. If you can do that along with this diet, you should be passing a lot of people who are walking, or running very slow, in the last five or six miles of the race.

You might also enjoy this article on complex carbohydrates for endurance athletes.

Carbohydrate facts for endurance athletes

Understanding these carbohydrate facts for endurance athletes can improve race results.

It pays to place a well thought-out diet high on your priority list just as it’s important to learn the ins and outs of swimming, biking, or running.


It has been proven many times over that any diet will show more positive results if regular fitness is part of the equation. The same also holds true that you can train like a gladiator and stifle your athletic performance results if you don’t fuel your body properly.

Perhaps most of your adult life you have never given much consideration for what you were eating and have payed the price with excessive weight gain.

You have been puttering around like a “55” Ford and taking on low octane fuel that never burned properly and simply converted to fat. Once you begin to train for triathlon on a regular basis things begin to change dramatically.

Suddenly you are becoming a Ferrari that demands more attention to fueling and it is high octane all the way for best results as far as training, racing, and recovery.


Most people heard of fats, proteins, and carbohydrates and know a little about them but are not quite sure how they fit into the equation when it comes to making the most of their training diet.

They most likely have also heard of the mystical wall that appears in the late stages of a marathon on a regular basis but have no idea why it happens.

There are marathoners(and I was one of them early in my running career)who would continually run right into that wall in race after race and have no idea how to prevent it.

I am no doctor or dietitian but over the years I have done enough research and race situation experimenting to be able shed some light on the subject.

If you intend to tackle long distance events like the marathon or the Ironman Triathlon these carbohydrate facts for endurance athletes should give you something to think about.


One definition of insanity is doing the same thing over and over again and expecting a different result.

No matter if it’s running, triathlon, or any other sport that requires physical effort over an extended period of time you will not realize your best results until you grasp the role that carbohydrates and fats play in your endurance.

If you never change what is causing regular endurance melt-downs, you will continually run into the same problem and things will never improve.

Not only does it stop you from performing at your best, it also makes your race experience a lot more difficult and less enjoyable than it has to be.

I used to think that it was normal to have an energy crash late in a marathon around the 18-20 mile mark and came to expect it, but it was years later before I found out it could have been avoided.

Carbohydrate facts for endurance athletes

Adopting a diet structured for endurance will make a huge difference to your marathon results.

I simply did not know any better. Usually if I asked somebody about it they would say something like you went out too fast. Great! But how the Hell do I know what too fast is?

It all begins with the food you eat. In basic terms, the carbohydrates you eat are converted into energy. It is a misconception that in order to have more endurance you simply have to load up on more and more carbohydrates before the big race. To a point that is true, but there is a limit to the amount of carbohydrates your body will assimilate and after that it is over-kill and more is not necessarily better.

The carbohydrates we consume are converted to fuel in the form of glycogen and as a rule the average person has enough glycogen to last until about mile 20 of the marathon(hmmm). What a coincidence. At that point you have reached a state of carbohydrate depletion and your body shuts down and you are in for six miles of Hell out on the marathon course.

In a triathlon like a half-ironman and especially a full Ironman it might happen part way through the bike course or for sure out on the run course depending on how quickly you deplete your stores of glycogen.

So yes, in a way this happens when you go out too fast when the gun goes off but there is a way to figure out exactly what too fast is and how to avoid the energy melt-down.


Although the amount of glycogen we have available for energy is quite limited the same is not true of fat.

We have enough fat available for fuel to last hours longer than glycogen. So one of the major keys to improving endurance is to figure out how to burn fat as fuel instead of depleting our glycogen stores and experiencing an energy melt-down before the race is over.

When the gun sounds for the start of a marathon or the start of an Ironman Triathlon swim probably over 50% of the starting field takes off far too fast in the early stages.

What they are doing is tapping directly into their energy(glycogen)stores right from the start and are unknowingly setting themselves up for a date with the dreaded wall later on in the race.

Carbohydrate facts for endurance athletes

IM Couer d'Alene swim start

Chances are they will be shuffling along with dozens, or in many cases hundreds of others when they all meet exactly the same fate and run right into the wall at about the same point in the race as their energy is totally expended and their tanks run out of fuel.

Now go back to the same race start and lets look at the athlete who eases into the start of the race and is not getting swept up into the emotion of it all.

Believe me, whether it is a marathon or an Ironman the air is simply super-charged as everyone is anxious to go as they have trained long and hard for this day and have been resting up and their energy and anxiety levels are at their peak.

The athlete who has gone out slow is competing well within himself and is not pushing himself. When the gun sounds if will seem like he is being left so far behind by all those who are flying by him. It takes self-discipline to stay the course but it will be well worth it as the day unfolds.

Because this athlete is competing within his limits, he will be more apt to be burning fat as opposed to glycogen and therein lies the key to avoiding the dreaded invisible wall that has crushed so many dreams along the endurance race highway.

So the first thing to do is to figure out the best fats and carbohydrates to include in your diet for optimum results and just how much of each one should be eating.


Many people have the idea that fat is a bad thing and should be avoided at all costs, but that is a misconception. Fat is just as essential as carbohydrates to complete the combustion sequence that will provide the high octane fuel that will power you.

Fat is an essential ingredient in any quality diet, but Just make sure that it is a high quality choice. By high quality I mean fat derived from super-foods like extra-virgin olive oil and coconut oil. Do away with the cheaper less healthy vegetable oils and margarine. Wherever you can use olive oil and coconut oil in their place in your everyday cooking and favorite recipes.

I found that about 5-6 tablespoons of coconut oil a day used in meal preparation worked best when I was in dedicated triathlon training. I actually lost weight when I used coconut oil on a regular basis because coconut oil tends to speed up the metabolism.
Carbohydrate facts for endurance athletes
Other great options are chicken, turkey and sardines which are high in Omega-3 fatty acids. Limited amounts of dairy fats are okay as well, especially if they are raw and not pasteurized or homogenized. Organic dairy products are a better dairy choice as they have retained much more of their nutritional value.

Despite all the bad press that eggs have received for decades they have now become recognized as a healthy food. The yolk is a great source of lecithin, vitamin A, vitamin C, and many other nutrients. However they are best when not over-cooked. Poaching or boiling or perhaps raw in a smoothie are the best alternatives in order to retain the most in nutritional value.

I would view wheat germ oil, rice germ oil, and peanut oil as secondary choices. I always had natural peanut butter around and always make sure it does not have icing sugar or anything else added. Always read the label. Under ingredients all it should say is peanuts You will know when you have the right peanut butter when the oil has settled to the top and you have to mix it before you use it.


All carbohydrates are not created equal.

Carbohydrates basically fall into two categories called “simple” and “complex.”

If you just remember these rules of thumb when it comes to telling the difference from a simple carbohydrate and a complex carbohydrate you will pretty much have it figured out.

It it tastes really good and you almost guilty eating it than most likely it is a simple carbohydrate. If it is called “chocolate” anything then it is most likely a simple carbohydrate. It it comes at the end of a meal and has ice cream piled on top it is pretty much a 100% simple carbohydrate.

Carbohydrate facts for endurance athletes  ice cream

For "after" the race

If it is the last thing you see on the shelves beside you as you check out of a super-market, it’s most likely a simple carbohydrate. They are put there for a reason. They are called “impulse sales” as they trigger the sugar mechanism deep inside us and it calls out “just one Oh Henry won’t hurt.

The problem with simple carbohydrates is that they rush the sugar into our systems and create a sugar imbalance, and sometimes a “sugar crash” that can sap energy almost instantly.

I would not be exaggerating if I said that at the peak of my endurance career when I was having by far my best results in marathons and the ironman, that my diet consisted of almost 70% complex carbohydrates. The other 30% of my diet was divided between protein and fat.

However a good average to shoot for is 40% Carbohydrates, 40% protein, and 30% fat.

Yes sir, my meals revolved around oatmeal, whole wheat bread, brown rice, potatoes, and pasta. I didn’t really care if I had oatmeal every morning and pasta every night for weeks on end because to me it was simply fuel as I was training at a high intensity.

No matter how much I ate my weight was stable at between 148-152 pounds for years on end.

Because these carbohydrates are “complex” they take longer for the body to assimilate and do not rush into your bloodstream right away in the form of sugar. They actually provide a fuel that is burned in the fire of clean-burning fat.

The very same fats that I mentioned above.

In this day and age you have to practice caution when overloading your body with complex carbohydrates.

Agricultural growing practices have changed drastically in the past 3 or 4 decades. In order to keep up with market demand shortcuts are often take when it comes to growing the food we depend on.
Carbohydrate facts for endurance athletes

Most whole wheat these days comes from grain that has been altered in one way or another to speed growth.

I figured that out a long time ago and believe it or not, I actually used to spend 4 hours about once every three weeks making my own whole wheat bread from scratch with organic whole wheat flour.

That also meant I knew “exactly” what was added to my bread. In my case it was olive oil, molasses, honey, and seeds instead of poor fat and sugar choices.

It’s also wise to avoid white rice and white bread as they have most of the nutrients removed long before they ever get to your kitchen.

I love potatoes and just for myself I used to buy 20 pound bags when I was training like a gladiator. I soon discovered that potatoes are almost the purest form of carbohydrate there is and must be balanced with a protein in order to slow their absorption into the blood-stream.

I remember a pro triathlete once saying to me, “if I had my way I would haul about 5 baked potatoes with me in an Ironman.” So obviously he also realized the potential of this particular carbohydrate choice.

I used to do a long workout and then treat myself to about 4 large potatoes cut up and steamed with some onion and spices and often about an hour later had severe energy crashes until I figured out that I had to eat something else with the potatoes in order to slow their absorption rate.

In subsequent meals I topped the potatoes with cottage cheese or included eggs with the meal and the energy crashes stopped.

So it follows then, that if you are on a strict training diet and want to treat yourself to the occasional ice cream cone or Mars Bar, eat a cup of cottage cheese before you do and this will help balance the flow of sugar into your system.


So now we come down to how you put all this together to work for you when you are standing at the start line of the big race.

As I said earlier, it’s easy for someone to say you are going out to fast but nobody ever tells you how to determine what too fast is for you.

So here is a basic look at how you can figure it out and probably the best tool to help you get the most out of burning fat instead of glycogen burning is a heart-rate-monitor.


Training and racing within your fat-burning zone(anaerobic zone) is the key to endurance race success. If you take your age and subtract it from 180, you will have a starting point.

So for examples sake, say you are 40-years-old. You will come up with a figure of 140 once you subtract 40 from 180. Go back ten beats from there to 130. So basically your fat-burning range is 130-140 and that is the heart-beat range where you want to do the majority of your training.

When you go for a run, simply check your heart-rate monitor and be sure you are staying in your fat-burning zone of 130-140.

It is always best to warm up first with a 5-minute brisk walk or easy run that is below 130 beats, so say you warm up at 110-125 beats before settling into your run at your fat-burning pace of 130-140.

During your training it’s important to avoid spikes in your heart-rate whenever possible. It might mean walking up steep hills at first so your heart-rate does not spike up 15 or 20 beats.

It might also mean that you will be running very slow at times and even walking until your heart-rate settles back down, but that is normal. This can take lots of patience, but it is well worth it.

Over the days, weeks and months as you train within that zone you will begin to run faster and further while staying in exactly the same fat-burning range. Congratulations! You are getting fitter.

The beauty of a heart-rate monitor is that it will not let you do more than you are capable of if you follow it to the letter. It you go uphill your heart-rate will rise, and if you go down-hill it will most likely fall as it takes less energy to go downhill and you slow down or speed up according to what your monitor is telling you.

Carbohydrate facts for endurance athletes and heart rate monitor

Heart-rate monitor

So basically, what you are accomplishing over time by burning fat for fuel in training is conditioning yourself to perform within your ability. So one day you will find yourself running faster and further and yet you are not working any harder than the early days when progress seemed so slow. You are still in the very same 130-140 heart-range.

So when you find yourself at the start line of a marathon for instance, you fire up your heart-rate monitor and when the gun sounds you do exactly what you did in all those months of training for this day.

Usually you can take the heart-rate up a little on race-day and you will still be aerobic and in the fat-burning zone and in this example 140-150 as opposed to 130-140 would most likely be about perfect.

A lot depends on your age and if you are in your 20’s it would be best to stick to your predetermined aerobic range and not change if upward for the race. If you do possibly just 5 beats, but no more.

If you are doing everything right and letting your heart-rate monitor guide you, you will slow down on the inclines on the course and speed up on the downhills. During this time your heart-rate should be in your per-determined aerobic, fat-burning zone.

In the process you are preserving your valuable glycogen stores for later in the race. So when every one who went blowing by you at the race start is walking or running very slowly at the 20-mile mark you will feel great and have lots left.

As you get into the late stages of the race you can most likely go for it and even race above your aerobic heart-rate because you have plenty left and it’s always a thrill to be passing dozens or even hundreds of others and have tons of fuel left in the tank.

Because you have not expended all your glycogen and have been burning fat for fuel all day, you still have lots of glycogen to use at the end and do not have to worry about hitting the wall any more as the race is almost over.


So there you have it. Those are some important Carbohydrate facts for endurance athletes.

It all begins with creating a proper diet and eating the right combination of fats and carbohydrates.

It also means choosing the very best fats and carbohydrates.

Once you have the diet figured out you take the next step of training and racing within your ability and at all costs avoid expending excess energy, especially early on in a race as there is no recovering lost energy during race day as it is gone forever.

I believe a heart-monitor is the best tool to help you achieve your goal and perform at your absolute best. As the years go by you may get a feel for the perfect pace for your training and racing, but sometimes is a skill not everyone can master.

Using a heart-rate monitor along with taking a few of these tips about carbohydrate facts for endurance athletes will go a long way to helping you achieve your goals.

I talk about setting up this heart-rate training method more extensively in my triathlon books and also discuss the diet components of fats and carbohydrates at more length and share information on how I make the most of coconut oil and olive oil for best results.

I have written five books and they have helped many people realize their triathlon goals and dreams. Once people buy into what I have to share in my books they realize that it is within their grasp to do something spectacular.

I really believe that people are capable of so much and they just don’t realize it and in many cases have given up on themselves. The books I have written are as much about inspiration and motivation as they are about swimming, biking, and running.

If you are just starting out in triathlon than Triathlete In Transition is the perfect book for you.

If you are a marathoner and becoming a triathlete is on your mind than you will get learn so much and be inspired and motivated by Ironstruck…The Ironman Triathlon Journey and Ironstruck? 500 Ironman Triathlon Questions and Answers.

In all three of my triathlon specific books I discuss at length the above topics concerning heart-rate monitor training, coconut oil, extra-virgin olive oil and the best over-all diet and foods in order for a triathlete to get the most out of their triathlon experience.

For more information on being a more successful triathlete or Ironman be sure to have a look at the books I have written that have helped many triathletes around the world realize their Ironman and triathlon dreams and goals.

You can visit my ironstruck book store and find the perfect book for the new or experienced triathlete doing their very first try a tri triathlon or the Ironman.