METABOLIC EFFICIENCY

I have had a number of conversations with athletes over the last month or to regarding this concept of Metabolic Efficiency. I decided it was time to put out a piece on this idea. I used a couple of graphics from USAT coach Bob Seebohar’s presentation at Chula Vista and I included a couple of graphics from an article he wrote in Aug 2007 – I provided the link in this piece. For more information you can check out Bob’s website at http://www.fuel4mance.com/

John Magee

Assistant Coach, Kain Performance

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Essentially when you train at the intensities and with the volume dictated by the desire to compete in triathlon training then it puts many different stresses on the body, ranging from the muscular to the mental. One of those stresses is on your energy reserves. Making sure you have appropriate energy reserves to make it through the training or race so that you get a training benefit or you perform at the level for which you have trained is obviously very important.

There are three natural systems that provide fuel for your mitochondria;

1. Creatine Phosphate system – lets not bother about this one as its use is for intense anaerobic activity – like sprinting and can be depleted in less than a minute.

2. Glycogen supplies: So depending on the intensity of your workout or race you have about 3 hours of supply – considerably less as the intensity of the effort increases.

3. Fat – even for athletes with very low body fat percentages, hypothetically there is enough energy stored in the body to get you through any race, if you could access it and if your intensity were low enough.

However there is a 4^th system – its called “What you eat before, during, and after a workout”. The fundamental purpose of eating during training and racing in the short term is to replenish the second system – the glycogen system. While its true to say that the body does not exclusively burn any one type of fuel at any one time, it does have a preference at different intensity levels. Sprinting flat out is going to preferentially burn creatine phosphate, aerobic exercise – Zone 3 & 4 type work is going to burn a combination of glycogen and fat with the emphasis on the glycogen. Around zone 1 & 2 the ration of fat being burned goes up and carbohydrates goes down. So – issue number one, on a training day that could last anything from 4-12 hours depending on the phase you are in, you are more and more likely as the hours increase to essentially “run out” of glycogen and experience the dreaded bonk. Again the same is true in a 70.3 or Ironman race. So what do we do? Well the typical response is to eat, naturally – and we practice eating - gels, bars, electrolyte drinks, PB& J sandwiches etc. We also practice race day nutrition – eating what we think we will eat during the race or what will be provided during the race and we come up with some nutritional “plan” which we try with varying success. Some make it through and it “works” in that they race OK based on their expectations. But I would argue that large group of athletes at some point during their training or in their race do not do OK and at some point their training or race performance is compromised by what we categorize as GI issues. There are also some hypothetical questions that could be raised such as “How well could I have performed if I was more metabolically efficient?”

Basically – as we often experience, the longer the training session or race, the harder it gets to keep putting food into our bodies for various reasons that we need not address here. But, the reason we are all eating is to try and replace glycogen that is being depleted as we train and race.

So is there a solution? Well, I would argue that we need to address the issues of nutrition with the same rigor that we address the core exercise disciplines of triathlon. If we just address nutrition the week before the race then we are doing ourselves a disservice. There are two major issues; the first is that all athletes should understand and practice nutritional periodization. For those wishing to know more about this issue I would recommend a book by Bob Seebohar “Nutrition periodization for endurance athletes”. The second issue is the concept of metabolic efficiency – training your body to utilize fat stores in preference to glycogen stores and thus delaying and reducing the need to ingest carbohydrates and therefore significantly reducing the risk of developing GI issues. Lets explain this concept a little more. Imagine for a moment that at any given exercise intensity level your body was burning a higher % of body fat and a lower % of glycogen. What would this mean? Well – essentially it would mean that you would not need to eat as much during the training session or the race as your body was using your glycogen reserves up at a lower rate. This concept is known as Metabolic Efficiency. Alternatively the phrase “Glycogen sparing” is also used to define the idea that because you are now more efficient at burning fats then your are “sparing” your glycogen stores and thus they do not deplete as quickly.

Take a look at the graphic below. The first graph shows the relative percentages of carbohydrate used as a fuel source compared to the relative percentages of fat used as a fuel source for a typical athlete as exercise intensity increases. At 9min mile pace the athlete is using 66% carbohydrates and 34% fats as a fuel source.

Now look at the second graph. It shows the same athlete 3 months later after proper nutrition training. At that same 9 min mile pace those numbers are now 58% and 42% and at lower intensities his efficiency is even higher, but more importantly, the athlete is now able to utilize fat supplies far more efficiently not just at this 9 min mile pace but at ALL exercise intensities. As a result the percentage of fuel he needs from glycogen is reduced at ALL intensities thus reducing the need to eat and reducing the potential of GI issues.

For more information check out this link – it was from this article that I took the two image below.

http://www.personaltrainertoday.com/articles/publish/article_712.htm

OK – so I think you would agree that this makes sense. So how do you become more metabolically efficient? Well – how do you get faster or stronger? You have to train! So in order for your body to become more metabolically efficient, you have to train it too.

This training needs to begin ideally during base training so that when you reach the build phase your body is more efficient and you can take advantage of this efficiency and reduce your need for gels, bars etc. Note that once you reach the build and race phases of the season you WILL need to eat but the amount you need should be considerably less as your body is more efficient at burning fat supplies and thus you are “sparing” your glycogen supplies.

What does this actually look like? Ideally you would start this process during a 6-12 week aerobic low intensity base phase when you are attempting at a cellular level to increase the size, number and density of the mitochondria in your muscle cells. It is during this type of training that you can start to allow your body to become more efficient by providing it with enough water and electrolyte replacement but denying it carbohydrate. This forces the body to burn its fat supplies more efficiently. In fact if you are engaged in these long, “slow” runs, rides and swims, and you mindlessly throw down a gu or a bar out of habit you are in effect short circuiting your bodies effort to become more efficient as it will immediately start to use the carbs you just consumed. Obviously you cannot start this process by going out for a 6 hour ride and eating nothing, but for any activity that is no more than 3 hours in duration, water and salt replacement would be the way to start. The two tables below summarize the overall nutrition plan for the Base and Build Phase. These two tables were taken from Bob Seebohars Nutritional Periodization presentation at USAT training and edited slightly by me

(Chart may not appear correctly. Sorry! Link to Word Doc for full report & charts)

BASE PHASE NUTRITION

Nutrient	Pre Workout	During Workout	Post workout
Fluid	0.07-0.10 ounces per pound of weight 4 hours or more before workout. 0.04-0.10 ounces per pound of weight 2 hours before workout	3-8 ounces every 15 minutes – depending on sweat rate	24 ounces for every pound of weight lost
Carbohydrate	Meal or light snack depending on when training ends	Ideally none during BASE phase	Snack
Protein	Meal or light snack depending on when training ends	None	Snack
Fat	Meal or light snack depending on when training ends	None	Omega 3’s in snack
Sodium	Naturally within the meal or Snack	Just enough to promote hydration	Minimum of 500mg for every pound of weight lost

BUILD PHASE NUTRITION

Nutrient	Pre Workout	During Workout	Post workout
Fluid	0.07-0.10 ounces per pound of weight 4 hours or more before workout. 0.04-0.10 ounces per pound of weight 2 hours before workout	3-8 ounces every 15 minutes – depending on sweat rate	24 ounces for every pound of weight lost
Carbohydrate	Meal or light snack depending on when training ends	Research says: 30-90g per hour. BUT Less is More to promote metabolic efficiency	1.0-1.2 g/kg (usually about 50-100 grams or (200-400 calories)
Protein	Meal or light snack depending on when training ends	Debatable. (Make sure BCAA’s and glutamine if taken)	10-20 Grams (40-80 calories)
Fat	Meal or light snack depending on when training ends	None	No
Sodium	Naturally within the meal or Snack	Research says around 500-700 mg/Liter of fluid. Bob recommends a Min of 800mg/Hour	Minimum of 500mg for every pound of weight lost

The last thing I want to mention is that this program assumes that you are practicing good nutrition generally. You cannot go into a training session and try and improve your metabolic efficiency if you are already depleted in terms of your glycogen supplies. Take a look at these two graphics – again courtesy of Bob Seebohar at http://www.fuel4mance.com. The first shows an athlete who is not practicing effective nutritional periodization and the second an athlete who is. Note how long it takes the first athlete to fully replenish his glycogen supplies compared to the second athlete. As athletes we essentially train 6/7 days a week and if we are fueling our bodies poorly then our energy supplies will not be replenished before the next workout is upon us thus leading to a wasted session. The second athlete is far more likely to go into his next workout and train poorly.

Please contact me or Pete if you have any questions regarding this material. Try and check out the links I provided to get Bob Seebohar’s take first hand. Bob is actually someone who we could hire to come and talk to the whole group should this topic generate enough interest. He also has a new book coming out this month that addresses this whole issue in much more detail than I have given.

John Magee – Assistant Coach – Kain Performance .