Sugar Science: What Are the Different Forms of Sugar?

Eleanor King

When people think of sugar, they often think about the small white crystals used in cooking and baking. While this is a type of sugar, known as sucrose, it is just one of many forms that make up what is considered “sugar.” 

Sugars are a type of carbohydrate that provide the body with energy when digested and broken down. Humans are naturally born with a “sweet tooth” to ensure that breast milk is palatable and enjoyable for infants. While many forms of sugar are naturally forming, such as those found in breast milk, there are many other forms of sugar that have been processed and refined. Regardless of their source, all forms of sugar provide roughly 4 calories per gram, similar to that of other carbohydrates.

We’ve broken down four common forms of sugar you consume and what you should know about them.

Sucrose


This form of sugar is found in sugar beets and sugarcane, and is extracted and refined for human consumption. It is a naturally occurring sugar which after refinement is used in many processed foods. Up until the 18th century, refined sugar was a luxury good due to the long refining process. Since it’s refined, it is composed of 99.9% sucrose and provides only carbohydrates as a nutrient. There are no macronutrients in fully refined sugar. The most common form of sucrose is white table sugar, also known as granulated sugar. 

Fructose


Most commonly found in fruits, honey, and root vegetables, fructose is another plant-derived form of sugar that is often bonded with glucose. The most common reference to fructose is high-fructose corn syrup, a notoriously unhealthy and overused sweetener in processed foods. While this is not a pure form of fructose, is it a main way the average person consumes fructose. Pure fructose only provides carbohydrates as a nutrient and contains no other macronutrients. Fructose is the sweetest form of naturally occurring carbohydrates.

Glucose


This form of sugar is important for all life as it is what gives most living things their energy. In humans and animals, it circulates in the bloodstream as blood sugar, a vital part of the body’s ability to function. It is a naturally occurring sugar that can be found in honey, fruits, and vegetables. People who have blood sugar–related illnesses, such as diabetes, have issues regulating their glucose levels and often carry small amounts of glucose in various forms. In most processed foods, glucose bonds with fructose to create new forms, such as high-fructose corn syrup. 

Lactose


Found in milk, lactose is a commonly known sugar because of its connection to lactose intolerance. It makes up about 2%–8% of milk, depending on the maturity of the animal producing it. Lactose can help the body absorb minerals and act as dietary fiber when not completely digested. Those who are lactose intolerant are unable to break down the lactose sugar, which can lead to gastrointestinal issues. Lactose is not a very sweet sugar, but it is used in a variety of applications, including in the pharmaceutical industry where it is used in tablets and capsules. 

There are several other forms of sugar that typically form through the combination of two of the above forms. These include maltose, galactose, and trehalose. Currently, the Dietary Guidelines for Americans recommends a consumption of less than 10% of daily calories from sugar.