Sports Nutrition Bible

[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.

[ono]

So if Carbs don't make you fat, why do 'experts' recommend high protein, low carb diets?

There is a misconception (and it is actually one that i used to share) that cutting carbs out of your diet will result in fat loss. There is also a misconception that consumed protein can be stored directly as muscle.
Therefore, the advice of eating loads of protein and cutting carbs, will result in fat loss and muscle maintenence has become quite common.

The problem is, these diets are normally endorsed by some random celebrity (jade goody anyone?) who hasn't got the slightest idea of how to lose weight. Once the endorsement is there, the diet becomes popular. The truth gets lost and the dieters get frustrated as any weight they lose from the 'fad diets' returns almost as quickly as they lost it.

So why don't these diets work?

If you cut out all carbohydrates you will lose weight. That doesn't mean the diet works. You see, you will lose weight in the form of glycogen, water and lean tissue, yet the thing you most want to get rid of is still there (fat) and it's now harder to shift than ever.

For every gram of carbohydrate consumed, 3-4 times equivalent of water is also dragged into muscle cells. So when you drop carbohydrates from your diet, muscle glycogen becomes severley depleted, which in turn depletes all the water from muscle cells. So yeah, you will lose a lot of weight quickly, but it's not the right kind of weight.

On top of that, you will lose muscle tissue as you are not consuming enough carbohydrate to support your existing lean tissue. Protein will also be broken down and used for energy. To make matters worse, the less muscle mass you have, the harder it is to lose bodyfat.

Another problem with severly dropping calories (not just carbs) is your metabolism will slow right down which is also a very bad thing when you want to lose fat. The best dieting method for cutting fat is to decrease calorie intake by about 15%. Anyways i'll go into that a little bit later on.

to be continued...

[ono]

Ok, you've convinced me, i won't cut carbs...

But what kind of carbohydrates should i eat?

Ever heard of the Glycemic Index (GI index)? You probably have. The GI Index is used to describe the effect different foods have on your blood sugar levels. Low GI carbs are what you will want to base your diet around. High GI carbs may be useful during the Glycogen replenishment stage that takes place immediately after exercise (again i'll go through that later).

Not all carbohydrates are equal!

This will become apparent to you when you look at the GI Index (which i will go through soon). It's tempting to think that simple carbs are absorbed quicker than complex carbs, and that they produce a large and rapid rise in blood sugar. Unfortunately it's not that simple. For example, apples (containing simple carbs) produce a small and prolonged rise in blood sugar, despite being high in simple carbs. Many complex carbs such as bread and potatoes are digested and absorbed very quickly and give a rapid rise in blood sugar. So the old notion that simple carbs give you fast energy and complex carbs give you slow burning energy is actually misleading.

So why do some fitness websites tell you to lay off fruit when wanting to lose weight?

Because they have most likely got as far as seeing that fruit is made up of fructose and fructose is a simple carbohydrate. That's probably as far as they have thought it through.

to be continued...(because it's home time )

[ono]

The GI Index

Glycaemic Index Tables

That is probably the most comprehensive GI index i have seen on the internet.

How is the GI worked out?

The GI value of a food is worked by out by feeding 10 or more healthy people a portion of food containing 50g of carbohydrate. For example, you would eat a 250g baked potato which contains 50g carbs. Over the next 2 hours a sample of blood is taken every 15 minutes and the blood sugar level is measured. On another occasion, the same 10 people consume 50g of glucose. Their response to the potato is compared with their blood sugar response to 50g of glucose.

50g of glucose equates to 100 on the GI index.

Glucose is used as the yardstick to measure everything against. A baked potato registers as 85 which means it produces a rise in blood sugar which is 85% as great as that produced after eating an equivalent amount of glucose.

So how do i integrate the GI Index into my diet?

Use the GI Index to select mainly low GI carbohydrate. Low GI should make up the bulk of your carbohydrate intake, with the exception of post workout where high GI carbs may come in handy (more on that later).

What are the drawbacks of the GI?

The biggest drawback is that GI Index doesn't take account of the portion size you are eating, For example, watermelon has a GI of 72 which makes it high, which would make it a no-no for the low GI seekers. However an average slice (120g) only contains around 6g of carbs. So you would need to eat around 8 slices to obtain around 50g of carbs - the amount used in the GI test.

Also many (not all) vegetables appear to have a high GI value. However their carbohydrate content is so low that you would have to eat an absolute mountain of it for it to have any significant effect on blood sugar.

Another drawback is that some foods that are high in fat have a low GI value. The GI of crisps or chips is lower than the GI of a baked potato. Fat reduces the rate at which food is digested but saturated and trans fats can push up heart disease risk.

The bottom line is this - Don't just select foods by their GI value. Check out their protein and fat content aswell. Watch out for saturated and trans fats!

[ono]

So know you know about the glycemic index, so you should hopefully be able to select the right sources of carbohydrates to support your goals (low GI, pretty much all the way).

You also know how many grams of carbohydrates you need daily, to support your existing weight and exercise levels.

So taking into account that you should aim to eat a small meal every 3 hours (6 times per day, roughly), you should now be able to figure out just how much carbohydrates are required with each meal...

Before you simply divide you total intake by 6, please read on...


Pre-Exercise

Ideally you should consume a meal 2-4 hours before training. This will enable enough time for your stomach to feel settled which should help you to have a comfortable work out (not too full - not too hungry).

Obviously the time of the meal will very much depend on your daily schedule and the time of day you plan to train.

A little bit of trial and error may be necessary here to figure out what works best for you. Eating too close to your training session may make you feel too full and uncomfortable, whereas leaving too long an interval between eating and training puts you at risk of hypogylcemia (low blood sugar...pretty shitty feeling to be honest).

How much Carbohydrate?

Most studies seem to settle on around 2.5g carbohydrate/kg of bodyweight, around about 3 hours before exercise. This sounds like an awful lot, but when you consider that a 45 minutes weights session can deplete around 40% of total glycogen stores then the figure doesn't seem so ridiculous.

So the average 70k athlete would need to consume 175g carbohydrate 3 hours before exercise.

I know this may go against peoples conventional wisdom and a few skeptics are probably worried about fat gain from consuming too many carbohydrates, but maximum glycogen storage is very beneficial when you're about to embark on an intense bout of exercise.

Of course you may need to experiment to find the exact quanity and timings to suit yourself but following the above guidelines will stand you in very good stead.

to be continued...