In the field of sports nutrition, few nutrients are as controversial as carbohydrates. In the past, any kind of fats were avoided and considered harmful; today carbohydrates have been declared the enemy. For many it has become a dogma to eat none, or very few; others do not eat certain types. As with fats, however, we need to take a closer look: Just because a particular type of carbohydrate may affect your health, fitness, and appearance, this doesn’t mean all carbohydrates are bad.
As a Free Athlete, it is important to understand what carbohydrates are, what they are made up of, and what tasks they perform. Only those who know the basics about carbohydrates can form an opinion and decide whether to eat them, and if so, which types and in what amount.
What are carbohydrates and what are their building blocks?
Essentially, carbohydrates always consist of individual sugar molecules (monosaccharides). These are organic compounds created by combining carbon dioxide with water under the influence of sunlight in the process of photosynthesis. These sugar molecules are the simplest and most basic form of carbohydrates. At the same time, they form the basis for all other carbohydrates, which are composed of multiple sugar molecules of the same or a different kind.
Depending on the number of sugar molecules – which form bonds with each other – carbohydrates are known as single, double (disaccharide), and multiple sugars (oligo- or polysaccharides). In current language, we therefore make the distinction between simple and complex, or short-chain and long-chain carbohydrates.
Similar to fats, monosaccharides consist in their basic structure of a carbon chain – to which hydrogen and oxygen atoms are connected – and are mainly intended for energy storage and generation. The best known monosaccharides are glucose (also called dextrose), fructose (fruit sugar) and galactose. With 17.2 kJ (4.1 kilocalories) per gram, the energy content of carbohydrates is, however, more than 50 percent lower than that of fats and is similar in energy content to proteins.
What happens to carbohydrates in the body?
The body metabolizes carbohydrates into pure energy. To achieve this, the body keeps splitting or converting carbohydrates until they turn into glucose, which is the most easily usable source of energy for our body. Glucose is ingested via the intestine wall and delivered into the bloodstream, from where it is carried to the cells, which in turn use it for the generation of energy. The primary user of this energy is the brain, which uses about half of our your glucose intake. The other half is required by the kidneys and red blood cells. The muscles also help themselves to this simple source of energy – if it is available.
To bridge the time between meals or long periods of fasting (e.g., sleep), as well as to ensure sufficient supply during periods of increased physical stress, our body also stores glucose in the form of glycogen in the liver, renal medulla and the muscles. Glycogen consists of long chains of glucose building blocks which can be quickly disassembled and used. The body has limited storage for glycogen, and acute needs may not occur frequently enough. Surpluses are therefore converted into body fat, because we can – in theory – store fat unlimitedly and, if necessary, create new storage locations.
Why are carbohydrates so controversial?
The body always keeps the amount of free glucose in the blood – also known as blood sugar levels – within a narrow range. If there is too little glucose in the blood, weakness, fatigue andhunger can set in, as well as difficulties in concentrating.
Meanwhile, excessive blood sugar levels cancause red blood cells to agglutinate (stick together), which is why the body works hard to process excess glucose as quickly as possible. To facilitate this, the pancreas immediately releases insulin, a hormone which picks up the sugar from the blood and signals to the cells to absorb nutrients.
In particular, the blood sugar levels rise rapidly with the intake of simple carbohydrates, because these carbohydrates are immediately and at once secreted into the bloodstream. Our body reacts almost in a panic, pouring out large amounts of insulin. This has two disadvantages: First, blood sugar levels then decrease to a very low level so that we feel hungry even though enough energy is available. Second, the cells are quickly saturated so that the glucose collected from the blood is generally not used and, as a result, converted into fat in the liver.
The more complex the type of carbohydrate absorbed, the longer the body takes to break down and release glucose into the blood. Consequently energy supply is constant, without blood sugar levels showing large swings up or down.
Some carbohydrates are so complex that the body cannot break them down. As a result, they are not metabolized. They are commonly known as dietary fiber. These are essential for intestinal health, the digestive system, and the regulation of blood glucose levels as they slow down the breakdown of their recyclable colleagues.
The simpler the absorbed type of carbohydrate and the larger the amount, the faster and higher blood sugar levels will increase. In times when we need energy fast and in large amounts, this can be extremely useful and desirable. Compared to the energy actually used, today’s dietary choices offer a large surplus of simple carbohydrates, which suddenly enter the bloodstream. The most famous among them are almost all types of sugar, as well as products with white flour, which have been deprived of all valuable nutrients and dietary fiber.
There are also carbohydrates which can be extremely useful. Which ones, how many, what foods contain them, and how they are used, you will soon learn in this series about carbohydrates.