Sports Nutrition Bible

[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...

[wesrman]

Excellent thread.

[ono]

During Exercise

For most activities lasting less than an hour, drinking anything other than water is unnecessary, provided your pre-exercise muscle glycogen levels are high. So basically if you've eaten a carbohydrate containing meal 2-4 hours before, then you'll be fine with just water.

If you are exercising for longer than 60 minutes ata moderate-high intensity, comsuming carbohydrate during exercise can be beneficial. During the first 60 minutes of exercise, most of your carbohydrate energy comes from muscle glycogen. After that, muscle glycogen stores deplete significantly, so the exercising muscles must use carbohydrates from other source. That's where blood sugar (glucose) comes into it. As you continue on, more and more glucose is taken from the bloodstream. Eventually, after around 2-3 hours, your muscles will be fuelled purely by glucose and fat. Unfortunately amino acids are now likely to be used for fuel aswell as liver glycogen. Once liver glycogen runs low, you may be in danger of experiencing hypoglycaemia...which is very unpleasant.

Clearly then, consuming additional carbohydrate whilst training, would stabilise blood glucose sugar levels thus allowing you to exercise longer.

So how much carbohydrate should i have?

Around 30-60g per hour is best. It's important to consume these carbohydrates before fatigue sets in. Don't wait for it! This is because it takes around 30 minutes for the carbohydrate to enter the bloodstream.

The best strategy would be to consume the carbohydrates soon after the start of your workout (30 minutes into it at the latest).

Note: continually consuming carbohydrates whilst training will not allow to train indefinately...pretty sure you'll have grasped that anyway

Which foods or drinks are best?

High or Moderate GI carbs are best as they raise blood sugar levels and reach muscles more rapidly. Whether you choose liquids or solids makes very little difference to your performance, provided you drink water with your solid carbohydrate. Liquid forms of carbohydrates are probably more convenient. If you prefer to consume food aswell as drinks during exercise, energy pr sports nutrition bars, sports gels, ripe bananas, raisins or fruit bars are all perfectly fine. Just be sure to drink water at the same time. Whether you choose liquid or solid carbohydrate, aim to consume at least 1 litre fluid per hour.

to be continued....(sorry if it's moving slow, my comp at home is fooked)

[ono]

Suitable foods and drinks to consume during exercise

I said before that 30-60g of carbohydrate per hour, whilst training would be very beneficial. Below is a table explaining the required quantities of different foods, required to consume 30g of carbohydrates.

Isotonic Sports Drink (6g carbs/100ml) - 500ml

Glucose Polymer Drink (12g carbs/100ml) - 250ml

Raisins or Sultanas - 1 Handful

Cereal or Breakfast Bar - 1 Bar

Energy Gel - 1 Sachet

Bananas - 1-2 Bananas, depending on size

Obviously to consume 60g of carbohydrate you would have to double the portion sizes shown above.

Just a quick note on energy gels

Be sure to drink plenty of water with energy gels. If you don't consume enough water with them, you will end up with a gelatinous goo in your belly, which will drag water into your stomach which increases the risk of dehydration. Aim to consume around 350-400ml of water along with it. Maybe split this up into two servings of 175ml-200ml per half sachet. This amount of water will give it a 7% solution (in your stomach) which is the equivalent to an isotonic sports drink. Stick to the above guidelines and try not to be too liberal with the water. Whilst dehydration is a risk when consuming insufficient amounts of water, comsume too much water and not enough carbs will get inside the muscles so you won't get that vital energy boost. So follow the above guidelines for maximum effectiveness.

[ono]

I've just spent an hour adding to this thread and the fucker timed out