Are you confused about carbohydrates? Do you keep hearing about fast carbohydrates and slow ones, simple carbohydrates and complex carbohydrates? Have you heard about the successes people have with a low carb diet but you still don’t understand how this can help you? Do you want help losing weight? Do you need to understand how carbohydrates affect your blood sugar levels? It turns out carbohydrates may have a big impact on whether you are overweight or not. But what exactly is a carbohydrate?
With this article I will take the mystery out of carbohydrates and how they impact our bodies.
There are basically three main groups of food that we eat: proteins, fats, and carbohydrates. For years we were told that we could lose weight by lowering the amount of fat in our diets. We were also told that cutting out fat would make us healthy. This started the low-fat craze with all types of low fat products showing up on the grocery store shelves.
You would think that with all the emphasis on eating low fat –from low fat salad dressing to low fat bread- we would all be thin and we wouldn’t have any more diabetes But that did not happen, something strange took place instead. During the time that fat in our diets was viewed as the enemy, we actually got a lot fatter as a nation and the rates of Type 2 Diabetes shot through the roof. So what happened?
It turns out that fat may not be the enemy after all. Instead, high levels of refined carbohydrates in our American diet may be mostly to blame. The fact that we are exercising less and eating larger portions also plays a part, but lets take a look at the carbohydrate piece of the puzzle first.
What Is A Carbohydrate
A carbohydrate is any food that is made out of sugar molecules. That’s right, carbs are actually just groups of sugars bonded together. Carbohydrates can be divided into three main groupings: sugar, starch, and fiber. You wouldn’t think that bran fiber is made by sticking a bunch of sugar molecules together but it is true.
The most basic sugar molecule is called glucose (pronounced glue-kose). It is formed by combining hydrogen atoms, oxygen atoms, and carbon atoms. A representation of the glucose molecule looks like this:
Representation of a Simple Carbohydrate – Glucose
Don’t let this picture scare you into thoughts of high school chemistry. There won’t be any tests. You can understand what a carbohydrate is without understanding this picture. I just included it in case you are interested in how the oxygen, hydrogen, and carbon combine to make a simple sugar molecule called glucose.
The term carbohydrate comes from the elements that make up the molecule. CARBonOxygenHyDRogenATE. As you can see, the word carbohydrate is made by using parts of the names of the three basic elements.
The picture above represents the type of sugar called glucose. This is a very important type of sugar because it is what fuels our bodies. Everything we do with our bodies from using our brains and thinking to using our muscles for lifting weights is possible because we have glucose in our blood and we can use it to power the cells in our bodies. If we didn’t have the fuel that glucose provides then nothing would work. So glucose (also called blood sugar) is a good thing. The problems develop when there is too much glucose because then it is stored as fat.
What Are Simple Carbohydrates
Simple carbohydrates are basic sugars. Along with glucose there are two other sugars that are formed with just one molecule. They are galactose which is a sugar molecule found in milk products and fructose which is a sugar molecule found in fruit. The difference between these sugar molecules is how the hydrogen, oxygen, and carbon atoms are arranged.
These three simple sugar molecules can be combined to form other sugars that are also considered simple. A lactose sugar, which is found in milk, is made by combining one galactose and one glucose. When you hear of people being lactose intolerant this means they can not break down this lactose sugar molecule into its two individual molecules.
The most common sugar in our lives is sucrose. This is the name for table sugar. The white stuff we sprinkle on cereal and use in baking. A sucrose molecule is formed when a fructose and glucose molecule are combined.
Glucose, galactose, fructose, lactose, and sucrose are all classified as simple carbohydrates because they are only one or two molecules in size and they are quickly absorbed into the blood stream during digestion. Don’t let the names overwhelm you. Just remember that carbohydrates are made of sugar. This is the key to understanding how they can help us lose weight or gain it and of course how they affect our blood sugar levels.
What Are Complex Carbohydrates
Complex carbohydrates are just groups of these simple sugars bonded together.
They either form end to end or they combine to look like the branches of a tree. Have you ever seen small magnets that stick together to form larger clumps? That is a good way to think about these complex carbs. The simple sugars are like individual magnets and they bunch together in different ways to create everything from wheat to potatoes to corn and rice.
How these sugars are connected determines whether they are easily broken apart during digestion and the sugar absorbed, or whether they pass through the body without being changed like fiber does.
For years it was thought that simple carbohydrates where bad for you because they would be absorbed very quickly into the blood stream and that complex carbohydrates were good because they would not break down very fast and be absorbed. Unfortunately, it is not as simple as that.
Some of these large, complex carbs break down very quickly. Examples of these would be cooked potatoes, cooked white rice, and white bread. But some of these large molecules are never broken down such as wheat bran and other fibers. And some are broken down into their sugars but it takes a relative long time for the digestion process to occur.
What Are Good Carbohydrates
Since some complex carbohydrates do not digest into sugars at all and some digest and enter the blood stream very quickly we can not just say that all complex carbs are good or bad. We need another way to look at foods with carbohydrates to determine if we should eat them or not.
This new tool is called the Glycemic Index. It is a measure of how fast the sugars from a particular food are digested and enter the blood stream. This is determined by having test subjects eat a particular food and then their blood sugar (glucose) levels are checked several times to see how fast the sugar is absorbed.
Since we are interested in the speed at which simple sugar glucose is digested a good starting point would be to see how fast a mixture of straight sugar (glucose) and water is absorbed. We find that there is a very dramatic rise in blood sugar levels and then a drop off. The amount of rise in sugar (glucose) in the blood when straight sugar is consumed is given a value of 100.
Every food can then be tested and the amount of blood sugar increase compared against the value of 100 for straight glucose. Most foods are going to have a Glycemic index number less than 100. So for example a raw carrot is going to have a Glycemic index of 30. This is low and will not raise the blood sugar levels very much so it would be a good food to eat.
But cooking foods can change the structure of the carbohydrate molecules and thus make them easier to digest. This means the sugars will enter the blood stream faster. So our carrot that has a value of 30 when raw has a value of 85 when cooked. This means we would want to eat raw carrots and not cooked carrots.
Potatoes are another example of the change in sugar digestion that occurs with cooking. A boiled potato in its skin has a GI (Glycemic Index) of 70 but instant potatoes that have been processed have a GI of 95. So instant mashed potatoes raise the sugar levels in your blood almost as much as straight sugar water does. We definitely don’t want to be eating that.
Current research seems to indicate that eating foods that cause a spike in blood sugar can be a cause of Type 2 diabetes and also weight gain. If we are interested in controlling diabetes or losing weight, then we want to eat foods that do not have a dramatic effect on blood sugar. This means we want to eat foods with a low Glycemic Index.
List Of Carbohydrates
So we have seen that carbohydrates are nothing more than sugar molecules grouped together in long chains or branches like a tree. Some of the carbohydrates are easily digested into sugar and absorbed into the blood stream and some are not. The measurement of how fast the sugars in a particular food are absorbed is called the Glycemic Index of the food.
A high GI (Glycemic Index) number means the sugars are absorbed quickly and these are foods we want to stay away from. A low GI number means the sugars are not so quickly absorbed and so these are foods we do want to eat.
One way that the GI number for a food can be increased is by processing it from its natural state. So for example hamburger buns have a GI of 95, and are made from highly refined flour. Whole wheat bread, on the other hand, can have a GI as low as 50 and bread made from unrefined flour may be as low as 40.
What Are Starch and Fiber Carbohydrates
A starch carbohydrate is a molecule in which the individual sugars are not bonded together very tightly. This means the molecule is easily broken down into its individual sugars which are easily absorbed into your blood stream during digestion. This causes a quick rise in your blood sugar levels.
Common starches like those found in potatoes, corn, and grains are easily digested and converted to blood sugar because the individual sugars in the starch molecule do not hold onto each other very tightly. When we cook starches this weakens the bond even more. That is why pastas that are still slightly firm after cooking have a less drastic affect on your blood sugar than pastas which is are cooked until they are very soft. The bonds just get weaker. You can see this when you over cook pasta and it becomes mushy.
If you are on a low carb diet then you definitely want to limit the amount of starchy foods you eat.
Is Fiber A Carbohydrate
Fiber is a carbohydrate that passes through the body un-digested but it is still very important to good health. It is made up of individual sugars like starches but unlike starch the bond between the sugars in fiber is very strong. Our digestive system can not break the fiber molecule up into its sugars so the fiber just passes right through us.
There are two kinds of fiber, soluble and insoluble. Soluble (dissolves in water) fiber grabs onto fatty substances in the intestines like LDL (bad) cholesterol and carries them out of the body. Insoluble (does not dissolve in water) helps to add bulk to the waste we are trying to get rid of from our bodies and helps these wastes to move out. This is why fiber is good for constipation.
You need both soluble and insoluble fiber in your diet.
Nuts and seeds
Dry beans and peas
It is recommended that you eat 14 grams of fiber for each 1000 calories you eat. So if you eat 2000 to 2500 calories a day then you need 28-35 grams of fiber a day. Since fiber is a carbohydrate it is included as part of the total carbs on a nutritional label. It is also shown separately so you can subtract it out of the total. When you are counting carbs you can subtract fiber because it is not absorbed by the body. So if you have 10 total carbs and 3 fiber carbs you only need to count the 7 carbs. You subtract the 3 fiber from the 10 total.
I hope this article has helped you to come to terms with the idea of a Carbohydrate. Remember, there are three types of carbs: individual sugar molecules, starches made up of sugar molecules that are weakly bonded together, and fibers which are made from sugar molecules that are tightly bonded.
When we are eating a low carb lifestyle we limit the amount of sugar and starch we eat. We don’t worry about the fiber except to be sure we have enough to keep our digestive system operational.