Low carbohydrate Ironman triathlete diet

I really don’t believe there is any good argument in support of adopting a low carbohydrate Ironman triathlete diet if you want to perform at your best.

These days there are dozens of books and internet articles slamming carbohydrates and in it’s stead, promoting low carbohydrate diets that are comprised mainly of protein and fat.

The Atkins diet was one of the earlier diets slanted in this direction and opened the door to people eating all the bacon, eggs, and steak they could handle…..as long as there were no hash-browns with eggs or baked potatoes with the steak.

low carbohydrate diet for ironman triathletes

Eat all the eggs you want on the Atkins or 4-Hour Body diets.


It should be noted that the Atkins diet did allow carbohydrates to be eased into the diet after two weeks, and increased over time.

The 4-hour Body by Timothy Ferris is also a high protein, high fat, low carbohydrate diet. However you are allowed one cheat day a week where you can eat as much of your favorite foods as you want.

Wheat Belly by William Davis, M.D. is basically the Atkins Diet. The only difference is that Wheat Belly does not allow cured meat, so that means bacon is out but bring on the eggs.

It is not just lose the wheat, lose the weight as the cover of the book proclaims. It is also loose the potatoes and lose the rice and any other carbohydrates you might enjoy.

Basically, all three of these diets are based on the same principle of high protein and low carbohydrate any way you look at it.

It’s not a mystery. If a person truly wants to lose weight, they will accomplish that on any of these three diets.

However if a person wants to do the Ironman Triathlon, they will most likely call it a day shortly after the 2.4-mile swim as they smash head-first into the wall while scrambling to get their wetsuit stripped.

What Dr. Davis promises removing wheat will do for your general well being:

....Improve athletic performance
....Improve mood
....Reduce mood swings
....Improve concentration
....Improve sleep
....Increase energy
....Slow skin aging
....Improve coordination

Improving athletic performance is sort of a sweeping statement as I don’t believe all athletes will see improved performance on high protein, low carbohydrate diets. Weight lifters would most likely benefit the most from this type of diet as far as athletes go.

Rather than just believe what a book says and what critics say, I test these diets out for myself so I can write a more informative article.

I tried out the Atkins Diet and must say that I enjoyed the three or four eggs and six slices of bacon for breakfast but at the same time really missed my oatmeal, hash-browns, toast, and blueberry pancakes.

After several weeks on the Atkins diet I entered a 10k race. The gun went off and within 200 meters I knew I was in trouble and in for a tough race. My normal 38-minute time on the same course the year before became a 43-minute time. I had no energy and for the first time in my life considered dropping out of a 10k race and I ran about 100 of them.

I tried The 4-Hour Body diet as well to see if the weight loss and muscle gain that was promised actually happened if I followed the diet to the letter. Some weight lifting and strength exercises were also incorporated into the plan.

True to form I reached my lowest weight ever and gained much more muscle definition after about six weeks. This was including a cheat day every Saturday when I could eat as much of anything that I wanted to.

low carbohydrate diet for ironman triathletes

My favorite food on the 4-Hour Body diet eat what you want cheat day.A stack of blueberry pancakes.


Usually my cheat day included a stack of blueberry pancakes smothered in butter and syrup, three bowls of ice-cream, four jelly donuts, some chocolate bars and many pieces of toast with jam.

I would gain back three pounds on cheat day and loose it again by Tuesday and then start losing in over-all weight again.

The important thing to note here is that my one-hour run on Sunday went much better than a one-hour run on Thursday or Friday.

Obviously, having carbohydrates in your system to increase glycogen stores is crucial for optimum athletic endurance performance.

It seems to me that if you go into an endurance race like the Ironman coming off of weeks of a high protein, high fat, low carbohydrate diet your glycogen is already depleted before the start gun goes off and you will soon be in trouble.

I’m no doctor, but from my own experience I don’t believe any low carbohydrate diet is beneficial for endurance athletes.

A low carbohydrate diet will actually deplete your glycogen stores. This in turn will cause dehydration and the weight you lose may not be all it appears to be. The weight you lose on high protein diets is often fluid loss caused by this dehydration. So in reality, it’s not really fat loss. This would most likely be especially true in the early weeks of the diet.

Without glycogen stores it takes no time at all to become fatigued. Without glycogen in your muscles there isn’t much enthusiasm to exercise or even move, so how can one hope to finish an Ironman on a low carbohydrate diet?

Carbohydrates such as fruits, vegetables, legumes, whole grain breads and pastas, and brown rice are excellent fuel sources for endurance athletes. However the amount of these you eat should be dictated by the amount you exercise(or in the case of an Ironman triathlete…how much you train).

If you life a sedentary life-style and seldom exercise, excessive carbohydrates will most likely lead to weight gain, but if you are training religiously for an Ironman it’s possible to eat large amounts of carbohydrates and never gain a pound.

If the amount of calories you take in is more than the amount of calories you burn, you will most likely gain weight. It’s not a complicated formula.

The best diet book I ever came across is EAT TO WIN by Dr. Robert Haas. It was written sometime in the mid-eighties and I don’t even know if it’s still in print.

It was a high carbohydrate diet that fly’s in the face of all these high protein diets that are being touted all over the place.

low carbohydrate diet for ironman triathletes

Add some honey and you have my favorite fuel that I took along on the Ironman 112-mile bike back in the racing days.


On the Eat To Win Diet I was eating up to 70% carbohydrates on a daily basis. The other 30% was split between quality protein and fats.

I ate copious amounts of potatoes, pasta, whole grain bread I made myself, and brown rice.

I raced at 150 pounds and my weight hardly varied from year to year. I had my best Ironman result ever on this diet plan.

Back in 1987-88 when I went for a morning training swim at the local pool the Aquabelles would often be training in the adjacent pool for the upcoming 1988 Seoul Olympic Summer Games.

One day I was talking to their coach and I asked her what diet they were on and she said…the EAT TO WIN Diet.

I knew then I was on the right track. The duet of Michelle Cameron and Caroline Waldo who were training in the pool beside me won the gold medal in Seoul. I doubt very much that they would have had the necessary energy for their long, energy-sapping routines on a high protein, low carbohydrate diet.

It’s very true that carbohydrates burned in the fire of quality fat generates the fuel for endurance athletes.

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2 thoughts on “Low carbohydrate Ironman triathlete diet

  1. I see worldview after worldview posted by people that supposedly try a “low-carb” diet and report that it just doesn’t work for them. Every last one that I have seen suffers from one or more fatal flaws and I have to add that so many of the failures I see are from people that truly believe they know what healthy eating means, and it includes a lot of fruit and vegetables and whole grains. If you are one of these people, you are surely healthier than the average, but your preconceptions are going to prevent you from experiencing the benefits that a ketogenic diet can bestow upon you.

    If you think that a ketogenic diet is a high-protein diet (looking at you, ironstruck), you are wrong and should rethink what you did and actually do a ketogenic diet before you bash it. Get a blood meter and actually test your ketone levels before you give us advice regarding how ketone levels affect your performance.

    If you think you can follow a ketogenic diet for performance and you think cheats (even those supposedly healthy “whole” grains or yams) are okay in moderation (oh is that term a misnomer), you are wrong and should not be commenting on ketogenic diets.

    I know that there are many perfectly intelligent, conscientious people that have some of these misconceptions and that is why every person has to figure out what works for him or herself. I merely hope to see truth rather than misconceptions as much as possible in n=1 reports.

    I personally will be training and racing for Lake Placid 2014 in an actual ketogenic state and I know it’s going to be great, based on my previous experience with a high-fat diet. I’m no pro triathlete by any means but I do hope to beat my family and friends without choking down gels every 20 minutes. 🙂 The record will tell the tale and good luck to each one of us!

    • Thank you for your comment. It would be fun to follow your results in IM Lake Placid 2014, but you omitted your name from your comment. Hmmmmmmm

      I don’t as a rule comment on diets(or bash them as you say)unless I have tried them myself. Despite all the controversy surrounding the Atkins diet and his assertions about the advantages of being in the Ketogenic State I went ahead and tried it.

      As I mentioned in my article, I suffered drastic energy loss and although a low-carb, high-fat, high-protein diet might be great for weight-loss, I was never convinced it was ideal for endurance athletes.

      It’s pretty much common knowledge that there is a severe drop-off in energy in the early weeks of a low-carb, high protein diets if making the switch from high levels of carbohydrates, as it can take anywhere from 4-12 weeks for the body to adapt to the ketogenic state.

      During the Second World War there was an experiment performed examining the practicality of pemmican (a mixture of dried meat and fat) as a light-weight emergency ration for soldiers. This experiment involved abruptly switching soldiers in winter training in the Canadian Arctic from standard carbohydrate-containing rations to pemmican. This study only lasted 3 days, as the soldiers rapidly became unable to complete their assigned tasks, which included pulling loaded sleds 25-miles per day through deep snow.

      Personally, I like to enjoy what I eat and overly-restrictive diets are not for me.

      I agree 100% that an endurance athletes should learn to burn fat for fuel and in the process conserve glycogen for when it is most needed(for instance at the end of a marathon or Ironman when everyone is hitting the wall).

      However this can be accomplished by learning the proper use of a heart-rate monitor that will keep you in the fat-burning zone through-out the bulk of your training. This in turn teaches your body to burn fat for fuel and results in increased endurance and far better performances in Marathon and Ironman Triathlon events.

      This result can be attained while eating 65-80% complex carbs, and the other 20-35% quality proteins and fats as I was doing on a daily basis and does not require one to be in a restrictive ketogenic state.

      You can also say goodbye to intense weight training, track intervals, or just about any activity that would be consider “tempo”, “threshold”, or “intervals” if you’re on a strict low carbohydrate diet.

      As these were always an integral part of my training, the diet you suggest simply would not work for me.

      Most of all though, I prefer to follow the diet regimen of the Kenyans, the greatest endurance runners in the world who have produced a staggering 40% of winners of all major international middle- and long-distance running competitions between 1987-1997. The total mean daily carbohydrate intake of the adolescent runners was 476 grams (8.7 g/kg, 71% of total calories). Total intake of protein and fat was 88 and 45 grams, respectively.

      The most recent study to look at the dietary habits of Kenyan runners also involved Kilenjin athletes. Researchers observed them during a training camp in the North Rift Valley, and found they ate three meals and 2 snacks daily. The staple foods were bread, boiled rice, boiled potatoes, porridge, cabbage, kidney beans, and a thick maize meal paste known as ugali. Meat (mainly beef) was served at the training camp 4 times per week, although the athletes were able to access more meat when at home. Generous amounts of tea (with milk) were consumed throughout the day.

      Hmmm…….. bread, rice, potatoes, porridge, and beans. Sounds a lot like the Eat to Win Diet I was on that produced my best 10k, marathon, and Ironman Triathlon results ever.

      Best of luck in Ironman Placid 2014. I hope you realize all your Ironman dreams and goals.

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