Due to their molecular structure carbohydrates are divided into the so called simple and complex carbohydrates.
The simple carbohydrates are the so called monosaccharides (simple sugars like e. g. glucose and fructose) and disaccharides (double sugars like e. g. refined sugar crystals, malt sugar or lactose).
In opposition to the simple mono- and disaccharides the complex carbohydrates include all types of sugar (saccharides) that contain at least three monosaccharide molecules.
These are e. g. oligosaccharides (multiple sugars like e. g. raffinose (raffinose is a carbohydrate contained in plants, to be exact a triple sugar (trisaccharide)) as well as polysaccharides (multiple sugars like e. g. starch, cellulose, chitin).
As far as possible we should avoid simple carbohydrates that can be found mostly in sugar, sweets, honey and some fruits. Simple carbohydrates have the trait to increase the blood sugar level at a very fast pace and thus cause a high release of insulin and arouse the sensation of hunger!
Complex carbohydrates saturate longer and supply all kinds of important substances for our health. They contain many vitamins and are high in dietary fibres. Complex carbohydrates can be found in vegetables, grains, potatoes and leguminous plants.
The amount of carbohydrates in our diet should predominantly consist of complex carbohydrates. As they have to be broken down in the small intestine they are transferred into the blood at a slower but more continuous pace. Thus a constant blood sugar level is achieved for a longer amount of time. In this way a consistent supply with energy over a longer time is made possible. Moreover important vitamins, minerals and dietary fibres are delivered together with these carbohydrates. The organism has to spend energy to utilise long-chain carbohydrates, a process similar to the digestion of proteins.
The simple sugars (mono- and disaccharides) are turned into glucose quicker and arrive in the blood in a shorter amount of time. They let the blood sugar level rise quickly and increase the release of insulin. More insulin means a higher breakdown of glucose, a decrease of the blood sugar level and a renewed sensation of hunger.
Therefore you should consume few simple carbohydrates and better help yourself with complex carbohydrates. Superfluous carbohydrates are not discarded but stored in the liver and the muscles as a quickly utilisable body’s own energy supply. Under certain circumstances surplus glucose can be transferred into fat. Thus when feeding on a diet very rich in carbohydrates (more than 500 g sugar per day) the well known fat stores can develop even if the diet is poor in fat.