Eating Strategy Experiment

Please note that my comments below are my present understanding of the various processes that come into play and are not claimed to be absolutely accurate or authorative. It is an experiment and I am reflecting my thoughts about the issue here. I am also experimenting with various refueling strategies in this entry and am providing my rational for these. I will most likely adapt these over time as I gain a better understanding of the process, am able to access additional research and test the various strategies, eating plans and ideas. I will continue to update my eating strategy so revisit this blog from time to time. 

Your comments are welcome!

I am at the stage in my training that I feel the decline in performance during my long run. If I split the distance into two, running each at different times during the same 12 hour period my performance is maintained. This I ascribe, after some research, to basic running physiology, which simply means that my energy stores become somewhat depleted during my long run.

Example of my weekly training:

• Mon: 10km @ 10km/h pace with 6.5kg weight,
• Tue: 7km @ 8.2km/h pace with 6.5kg weight,
• Wed: 10km @ 10km/h pace with 6.5kg weight,
• Thu: 7km @ 8.2km/h pace with 6.5kg weight,
• Fri: 26km @ 8.35km/h pace with 6.5kg weight,
• Sat: REST, 
• Sun: 7km @ 8.2km/h pace with 6.5kg weight,

The truth is I have done this intentionally. I decided to use the MdS preparation to challenge my own previous knowledge, to experiment again and to find those elements in training, nutrition and strategy that really work.

I therefore went back to the present research to understand the physiological process at work during my running and in specific my long run. My understanding of this process is the following:

1. When we ingest ‘food’ it is broken down into sugars which are absorbed into our bloodstream in the form of glucose, 
2. The hormone Insulin is released by our pancreas and moves the sugar from the bloodstream into cells where it is used as a source of energy, 
3. The glucose serves as an immediate source of energy, 
4. If there is excess glucose (more than what the cells need as an energy source) it is stored in the liver and muscle tissue as glycogen, 
5. If during a period of activity, the energy source (glucose) in the bloodstream falls below a pre-determined level, the glycogen is released back into the bloodstream for use, and
6. If all energy needs are met, the excess glycogen is stored as fat.

The primary questions, therefore, are how much glucose reserves are readily available at any given time, and how much energy will I consume during a specific activity. The aim of answering these two questions is to establish a strategy through which to ensure that energy reserves are easily available for use.

How much glucose reserves are readily available at any given time?

The research seems to indicate that the body is allowed to burn the easily accessible energy reserves (glucose) in the bloodstream up to a depletion point of around 50%. At this point the body switches over to burning fat reserves as a source of energy. For most runners this depletion point is reached at around the 30km mark (or somewhere between 2 ½ and 3 ½ hours). As an average we will work on a 3 hour timeline. Sport nutritionists, therefore, recommend a carbohydrate intake every 45 minutes, which translates to less than 12.5% blood glucose depletion. Through constant replenishment, the reserve does not get depleted and exercise can be sustained indefinitely (in theory).

It is noted that there is a fair level of consensus that weather plays an important role. In warmer weather energy usage is accelerated, which means that refueling should happen more regularly. The suggestion is that during normal conditions refueling should take place every 30 minutes, and during warmer weather more frequently.

There is also the issue of how long it takes from the point of ingestion until the energy reserve is available in the bloodstream. The recommendation that a carbohydrate rich meal is to be ingested 2 to 4 hours before the race may hold the answer.

The following is a rough guide to the time it takes various food types to become available in the bloodstream as an energy source after ingestion:

Food Type	Digestion Rate
Sugar (Sweets)	Immediate
Fruits	Immediate
Carbohydrates	1 to 2 hours
Proteins	4 hours
Fat	6 to 8 hours

This conversion timeline together with research done in the 1960’s and 70’s gave rise to the commonly held belief that ‘carbohydrate loading’ is the most beneficial means of replenishing and maintaining energy levels during exercise.  It seems obvious that a carbohydrate rich meal 2 to 4 hours prior to exercise ensures that energy reserves are at optimal level from the start. With this strategy, maintenance is vital in the sense that an attempt must be made to maintain the blood glucose level at an optimal (undepleted) level.

It is furthermore worthwhile to note that every gram of protein and carbohydrate contains in the region of 16.7 kilojoules, and a gram of fat contains 37.7 kilojoules. Looking back at my most recent training log, it seems as if I consume about 100 calories per kilometre or put another way, around 884 calories per hour, based upon my average overall run time of 8,84km/h. This rate of energy consumption is not standard and differs based upon gender, age, weight and running speed, so has to be specifically calculated.

For me, however, starting from an optimal, fully fuelled, position I will burn about 1761kJ within the first 30 minutes of my run (842/2 x 4.184), and continue to do so throughout. My aim should therefore be to consume 1761kJ per 30 minutes or in my case every 4.3 km’s. As sugars are immediate it might cause a spike in glucose levels with possible complications of its own, proteins and fats may take too long to enter the bloodstream. At first glance this seems to point towards carbohydrates as the food source of choice.

One option proposed is to stock up two to four hours before the run with 400 to 800 carbohydrate calories, and to refuel during the run by taking in 200ml water per 20 minutes, and about 100 calories every 30 minutes (Bean 2006). This plan means that I would start the race with around 3280kJ of energy available from the outset. I would, furthermore, add to this an additional 418kJ of energy every 30 minutes. My energy input during a 3 hour run (at 8.6km/h - 26km’s) would come to 5788kJ’s while my energy output would be in the order of 10350kJ’s. The energy shortfall of 4562kJ’s (1090 calories) must be extracted from existing blood sugar levels, liver and fat stores.

Here is the strategy I used for my experimental run:

1. I ate 800 carbohydrate calories 2 hours before my run, 
2. I took 2,0 liters of water on the run to consume over the entire period, and
3. I consumed a GU energy gel at the start, and one after every 30 minutes of the run.

My Personal Experience:

My use and review of these supplements has to be understood within the context of my present diet. In September 2011 I decided to change my diet to the following:

(1)    No starches,

(2)    No sugar,

(3)    High Protein, and 

(4)    Water only.

I effectively cut carbohydrates and sugars from my diet. At the same time I started to exercise, building my routine up slowly from inactivity (due to a previous injury that resulted in an inactive lifestyle for close to two years), to its present level of 67km’s (38 miles) per week with added weight. During this time I lost 23kg’s, and although I removed both carbohydrates and sugar from my diet had no excessive fatigue or noticeable drawbacks. I recover quickly after a run, am injury free for the most part, and continue to increase my exercise intensity.

My blood pressure is normal at 120/79, resting heart rate is 55bpm and my maximum heart rate increases to 165 bpm at a 2:40/km pace. A recent ECG provided no indication of any underlying cardiac problems, cholesterol is normal and in general I am healthy although my diet is limited to high protein such as, eggs, fish, nuts, and red-meat (± 350 to 400g per day in total) and around 2-3 litres of water.   

I don’t eat breakfast but eat between 30 and 60g of nuts at 10:00am, some dried meat (30 to 60g) at around 12:00 and a dinner that is on occasion made more interesting by adding a tomato, some lettuce or mushrooms. (It is in reality more tasty and interesting than it sounds). Effectively I consume a maximum of 2000kJ’s per day between the time that I get up in the morning until I go for my run. It is obvious that the majority of my running energy does not come from my energy intake but from fat reserves, resulting in my intentional weight loss.

It is clear that once my weight reaches my target of 78kg’s (I am at 82.5kg’s at present) that I will have to increase my energy input to ensure that sufficient reserves are available to sustain my activity. It is for this reason that I decided to experiment with gel based energy sources.

Product

I used the GU Energy Gels which are made up out of carbohydrates and electrolytes. The idea of a carbohydrate energy source is in line with the present focus on carbo-loading that is suggested by the majority of sport nutritionists. It made sense to me that carbohydrates as a source of energy can be timed, is well researched and, according to conventional knowledge, is the energy source of choice.   

It is worthwhile noting that not all nutritionists agree with this, but I discuss this further on.

Taste

I tried three different flavours, Chocolate, Lime, and Strawberry. The taste was generally pleasant although very intense. I had my wife taste the same flavors, her experience was much the same but she described the taste as less intense. I ascribe this intensity difference to the fact that I have excluded sugar from my diet for the past six months. The intensity level of the sweetness of the product dominated the taste in my mouth. It took me more than 5 minutes to get the first gel down.

During my run I consumed each sachet in about 30 to 40 seconds at the 30 minute intervals. The taste was so intense that I felt nauseas. Again, I think this had less to do with the product and more to do with the sudden dietary change I was inflicting on my body.      

Effect

I experienced no noticeable effect after taking the gel supplements throughout my long run. I still had, as before, a difficult patch at between 17 & 18 km’s (which always seems to be on the same uphill) and ended feeling much the same. My recovery afterwards is no better. Again, I believe this has more to do with me than with the product. The gel felt heavy in my stomach, resulted in slime in my mouth and generally made me feel nauseas.

I think that I might have stumbled upon an explanation for this in an article published in the IronMan South Africa magazine (Greenfield 2012). I extracted the relevant statement:

“Most triathlons are relatively aerobic sports, and many training sessions and longer races do not necessarily use sugar and starch as primary fuels, but rather rely on fatty acids. From a biological perspective, this makes sense, since carbohydrates can be rapidly depleted, and the body can only store a few thousand calories from carbohydrates, but tens of thousands of calories from fat”.

“If an athlete is eating primarily pasta, bread, white rice, soy, processed meat substitutes, non-organic eggs and dairy, and drink a lot of fruit juice, not only could they be consuming excessive and unnecessary carbohydrate that they are not actually burning for their sport, but they may also be running the risk of developing deficiencies in essential fatty acids, amino acids, vitamin D, iron, B12 and minerals”.

“Nora Gedgaudas, a certified nutritional therapist and author of Primal Body, Primal Mind, explains it this way: Fat, in the form of ketones (broken-down fatty acid by products) and free fatty acids, is the preferred aerobic fuel for the heart and other muscles, and ketogenic adaptation provides a more steady release of even-burning and sustainable fuel. It can take a good three or four weeks to adapt to a fat-based metabolism, following which performance has been shown to be superior.”

“Nora explains that you get good at burning fat by depending on fat in the absence of carbohydrates, not by constantly depending on and burning sugar for fuel”.

     

My protein based diet translates into a fatty acid diet. Over the past six months my body has become efficient in burning fat. It has lost, to a great 

extent, its ability to process carbohydrates and sugar quickly and efficiently, which means that the gel supplement uptake in my body was inefficient. This has nothing to do with the product and everything to do with my body.

There are a great number of performance athletes who find great benefit in using these same gels.

Alternative Views

There is also mounting research that discards the idea of carbohydrates as a beneficial source of energy. The following links will provide some interesting information:

www.ericdavid.info/Home/brentwood-diet

www.terrywahls.com

www.youtube.com/watch?v=KLjgBLwH3Wc

www.discovery.co.za/email_za/mailers/pdfs/general/noakes.pdf

www.pod702.co.za/podcast/bestofjohn/20120123JRBestofa.mp3

The following authors also provide some interesting reading and research: Gary Taubes, Mark Sission, Dr Westman, Pierre Dukan, Loren Cordain.     

Conclusion

My conclusion is that energy supplement gels did not work for me; however, there is no evidence to suggest that it won’t work for other runners. My personal physiology indicates that I should maintain my intake of protein and fats. This means that consumption timing is of the essence if I am to ensure a constant performance during an ultra-event. 

Future Strategy

My focus will now shift towards refining my present diet, and not necessarily changing it. Keeping in mind that every gram of protein contains 16.7 kilojoules, and one gram of fat contains 37.7 kilojoules, I have a need based drive from which to devise a simplified and sustainable strategy.

For example, as calculated earlier, I need around 1761kJ per 30 minutes. This can be provided through the consumption of dried beef consisting of 30% fat. Such a 30/70 fat to protein ratio delivers 23kJ’s per gram translating into a requirement of 77g per 30 minutes. A 24 hour 100 miler will require 3,7kg of dried meat. This is just a crude example and is in need of a balanced composition refinement.

Over the next few months I will refine my food energy source diet, test this in late July 2012 when I run the Washie 100 mile race, after which I will report back.

Thank you for visiting my blog, please come again.

Genis

________________________________

Sources:

Note: 1 Nutritional Calorie is equal to 4.1868 kilojoules of energy.

Greenfield, B. 2012. IronMan South Africa. 70.3 Edition. 2012 Spec-Savers. Page 102-106.

Bean, A.(ed) 2006. Runner’s World Best: Competitive Running. Rodale, London. Page 78-79.

http://www.calorieking.com/foods/calories-in-eggs-chicken-egg-whole-hard-boiled_f-ZmlkPTExMjk.html

www.ericdavid.info/Home/brentwood-diet

www.terrywahls.com

www.youtube.com/watch?v=KLjgBLwH3Wc

www.discovery.co.za/email_za/mailers/pdfs/general/noakes.pdf

www.pod702.co.za/podcast/bestofjohn/20120123JRBestofa.mp3

Washie 100 Miler:  

[http://www.buffsclub.co.za/running/index.php?option=com_content&view=article&id=22&Itemid=34]