Simple and Complex Sugars


Sugar is a general name for a carbohydrate produced by plants using photosynthesis. The types of sugar that are most common to us are glucose and fructose, which we can get from the food we eat. Alone, these sugars are called simple sugars. As a chain of sugars, they are called complex carbohydrates.

Simple sugars are monosaccharides and disaccharides. Monosaccharides are one molecule of sugar and disaccharides are two sugar molecules linked together. The sugar we use every day is sucrose, which is a disaccharide made up of glucose and fructose. 1 teaspoon of sugar contains 4 grams of sucrose and is about 15 calories.

Complex sugars are oligosaccharides and polysaccharides. Oligosaccharides contain 3 or 4 to 9 or 10 sugars linked together. Polysaccharides are 10 or more sugars linked together.


Simple sugars

These sugars are monosaccarides or disaccarides. These monosaccarides are glucose, fructose, galactose. All of these sugars have the same atomic make up but have slightly different shapes. This means that they are isomers of each other. They are high energy, high calorie

Glucose is the most basic of all sugars because it’s the main source of fuel for our bodies. All our cells use glucose as energy by breaking it down into carbon dioxide. We break down glucose by essentially stripping it of electrons during cellular respiration to make ATP (Adenosine triphosphate), which is a molecule that powers many things in our cells.

Our body stores glucose as glycogen, which is a very large polysaccharide chain made of glucose molecules. It looks much like a starch molecule. Our liver and muscle cells store glycogen to use when we don’t get enough glucose or for when we exercise.


Fructose is a sugar that’s virtually identical to glucose. Their molecular structures are slightly different but this slight change makes all the difference in sweetness. Glucose is sweet but fructose is super sweet and tastes sweeter than honey. In fact honey is made primarily of fructose. Our bodies also convert glucose into fructose before breaking it down into carbon dioxide.

High Fructose Corn Syrup

High fructose corn syrup (HFCS) is made from corn starch.  Enzymes are used to convert the glucose into fructose. The resulting solution can be purified even more to get really high concentrations of fructose to use as a sweetener in processed foods. The corn syrup that’s produced is cheaper than the corn that was used to make it. Since it’s so cheap, this sugar is an ingredient in processed foods like sodas, fruit juices, syrup, and in less obvious sources like pasta sauce and breads.


Lactose is one of the more popular disaccharides and it’s made up of one glucose molecule and one galactose molecule. A specific enzyme is required to break down lactose into glucose and galactose and most humans begin to naturally lose this ability within a few years after being weaned however, some may keep on producing lactase into their adult years. Why some people keep producing lactase as adults may be due to diet, genetics or a combination of both as well as other factors.





Oligosaccharides are naturally found in vegetables like onions, carrots and cruciferous vegetables. These sugars are also involved in identifying different blood types. They are found in the form of fructo-oligosaccharides (FOS) in food. They generally exist as fibers that can get broken down to smaller chains when they are exposed to heat. So, when you cook certain vegetables they get sweeter. For example, roasting cruciferous vegetables or carrots causes them to taste sweeter. The caramelizing of onions is, in part from these oligosaccharide chains breaking down.





Polysaccharides are long chains of sugars naturally found in foods like grains and are called starches. These polysaccharides are called Complex carbohydrates (Complex carbs) and they are also made up of certain types of fiber. An example of complex carbs are amylose and amylopectin. Both of these large molecules make up starch, which are found in foods like rice, potatoes, corn, wheat and other whole grains and vegetables. Arrowroot is another example of a starch. Pectins are also polysaccharides that are used as gelling agents, thickeners and stabilizers in food. It’s what gives jelly or jams their gel-like character. Starch chains extend on for hundreds and possibly thousands of molecules of sugar in order to make one molecule of starch.




So which sugar is better?

All of these sugars are ok to eat in moderate amounts. However, polysaccharides are best for our health because they take longer to break down into glucose. This lag time means that we don’t get huge spikes in our blood sugar or insulin levels. It also means we are less likely to experience a burst of energy followed by a crash in energy levels. Complex carbs “feed” your cells little by little instead of all at once. Studies are showing that High fructose corn syrup does not contribute more to obesity, diabetes and cardiovascular disease than regular sugar (sucrose), but, the key point is that they do contribute to diabetes, obesity and cardiovascular disease. And, because these sugars are found in most of our foods, we can easily get way too much of it on a daily basis. Simple sugars are found everywhere as a sweetener in virtually all packaged foods so its best to avoid them and stick to fruits and vegetables, which contain polysaccharides and fibers that don’t cause your sugar and insulin levels to spike.

As a general guideline, when you do your food shopping stick to the outside aisles where you’ll find the fruits, vegetables, meats, and dairy foods. Stores tend to keep packaged products in the center aisles. By doing most of your shopping along the edges of the store, you’ll avoid most of the food products that contain simple sugars.


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