Low-carbing and athletic performance

[Guest guest]

I didn't have time earlier to do a proper job of looking for the Barry

Groves article I mentioned, but just now, while finishing my dinner, I

found it.

http://www.second-opinions.co.uk/athletic_diet.html

A few highlights:

>So what is wrong with carbo-loading?

>

>There are two problems that those who recommend carbo-loading don't appear

>to realise:

>Firstly, the body can't store carbohydrates in large quantities and most

>people already get more than enough carbohydrates to fuel their bodies'

>daily activities. All carbohydrates, whether they are bread, pasta, sugar

>or jam when you put them in your mouth, enter the bloodstream as glucose.

>And the bloodstream can only hold so much. The body, being a well-run

>power plant, puts the leftovers in storage to use in the future if it's

>needed. Some is stored as a type of starch called glycogen, but as it

>can't store much of this, the body turns most of the excess into fat and

>keeps it on deposit in the body's fat cells. And we see it walking around

>the streets wherever we go, hanging off bodies in a most unattractive way.

>Put simply, carbo-loading cannot work simply because excess carbs are not

>stored in a readily usable way.

>

>The second problem lies in how the body uses its various options for fuel.

>Each of our body's cells contains lots of very small power plants called

>mitochondria . It is they that produce the energy we need from the food

>that we consume. Glucose is usually called the body's 'preferred fuel'

>because, if it is available, our bodies have been conditioned from birth

>to use it first. But it is not the best fuel. That distinction belongs to

>fats - or fatty acids, to give them their scientific name. Before the

>mitochondria can use either glucose or fatty acid as a fuel, it has to be

>transported into the mitochondria.

>

>Fatty acids are transported into the mitochondria as completely intact

>molecules. Glucose, on the other hand, can be transported only after it

>has been broken down first into pyruvate by the process of glycolysis .

>This is then used anaerobically to produce energy with lactate as a

>by-product.

>

>The by-products of the energy-production process when fatty acids are used

>are carbon dioxide and water, both of which are easily excreted. But when

>glucose is used, the lactic acid produced in the conversion process can

>build up in muscle cells and make them ache. It is this that is the cause

>of the aching muscles or pain involved in strenuous exercise - 'the wall'

>as athletes call it. This 'wall' severely limits an athlete's performance.

I'm not sure about his assertion that it's simply lactic acid production

that causes soreness and exhaustion (I'm not sure anyone's conclusively

determined the whole truth about that) but it's certainly true that when

the body is adapted to burning fat first and foremost (which admittedly can

be a difficult thing to achieve, particularly for people in ill health who

spent years eating high-carb) glycogen stores, which are inherently

limited, are at the very least much less of an issue. In those times when

I've been relatively fit and eating a low-carb diet, I could do strenuous

physical work for hours without crashing or needing food. (I'm thinking of

some major gardening and composting projects I've done in the past. The

contrast between my ability to plug away for hours then with the crappy way

I felt when I was doing some landscaping and eating a much higher-carb diet

is extreme.)

>Now let's look at a real athlete

>

>It was 1968 at the Mexico City Olympic Games. The spectators at the

>marathon went wild as a relatively unknown Ethiopian, Mamo Wolde, won the

>marathon. Not only was the thirty-six-year-old runner the oldest man ever

>to win this prestigious event, he did it in a time that has not been

>bettered to this day.

>

>So what was Wolde's secret?

>

>Wolde grew up in an Ethiopian village. His life consisted of running after

>and hunting wild game on foot. His diet was one high in animal meat and

>fat, with practically no carbohydrate. Subsequent tests showed that

>Wolde's body, under conditions of physical load, readily burned fat as its

>main energy source. Wolde had no concept of 'hitting the wall'. It had

>never happened to him.

>Still not convinced?

>

>Athletes are told to eat a diet high in carbohydrates and low in fats.

>This, they are told, will increase their performance. However, this was

>not confirmed in a dietary study published in 1994. (5)

>

>Using three diets: normal, high-fat and high-carbohydrate, the study

>showed that the high-carbohydrate diet increased performance by an average

>ten percent over a normal mixed diet. Not bad, you might think, but the

>high-fat diet increased performance by a massive thirty-three percent.

>That's much better. The authors conclude that restriction of dietary fat

>may be detrimental to endurance performance.

>

>Experience from around the world confirms it

Here's the relevant citation:

>5. Muoio D M, et al. Effect of dietary fat on metabolic adjustments to

>maximal VO-2 and endurance in runners. Medicine and Science in Sports and

>Exercise . 1994; 26 (1): 81-88

And the part I mentioned:

>Caution

>

>There is just one caveat. It takes time for the body to change from

>burning inefficient carbs to burning fats efficiently. You should notice a

>marked increase in performance in as little as 2 to 6 weeks on a low-carb,

>high-fat diet, but maximum performance may not be reached for several months.

This version of the article says " several months " , but a different version,

available elsewhere on the web, includes his original statement that full

adaptation takes a year.

Here's that previous version:

>There is just one caveat. It takes time for the body to change from

>burning inefficient carbs to burning fats efficiently. You should notice a

>marked increase in performance after about 26 weeks on a low-carb,

>high-fat diet, but maximum performance will not be reached for about a year.

You can find that version of the article here:

http://homodiet.netfirms.com/otherssay/athletic_diet.htm

-