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We shall cover:

Overview of Carbohydrates
What are Carbohydrates?
Examples of High Carbohydrate foods
The different Categories
Fast or Slow Carbohydrates
Simple Carbohydrates
Mono-Saccharides
Di-Saccharides
Complex Carbohydrates
Poly-Saccharides
Dietary fibre
Understanding Glucose
What is ATP?
Glycogen
Does sugar really turn into Fat?
How much Carbohydrate should we eat?
Low-Carb Diets


Overview of Carbohydrates

Carbohydrates take a great deal of flack and are often portrayed as something you should cut down on. The average diet does in fact probably fall short of carbohydrates; at least they fall short of the right kind of carbohydrates anyway. The most overeaten food type in developed countries is actually fat. You will find that many sweet products that are high in carbohydrate are also high in fat.

Low-Carbohydrate diets (Low-Carb) have been around for many years now. They sometimes become hugely popular and sometimes lose the limelight. More is said about Low-Carb Diets later in this article.

If you take a rational approach to the carbohydrate issue then you will find all the answers you need. Too many people take the approach that there is a “one-size-fits-all” solution for everyone. People also go from extreme to extreme. The approach of this site is to encourage the appreciation of individual requirements.


What are Carbohydrates?

Carbohydrates (most often referred to as carbs) are made from Carbon and Water; hence the name, “Carbo-Hydrate.” They are sugar compounds that are made by plants. Plants breathe in Carbon-dioxide and the carbon component is combined with water to produce the carbohydrate. Yes… sugar is quite simply the combination of water and the carbon from the air we breathe! For further details please refer to the page, “The 4 Basic Elements of Life.”


The Different Categories

Carbohydrates come in 2 different types; simple and complex. The most basic way to explain this is; it implies the number of “sugar units” that the carbohydrate contains and the way in which they link to each other. Simple carbs have 1 or 2 units, complex carbs have many. To summarize:


Simple Carbohydrates
 
Mono-Saccharides
Di-Saccharides


Complex Carbohydrates (Poly-Saccharides)

Starch
Dietary Fibre


Fast or Slow Carbohydrates

Before we cover the different types of Carbohydrates it is important to explain a few things about energy release from food. This can actually be quite a confusing issue but with a little bit of knowledge things become far clearer (most of the time).

As a general rule; the more “refined” a carbohydrate is, the quicker it will release energy. This is to do with how fast the sugar gets turned into “Glucose.” Glucose is otherwise known as “blood sugar”. A system has been developed to measure this affect and it is known as the Glycemic Index (GI) of the food. Basically, the faster the carbohydrate turns to blood sugar, the higher the GI. It is measured in a scale from 1 – 100.

There has been much talk about GI in the media since it was developed. You will possibly be surprised to find that things like bread and crackers actually have a higher Glycemic Index than chocolate bars and even table sugar! Certain types of food combined together with the high GI food bring down the overall GI of the meal. One of these is fat and another is dietary fibre.

It is important that you don’t get complacent about the fat part of food. Adding fat to a meal to reduce the GI is not an ideal methodology. Generally, people who eat a large amount of natural whole food do well where GI is concerned. Consumption of fibre is the most beneficial way of maintaining a good Glycemic Index. This is one of the main reasons why whole foods are the key to good health.


Simple Carbohydrates

Simple carbs are subdivided yet again into simple and double sugars. They are characterized by their sweet taste and the way in which they provide a quick burst of energy to the body:

Mono-Saccharides (Simple sugars): These include fructose (from fruit), galactose (from the lactose in milk) and glucose. These contain 1 sugar unit.

Di-Saccharides (Double sugars): An example would be sucrose which is the sugar that we are generally well acquainted with, the one that people put in tea or coffee. It is a double sugar because it is made up of one unit of fructose and one of glucose.

Unfortunately humans have discovered the ability to extract sweetness from carbs and eliminate the rest. This kind of refinement is not good in a healthy diet and refined sugar should not really be consumed at all.

Because most complex carbs are considered more desirable, confusion can arise over whether “fast” carbs are healthy or not. Fruit is highly beneficial even though it contains simple sugar (fructose). It is extremely important for good health and aids in fat loss. They are usually fairly slow release in nature because fructose has a very low GI and the sugar is bound up in the fibre contained in the fruit.

Some types of dried fruit are a different matter. You will notice on GI charts that things like dates are very fast at releasing energy. Dates are in the mid nineties, depending upon which resource you use. Anything above 70 is considered “high”.


Complex Carbs (Poly-Saccharides)

Starch Foods

These are often known as slow release carbs… but not all of them are so slow. Some are even faster at turning into glucose that the simple sugar foods. They include grains, vegetables, beans, rice etc. Certain types are considered vital to a healthy diet because they release energy to the body slowly and gradually as opposed to the burst of energy you get from simple carbohydrates.

Some of the slower releasing carbohydrates include oatmeal, “brown” rice, lentils and many types of beans. Some rice and certain types of pasta are also reasonably slow release.


Dietary fibre

Dietary fibre is a polysaccharide as well as starch, but it is not the same. It is not a source of energy due to the fact that the human body cannot break it down. It is highly desirable in a healthy diet however. Our bodies are designed to eat food rich in fibre. It is important for giving bulk to your solid waste and slows down the conversion of carbohydrates to glucose.

People in developed countries like UK and USA tend not to eat any where near enough fibre due to the amount of refined foods in the average diet. People tend to only refer to the way that fibre gives bulk to faeces but it has many other benefits as well. Fibre from vegetable and fruit slows down the absorption of sugar into the bloodstream and helps to keep a steady level of energy. Meat lacks fibre and so do many refined foods. Ideally, plenty of vegetation should therefore be included with any type of food that does not contain its own fibre.

There have often been times when people have been encouraged to eat a bran breakfast. This is better than nothing at all supposedly, but it is not taking into account the fact that you need fibre with each meal. Some of these bran cereals tend only to be eaten in the morning which means that it will not be combined with food that you eat throughout the day. Not only that; bran is not one of the best forms of fibre. The best, most readily available fibre is the type you find in leaves, root vegetables and fruit.

The best way to make sure that you get enough fibre is to ensure a vegetable rich diet with plenty of whole foods. Many “Vegetarians” tend to do pretty well where fibre is concerned… as long as they do actually eat a good diet and not just refined, processed foods.


Examples of Good Carbohydrate food

Most food has a certain amount of carbohydrate in it, regardless of what it is. Some have considerably more than others though. In the following lost I will show you a few of the most common ones and I have given ALL the Macronutrients for the sake of comparison.

Starch foods

Bread
Oats
Rice
Potato

Beans (legumes)

Lentils (dry and raw)
Kidney Beans (canned and drained)

Fruit

Apple
Banana
Orange
Plum

Notice the amount of macronutrients compared to the weight of the product. I have given them in 100g amounts so that you can clearly see the “percentage.” I have not put down the water content. When the total figures do not add up to 100 then the rest is water or things that do not count.


Understanding glucose

Glucose is actually the fuel of the human body. All processes including that of the brain use glucose. Carbohydrate sugar needs to be converted first because the cells of the body only run on glucose. For example, fructose from fruit may be carried in the blood but it still needs to be converted before it is put to use. For this reason, fructose is still referred to as slow releasing.

Once the glucose is inside the cells of your body it is “burned” to produce heat and a substance known as ATP is produced. This molecule stores and releases energy as required by the cell.


What is ATP?

ATP, otherwise known as “Adenosine Triphosphate” is something that your body cells create from glucose. It is often referred to as the body’s energy “currency.” It is a temporary store of energy produced as a result of “respiration” within cells. It is used to contract muscles.

If you study higher level biology books then you will more than likely end up being more confused than what you were before. Keeping the subject of ATP simple is actually fairly difficult. A thorough understanding is only really required if you wish to look deeply into the biology of organisms. It is outside the scope of this section of the site.


Glycogen (animal starch)

Glycogen is a substance that is created by the conversion of excess glucose. It is stored in the muscles and the liver. Glycogen is in fact a carbohydrate, hence the reason why it is referred to as animal starch. All other carbohydrates are produced in plant matter.

The average human body stores a total calorie value of about 1800 in the muscles and liver. This tends to come up to around 400g in mass but that obviously varies from person to person. Once that limit is reached then apparently all of the excess will be converted into fat.


Does sugar really turn into fat?

This is one of the areas of nutrition where many people seem to be in disagreement with each other. Some people will say that sugar does not turn into fat because there is no scientific “proof”. You will find, however, that most of the professional nutritional researchers agree with the (somewhat complicated) theories that describe how sugar is converted to fat for storage.

It is believed that the human body condenses energy from unused glucose by turning glucose into fat. This is a very believable theory because there is no reason why the cells of the human body should not be able to do that. The chemical structure of carbohydrate (sugar) is similar to fat although it has a different molecular structure. Fat contains far few oxygen molecules and is formed into long chains.

One theory in favour of the "sugar does not turn to fat..." school of thought will suggest that sugar does not turn to fat; it just stops fat from being burned so much. Sugar is used first because the body will process the food stuff that is easiest to burn - it is easier for the body to process sugar to produce energy than it is to process fat.

The fact is… either way; if you consume excess quantities of carbohydrates you will put on fat regardless of which theories are correct. That is the main thing you should be concerned with. Fat is stored when you consume “more calories” than you can burn off. You are going to have difficulty finding food that contains no fat at all. If you did then it would not be healthy anyway due to the fact that all whole foods contain fat to some degree. Certain fats are also essential for the body.


How much Carbohydrate should we eat?

Carbohydrates should make the bulk of the human beings diet. Human beings crave for the taste of sweetness in the same way as a cat or dog craves for the taste of protein. Although craving may implant into peoples mind something that is bad, it is actually an indication of a requirement.

Rest assured that carbohydrates are a very important part of a healthy diet. They should make up the bulk of your diet as opposed to the teachings of some low-carb philosophies. As a general rule you will find that most advisors will recommend about 50% of daily calories as carbohydrate. The other 50% should be distributed between Protein and Fat. There will be more on that in the relevant section.





Low-Carb Diets

These types of diets must be treated with caution for they can be hazardous to health. I would not necessarily condemn them entirely because that would be a very “black and white” attitude. There may be times when diet changes (even if temporary) can achieve something that you would otherwise not. The key is to understand what is involved. If you are not interested in learning about them then leave Low-Carb Diets well alone!

Body builders will sometimes use low carbohydrate diets before a competition. You may consider that unhealthy, and in some respects it is. They would not normally use a low carbohydrate diet under normal circumstances. All low carbohydrate diets should only be temporary unless you have a condition that makes you sensitive to carbohydrates in general.


Summary

Carbs are vital to good health…

It must be stressed how important this food group is in the human diet. Any attempt to eliminate or reduce the quantity of carbs from your diet will most likely cause problems. Some people are carbohydrate sensitive but that is not a good reason to completely eliminate carbohydrates altogether.


Further reading:

Burn the Fat – Feed the Muscle
Optimum Nutrition Bible
Eating Well For Optimum Health
Nutrition for Dummies


For “Deeper” reading:

Any higher education publication on Biology (Post High School).
UK… A-level Biology books
A-level Chemistry for details about atomic/ molecular structure