Choosing Your Carbohydrate Sources

By Xavier Fox

The fact that we need carbohydrates to provide fuel for our workouts is common knowledge. However, even with a plethora of articles out there on the subject, many people in the gym are still not aware that there are different types of carbohydrates and that how you select them can have a major impact on how you look. Choosing your carbohydrates properly can save you a lot of time and effort in the diet game as well as make the difference between having a good versus a great physique. Not all carbohydrate sources are equal, and consuming 200 calories of one type can have a completely different outcome on your system to eating 200 calories of another one. After reading this article, you should be able to choose your carbohydrates wisely and understand the reasons why many articles recommend certain foods over others.

Knowing which carbohydrate sources are optimal is much like knowing which type of fuel is best for your car. Let us assume that you have a finely tuned high performance sports car. In order to make that car run efficiently and perform at its best, you need to run quick burning high-octane fuel in it. A low octane fuel will still allow the car to run, but you will notice a decrease in horsepower and performance, and the engine may even sputter. Fuels have different chemical make-ups, and although they can all make an engine run, they will cause the engine to behave differently. It is the same with carbohydrates. Your body can produce fuel from almost any type of carbohydrate, but the different types of carbohydrates will have different effects on how the fuel burns as an energy source and this will cause your system to operate differently. Much like the racecar, the carbohydrates you select can make your body run a long and fast race, or they can make your “engine” sputter well before you reach the finish line.
Our body uses the different macronutrients for different things. Proteins contain nitrogen and are the major component responsible for muscle repair and growth. Carbohydrates are compounds of carbon, hydrogen and oxygen that combine in various ways and have various properties. We get our carbohydrates mainly from plant sources, and the carbohydrates are developed during the photosynthesis process, which is how plants use sunlight to manufacture food. So, our energy source is a by-product of plants using the sun as an energy source.
You have most likely heard conversations or read articles where the topic of discussion was simple versus complex carbohydrates. Those are the two categories of carbohydrates. Simple carbohydrates are another name for monosaccharides and disaccharides. Monosaccharides are single units, while disaccharides are two monosaccharides joined together by a molecular bond. Glucose, galactose, and fructose (fruit sugar) are the most common forms of monosaccharides. The most recognizable disaccharide is sucrose, which is a glucose and fructose molecule joined together, and it is what makes table sugar. When we ingest sucrose, it is immediately broken back down into glucose and fructose. Sucrose is used in tens of thousands of products all over the world, and when melted forms caramel. Another common disaccharide is lactose, which gives milk its sweet taste. This is a combination of glucose and galactose, and you have heard of the term “lactose intolerant,” which comes from the fact that many people have problems digesting this combination. Sorbitol, which is the alcohol form of glucose, is another popular sweetener used in a wide variety of products. However, the liver turns sorbitol into fructose during digestion. Fructose is a little more “dangerous” than other sugars, because it does not need insulin to process it as much as other dietary sugars do. At the same time, in the gut cell layer, there is something called the “disaccharide effect,” where fructose is more quickly converted to fat (triglyceride) than other sugars. Therefore, fructose has an easier path to go straight to your fat stores than other types of sugars. Most other simple sugars will at least burn as energy first, and only an overabundance becomes converted to fat.
The second type of carbohydrates, which we call “complex carbohydrates,” are also known as polysaccharides. They are polymers made up of long chains of monosaccharides. The more common forms of polysaccharides are glycogen, starches, cellulose, and chitin. These are the carbohydrate sources that do not have a sweet taste to them, and they take a lot longer to “burn” in your system, because it takes the system a long time to break the many chains apart until they are finally simple glucose molecules. Since it takes a long time for the polysaccharides to go through this process, the body does not receive a rush of sugar into the system and it does not need to counteract the rush with quick and large amounts of insulin. The carbohydrates are burned as fuel more steadily and efficiently, and they provide energy over a longer period than simple sugars do. Polysaccharides are the form of carbohydrates in plants such as rice, potatoes, yams, beans and lentils. That is why most trainers recommend these foods as carbohydrate sources over others.
Now, we will discuss a topic that will be used to provide some of the decision-making criteria when choosing which carbohydrates are best. First, we must understand that carbohydrates raise blood sugar levels, and this is associated with making the body work harder to produce more and more insulin to cover the blood sugar produced. In addition, it is not advisable to have high insulin levels. Your body is more likely to store glucose as fat when the insulin levels are elevated rapidly due to your body’s ability to use only small amounts of glucose at a time. However, you do not need to reduce carbohydrates to very low levels to lose weight or improve insulin resistance. This would actually be counter-productive to your muscle building efforts. The key is to choose your carbohydrates in a way that will keep your blood sugar levels and insulin levels steady. A measurement used to determine which carbohydrates to choose is known as the glycemic index.
Before the glycemic index was studied, most dieticians would simply tell you to avoid simple carbohydrates and to eat complex carbohydrates, and it was left at that. In the last paragraph, it was stated that carbohydrates raise blood sugar levels. This is because all carbohydrates are broken down into glucose in your system. However, depending on what type of carbohydrate it is, this process will happen at different rates. What we are learning with the glycemic index is that just because a carbohydrate is classified as complex, it does not necessarily mean that particular source of carbohydrate is a better choice than others are. By studying the glycemic index of carbohydrate sources, we can make a much more educated decision than simply eating a carbohydrate source due to its complex classification.
Plants turn sugar into starches as a storage form of energy. When you consume foods like potatoes, turnips, squash and beans, you get carbohydrates in the form of starch. Our bodies turn starchy foods into glucose to be used by our body for fuel. The same process occurs for foods containing simple sugars. Our body stores some carbohydrate in the form of glycogen in the liver and muscles to be used as a short-term source of energy, but most glucose is used as immediate fuel. It has been assumed that foods in the complex carbohydrate category – such as starchy vegetables and whole grains – are all absorbed more slowly than “simple” sugar foods due to their complexity and long chains.
The glycemic index has shown that categorizing a carbohydrate as simple or complex does not tell the whole story. The glycemic index of a carbohydrate tells us how quickly it elevates blood sugar, and therefore allows us to know how the carbohydrate source will affect our insulin levels. Through studying the glycemic index of carbohydrates sources we have learned that there are simple carbohydrates that actually raise blood sugar levels slower than some complex carbohydrate sources. This is valuable information for people trying to stay in shape, but it is particularly important to those that suffer from diabetes.
When reviewing tables that list the glycemic indexes of foods, the higher the glycemic index (GI), the more quickly the blood sugar elevates after eating that food. The way the glycemic scale was determined is by giving glucose a value of 100. Studies were performed with volunteers eating 50 grams of carbohydrate from a specific food. Blood sugar readings were taken every 15 minutes for two hours after eating that food. The volunteers’ blood sugar response was measured and compared to their response to 50 grams of glucose given as food. The test was repeated to get an average reading and then added to the results from eight to ten other people to get a final number, which is the glycemic index of that food.
Therefore, a carbohydrate could be compared against glucose for raising blood sugar levels and assigned a rating depending on how quickly it caused blood sugar levels to rise. A glycemic index of 55 is considered low and a glycemic index of 70 or above would be considered high. Values between 55 and 70 would be moderate. Low glycemic index foods (foods that raise blood sugar slowly) are considered healthier because the energy released is slow and sustained. High glycemic index foods encourage a quick release of glucose and insulin that stresses the body. This quick release, or “spike,” can cause low energy, food cravings, hypoglycaemia, elevated cholesterol levels, hormonal imbalance, kidney stones, and high blood pressure.
One quick word to the wise… as with many scientific “rules,” the glycemic index does have a couple imperfections to watch out for. Although the glycemic index provides some very useful information, it should not be the only measure of the value of the food. For example, a can of Coca-Cola has a glycemic index of 63, while five dried dates have a glycemic index of 103. It should be obvious that the Coca-Cola is not to be used as a carbohydrate source instead of dates. Factors that influence how quickly blood sugar is raised by a food include its chemical composition, how long the food is cooked (to break down the carbohydrate molecules, making them more quickly absorbed), and what other foods are eaten with the food. For example, bread by itself might be quickly absorbed, but bread and margarine takes longer to break down because of the presence of fat. Therefore, if you eat a food that has a high glycemic index along with some fat or protein, it will change how the food is absorbed and reduce the importance of the glycemic index. Foods are not typically eaten alone; they are normally eaten along with other foods, which affects how quickly that food is digested. When you eat high glycemic index foods together with low glycemic index foods, you can average the effect. In some cases, the glycemic index of a food is based upon improbable amounts of the foods (amounts that a person would not usually eat in one sitting). To get 55 grams of carbohydrate from bread, it takes about 3.5 average slices. On the other hand, to get 55 grams of carbohydrate from carrots, it takes about three cups of carrots!
So… what are you supposed to do if the glycemic index does not tell the complete story, and the glycemic measurements may have been based on a ridiculous amount of the carbohydrate source? Good thing you were smart enough to ask! You also consider the glycemic load. This number will give you a much better understanding of which carbohydrate sources are actually better.
The glycemic load is based on the standard serving size of that particular food. Let us go back to our carrot example. Since carrots only contain about 7% carbohydrates, in order to get 50 grams of carbs, a person would need to eat 1.5 pounds or three cups. Obviously, foods that contain a higher percentage of carbohydrates would have smaller portion sizes for glycemic index testing. The glycemic effects of foods containing a small percentage of carbs are likely to be overstated, while the glycemic effects of foods containing a high percentage of carbs are likely to be understated. The glycemic load number tells you how much carbohydrates an actual portion size will contain instead by how much the quantity that contains 50 grams of carbohydrate will raise your blood sugar levels. It gives you an additional indicator when trying to decide which carbohydrate sources are best.
Glycemic load is calculated by dividing the glycemic index of a food by 100, and then multiplying the usable carbohydrate content in a serving size. So, our carrots have a glycemic index of 47, and they contain only 7 grams of carbohydrates per 100 grams (remember… they are only 7% carbs). If you were to eat a standard 50 gram portion of carrots (that’s 50 grams total weight, not a volume large enough to contain 50 grams of carbohydrate), there would only be 3.5 grams of carbohydrates (100/50 = 2, so divide 7 by 2 to get 3.5). Therefore, the glycemic load would be 47/100 x 3.5 = 1.65. Notice the glycemic load of 1.65 is very small in comparison to the glycemic index score of 47. This tells us that there are not many usable carbohydrates in a serving of carrots, and since there are not many usable carbohydrates, a serving will not raise your blood sugar levels much.

Food	Glycemic Index	Glycemic Index Rating	Glycemic Load Rating	Serving Size (grams)	Carb Content By Weight (%)
Cream Of Wheat	66	Medium	17	250	25.8
Wheat Bread	53	Low	11	30	20.8
White Flour Bread	70	High	10	30	14.3
Apple	38	Low	6	120	15.8
Banana	51	Low	12	120	23.5
Unsweetened Orange Juice	53	Low	9	250ml	17.0
Beetroot	64	Medium	5	80	7.8
Broccoli	0	Low	0	80	0.0
Brown Rice	50	Low	16	150	32.0
White Rice	69	Medium	30	150	43.5
Potato	85	High	26	150	30.6
Sweet Potato	37	Low	13	150	35.1
Lentils	29	Low	5	150	17.2
Long Grain Rice	56	Medium	23	150	41.1
Squash	0	Low	0	80	0.0

When comparing two carbohydrate sources, you can better select the right one by using the glycemic index and the glycemic load together. Let us compare two foods with similar glycemic index scores to choose which is better. Cream of wheat has a glycemic index of 66 and a glycemic load of 17. White rice has a glycemic index of 69, which is very close to that of cream of wheat. However, the glycemic load of white rice is 30, which is close to double that of the cream of wheat, which means that a standard serving of white rice will elevate your blood sugar levels much faster and higher than a standard serving of cream of wheat. The serving size for cream of wheat is much larger than that of white rice, so it is also likely that white rice has a higher percentage of useful carbohydrates per volume than cream of wheat. Therefore, if you are a bodybuilder, you may wish to stay away from the white rice except for after your workout when you need higher glycemic carbohydrates. On the flip side, white rice has much more carbohydrates per weight, so you will have to eat less to get the same amount of carbs as you would with cream of wheat. If you have diabetes, then you will definitely want to choose cream of wheat over white rice.
You may have also noticed from the chart that broccoli has a glycemic index of zero as well as a glycemic load of zero. You may be thinking that this indicates it is a great source of carbohydrates. What it really means is that the carbohydrates in broccoli are all fibre, that there is no useful carbohydrate in broccoli, and it will have no effect on your blood sugar levels for that reason. Beware of carbohydrate sources with very low glycemic levels and very low glycemic loads... it can mean that the carbohydrates contained within it are not used by the system, which is why they have little effect on blood sugar. Dividing the glycemic load by the glycemic index will give you the amount of carbohydrate by weight.
So… what have we figured out? It would be beneficial to take the glycemic index, glycemic load and the carbohydrate per weight all into consideration when eating your carbs. Then, when you compare two sources, you will know how fast each carbohydrate source will raise your blood sugar, and you will know how many calories of each you will need to eat in order to get the same amount of carbohydrates. This will make all of your decisions much more accurate, thus making your diet much more effective. In addition, when someone is recommending what types of carbohydrates to eat, you will be able to scrutinize the information much better and make your own decision on what is best for you.