Fructose, Glucose, And Sucrose: The Difference And Effects

Along with salty foods, sweet foods are probably the most frequently consumed foods. Even spicy foods rank lower when compared with sweet foods in the Western diet. We consume all types of sugar without knowing the difference between them or what each one does to our body. Let’s “break down the sugars” and find out some interesting facts.

All sugars are a source of energy, but there are subtle differences in the way they are digested and absorbed. Though the tongue can’t tell the difference between these sugars, your body certainly can. They all give you similar amounts of energy per gram but are assimilated and utilized differently throughout the body.


Simple sugars, which are a form of carbohydrate, are of two types – monosaccharides and disaccharides.


Monosaccharides are simple sugar molecules that need the least effort by the body to assimilate and dispense energy more quickly than disaccharides. Glucose, fructose, and galactose are all monosaccharides. Monosaccharides don’t require any digestion and are absorbed into the mouth.



Glucose is found in pasta, legumes, and most vegetables

Glucose, found in whole grain bread, pasta, legumes and most vegetables, is the body’s main source of energy. It is also called blood sugar, as it circulates in the blood, and depends on the enzymes glucokinase or hexokinase to initiate metabolism.


The body converts most carbohydrates we consume into glucose, which is used immediately for energy or stored in muscle cells or the liver as glycogen for later use. For efficient absorption of glucose, the cells require insulin, which is secreted mainly in response to elevated blood concentrations of glucose.


Fructose is found in honey, fruits, and soft drinks


Fructose is a fruit sugar found naturally in fruits, honey, some vegetables, soft drinks, and beverages such as soda and fruit-flavored drinks. It is very different from other sugars as it has a different metabolic pathway and is not the preferred source of energy for muscles or the brain.

Fructose is only metabolized in the liver and relies on fructokinase to initiate metabolism. It is also more lipogenic, or fat-producing, than glucose. Unlike glucose, it does not trigger the release of insulin or stimulate the production of leptin, a key hormone for regulating energy intake and expenditure. Since fructose appears to behave more like fat in the body than like other carbohydrates, it raises concerns over chronically high intakes of dietary fructose.



Galactose is found in dairy products, legumes, and dried figs

Galactose, less sweet than glucose and fructose, is a component of lactose and is found in dairy products, legumes, and dried figs.



Just like monosaccharides, disaccharides too mostly break down in the mouth, depending on the oral bacteria in the mouth. But most of the digestion occurs in the small intestine.


Sucrose is also called as table sugar and is found in sugarcane, sugar beets and some fruits


Sucrose, commonly called as table sugar, is made of two simple sugar molecules – a glucose molecule and a fructose molecule – and is found in sugarcane, sugar beets, some fruits and vegetables, and sweetened products such as ice cream, cereal, baked desserts, and yogurt.

When consumed, sucrose is broken down into its individual sugar units of glucose and fructose, which are then taken up by their specific transport mechanisms. While glucose is used by the body as its main energy source, the excess energy from fructose goes into fat synthesis, which is stimulated by the insulin released in response to glucose.


Lactose is found in dairy products

Lactose, often called as milk sugar, is made of glucose and galactose. Lactose is mainly found in dairy products and is added to baked foods, cereals, lollies, and processed foods.


Maltose is usually found in malted milkshakes and beer

Maltose is also called as malt sugar and is composed of two glucose molecules. It is found in cereals containing barley and malt products like malted milkshakes, lollies, and beer.

Health Effects

Fructose And Metabolic Syndrome

Fructose may increase the uric acid in the body

One study found that fructose may increase uric acid in your blood and is linked to metabolic syndrome1, a combination of medical problems that increase your risk of cardiovascular disease and diabetes when they occur together.

Reducing added sugars in your diet is the best way to decrease your risk of metabolic syndrome. Fruits, vegetables, grains, and milk do not contain added sugars. Consume fresh foods and limit your consumption of processed foods.

Glucose Fares Better

Glucose does not increase triglycerides as much as other sweeteners that have fructose

A study that compared the effects on monkeys from consuming beverages sweetened with fructose, glucose, sucrose and high-fructose corn syrup (HFCS) found that glucose did not increase triglycerides (fats or lipids in your blood) as much as the other sweeteners that contain fructose.

Another study found that beverages sweetened with fructose or HFCS increased blood lipids in adult humans in just two weeks, where as beverages sweetened with glucose did not.

What To Consume And What To Avoid

Avoid foods that contain added sugars

Sugars that should be consumed the least are sugar-sweetened beverages (soft drinks, flavored mineral water, and energy drinks). Consider consuming fruits, which are the best source of dietary fiber, vitamins, and minerals.

All added sugars are devoid of vitamins, minerals, and dietary fiber. All sugars contribute unwanted calories in most people and except lactose, which is the least likely to break down in the mouth, all sugars can cause dental caries.

Weight gain and dental caries are two main reasons why the WHO recommends adults and children reduce their daily intake of “free” or “added sugars”, usually found in soft drinks and confectionery, to less than 10 percent of their total energy intake.