Simple vs Complex Carbohydrates

Carbohydrates, proteins and fats make up the three primary macronutrients that are essential in every balanced diet. Proteins and fats may be responsible for body functions such as the production of tissue yet it is primarily the carbohydrates that provide calories necessary for the production of energy.  In fact, carbohydrates provide about 60 percent of the amount of energy required by the body, which is largely used for normal body functions such as digestion, heartbeat, breathing and movements.  Carbohydrate type is determined by their chemical structure and categorized as either a simple carbohydrate or a complex carbohydrate.

Simple Carbohydrates

Simple carbohydrates have a chemical structure that is composed of one or two simple sugars.  They’re normally refined sugars that have very little nutritional value for the body so we like to advise our patients to consume limited quantities.  Simple carbohydrates are digested by the body quickly because they have a very simple chemical structure as compared to complex carbohydrates, which take a bit longer to digest.

Simple carbohydrates are further categorized as either monosaccharides or disaccharides. Monosaccharides consist of only one sugar, examples of which include fructose and glucose. Disaccharides consist of two chemically-linked monosaccharides, such as lactose, maltose and sucrose.  Simple carbohydrates typically taste sweet and include common foods such as table sugar, most white flour products, honey, milk, yogurt, candy, chocolate, fruit, cake, soft drinks and packaged cereals.  

Complex Carbohydrates

Complex carbohydrates’ chemical structure is made up of three or more sugars, which like to link together to form a chain and are usually rich in fiber, vitamins and minerals.  Because they’re complex it takes them a bit longer to digest and they don't raise blood sugar levels as quickly as simple carbohydrates.  Complex carbohydrates are basically converted into the body's fuel and make a significant contribution to the body’s energy production.

Complex carbohydrates are also divided into two categories, oligosaccharides and polysaccharides.  Oligosaccharides are made up of a small number of monosaccharides, which cannot exceed 10.  They’re important to the absorption of certain minerals.  They also help with the formation of fatty acids.   Polysaccharides, on the other hand, are often made up of a large number of monosaccharides and disaccharides and include cellulose, glycogen and starch.  Complex carbohydrates are found in foods like vegetables, whole-meal bread and some cereals. Foods that contain complex carbohydrates include beans, spinach, broccoli, beans, zucchini and whole grains, among many others.

Simple carbohydrates may have a lower nutritional value than complex carbohydrates yet it’s sometimes confusing to differentiate simple from complex carbohydrates because complex ones contain certain aspects of simple ones.  Yet differentiating the two scientifically is not a problem since their chemical structures are clearly defined and can be distinguished by their nutritional properties.  

So how can one start to figure out which carbohydrate is good and which is bad? One easy way to start is to look at the label.  Fiber is listed as a carbohydrate but, as a rule, does not add to the undesirable, weight-gain effect of carbohydrates.  So, you can deduct the fiber content from the total carbs to see what is left.  Another very helpful tip is to look up the Glycemic Index (GI) of a food.  In general, the higher GI foods are less desirable from a weight loss perspective.  For example, bread has a GI of 72 and is a poor choice on a weight conscious diet. Broccoli has a GI of about 10 and is an excellent choice for losing or maintaining weight.

So watch what you eat and make a point of learning which carbohydrates are simple and which are complex.  You don’t have to give up all carbohydrates.  In fact, we need to consume carbohydrates in order to function properly.  Yet you can make a big difference in your health, especially your weight, if you limit your intake of simple carbohydrates.

By John DeCosmo, DO
06 Mar 2014