Sports Nutrition Bible

[Salty]

I think you've got the lactate shuttle a little wrong mate, the way I understood it worked was...

1. Pyruvate (pyruvic acid) is formed when glycogen and glucose are being broken down at high rates in your muscles (called glycolysis which is the conversion of these into pyruvate). Pyruvate is then converted to Lactate (lactic acid) as it increases in the muscles.
2. Lactate is now formed and transported away from the muscle cells into surrounding tissue and blood. This allows glycolysis to persist and thus continuing the supply of energy to our muscles.
3. The muscle cells which the lactate is transported to can cause the lactate to be broken down to fuel (mainly ATP) or can be used to build glycogen.

[ono]

Yeah sorry i missed out how pyruvic acid accumulates. Anyways i'll give it a go...

When pyruvic acid accumulates in our muscles (which normally occurs after a slight increase in exercise intensity) lactic dehydrogenase(spelling) converts it into lactate. Under moderate-to-high exercise intensity, lactate is converted back to pyruvic acid, which then can be broken into ATP (in the presence of oxygen, of course).

As far as i am aware, pyruvic acid does convert to lactate, but lactate can also be converted back into pyruvic acid.

I hope that explains it a little better...i was rushed for time trying to finish the chapter before my dinner ended at work :-)

[ono]

Carbohydrates

In a an age where low carb-high protein diets are 'the shit' one can be forgiven for not realising that carbohydrates play an essential part in everyday nutrition. The scary thing is, they play an even more important part in sports nutrition.

I say scary because an awful lot of fitness magazines give you allsorts of crazy advice about carbohydrates...

'don't eat fruit, it's full of sugar'

'carbs before bed will make you fat'

In this chapter i'm going to try to explain the importance of carbohydrate. I'm going to try to explain proper glycogen replenishment and why it's vitally importance. I'm going to go into 'carb loading'

I'm also going to go into the GI index, as well as touch upon pre and post exercise carbohydrate.

Finally i'll explain how to work out, how much carbohydrate you need for your particular sport while hopefully dispelling a few myths along the way.

to be continued....


ps, my pc isn't available for me to use at home so this thread may be slow for a few days. Please be patient

[yvonne]

Some really good stuff there me freind.I'll be keeping tuned in!

[cpcompany]

Top notch thread. CHeers.
I am looking forward to reading the rest of the Carbohydrate info so hurry up and get a move on you workshy bastard! lol

[ono]

Carbohydrates

There are different types of carbohydrate and each type is treated differently by our bodies. For example, glucose and bran are both carbohydrates, but they are on different ends of the energy spectrum. Glucose enters the bloodstream quickly and initiates a high insulin response, while bran never makes it into the bloodstream because of it's indigestibility. It mediates the insulin response by slowing the rate that other energy sources enter the bloodtsream at.

So what does this mean for athletes?

It means that athletes should carefully consider which type of carbohydrate to fuel up. Glucose is the main source of fuel for muscular activity, so when glucose runs out, the athlete stops performing. Therefore, understanding how to prevent glucose from depleting should be the main focus of an athletes nutrition practice.

As stated before, they are different types of carbohydrates and they are split up into 2 categories.....simple and complex. (there is actually another category containing mannitol, sorbitol etc... which is the stuff found in sugar free chewing gum, but it's not so important for this topic).

Anyways...

Simple carbohydrates (sugars) are split up into the following...

Monosaccharides (single molecule carbs) - Glucose (also known as dextrose), fructose and galactose.

Disaccharides (two molecules) - sucrose, Lactose and Maltose.

Complex are split up into the following...

Oligosaccharides (3-20 molecules) - maltodextrins for example

Digestible polysaccharides (20 plus - molecule starch carbohydrate) - these complex carbohydrates should provide the main source of carbohydrate energy

Indigestible polysaccharides (20 plus molecule non starch carbohydrate) - these types of carbs provide fiber.


Now that complicated stuff is out of the way...

It's not really essential for any of you guys to know that stuff, it's just best that i cover it anyway.

So where do all the carbs go?

Humans can store somewhere in the region of 350grams in the form of muscle glycogen, and additional 90g in the liver and around 5g circulates in the blood. The larger the muscle mass, the greater storage capacity, but also the greater the potential need.

Once all glycogen replenishment is complete, excess carbohydrate may be transported to fat/muscle cells where it will be stored as fat.

Glycogen stores and replenishment

Sports nutrionists recommend that regular exercisers consume a diet which is relatively high in carbs and low in fat. This recommendation is based on the fact that carbohydrate is very important for endurance exercise since carbohydrate stores - as muscle and liver glycogen - are limited. Depletion of these stores results in fatigue and reduced performance. Think of a car that runs out of petrol/gas.

This is why pre-exercise glycogen stores need to be full. This is why you see boxers load up on carbs before a fight.

[ono]

So how much carbohydrate do i need?

I'm sure a few of you reading this are now thinking about your own carbohydrate intake. Could it be that you have severley under-estimnated your body's need for carbohydrate?

Below is a table to use and it shows how much carbohydrate is neede by an individual to support their own energy requirements.

Activity level---------------(g) carbs / kg bodyweight / day

3-5 hours/week---------------------- 4-5
5-7 hours/week---------------------- 5-6
1-2hours/day------------------------ 6-7 (number of hours of
2-4 hours/day----------------------- 7-8 moderate intensity
more than 4 hours/day--------------- 8-10 exercise or sport)


So that means that the average 70kg guy who exercises for one hour a day, would need 420g of carbohydrate per day, just to support his energy requirements. (70x6=420g). It's quite scary to think just how much is required for the guys who train for 2-4 hours per day at a high intensity.

But won't all these carbs get stored as fat?

Ultimately no, because exercise depletes glycogen stores. So the carbohydrates taken in would go towards replenishing lost glycogen. You see, glycogen replenishment is sorta like refuelling your car.

[jem]

Wow..pretty awesome thread. especially the part on creatine. Its good to know that the guys who spend a bomb boasting that they are pumping up using creatine are pissing it out. lolz...but what about supplements that provides amino acids? Do those turn to nitric acid and urea? lolz

[Dr Strange]

fascinating.

I have been looking for CURRENT, reliable sources. I'm not really included in the fraternity of nutrition people so I am ignorant of which books are respectable in academia.

As much as I enjoy scouring the internet and finding 90% junk and 10% fact I much prefer having a comprehensive text to read on the couch.

What course of study and specifically which texts were sources for this information?

Thanks,

[sweet_science86]

nice threads, easy to read and informative. good to see people dedicated to factual information, awesome.

[amiller]

I mainly take protein but just started creatine too. I definitely feel a difference in strength. I am thinking of trying some colloidal silver products. I checked out the site and it looks interesting but not sure I want to try this supplement line without getting some opinions on it. Any advice? I'm wanting to try out some new supplements but my money is tight.

[Trainer Monkey]

I think you've got the lactate shuttle a little wrong mate, the way I understood it worked was...

1. Pyruvate (pyruvic acid) is formed when glycogen and glucose are being broken down at high rates in your muscles (called glycolysis which is the conversion of these into pyruvate). Pyruvate is then converted to Lactate (lactic acid) as it increases in the muscles.
2. Lactate is now formed and transported away from the muscle cells into surrounding tissue and blood. This allows glycolysis to persist and thus continuing the supply of energy to our muscles.
3. The muscle cells which the lactate is transported to can cause the lactate to be broken down to fuel (mainly ATP) or can be used to build glycogen.

Everything Ive read says its Hydrogen,but keep in mind,those findings were only published a couple of years ago

[ono]

Post Exercise - carbohydrates



Glycogen Depletion

Intensive training severley depletes your body's glycogen stores. Just how much they're depleted depends very much on the intensity of the training session/event and the duration of it. Another factor that comes into it is - how full your glycogen stores were before exercise. For example, if you commenced training without adequately refuelling from the previous days exercise, you will reach glycogen depletion much more rapidly - as would a car that was running on half a fuel tank, as opposed to a car running on a full on. Simple.

The higher the intensity, the more glycogen you use. For example, explosive activities such as sprints, jumps or lifts and high intensity activities such as running will deplete glycogen stores much more quickly than low intensity exercise would.

The duration also has a bearing on how much glycogen is used. For example you would use more more glycogen running for one hour than you would if you ran at the same pace for only half an hour.

[ono]

Glycogen Replenishment and Muscle Damage

Certain activities which involve eccentric movements (heavy weight training, plyometrics or hard running) can cause muscle fibre damage. Muscle damage delays glycogen replenishment, so complete glycogen replenishment can take as long as 7-10 (when there is muscle damage).

Without muscle damage, glycogen replenishment takes around 20-22 hours provided you have an adequate nutrition plan

[ono]

I've decided to use word for long messages now to prevent what happened yesterday happening again.

So the text looks different....and smaller for some reason.