What is glucose?

John A. Chabot
Endocrinology Diabetes & Metabolism
Glucose is a simple sugar that is used by the body as a source of energy and a metabolic intermediate.

Glucose is a simple form of sugar that serves as fuel for the body. It is produced when carbohydrate is broken down in the digestive system. It can also be made from protein or fat in the liver and kidney. Glucose is carried by the blood to cells. The amount of glucose in the blood is known as the blood glucose level.

Emilia Klapp
Nutrition & Dietetics
Glucose is the fuel that most tissues in your body use. It is the only fuel your brain can use. The glucose in your body comes from three major nutrients: protein, fat, and carbohydrates. About 50% of the protein, 10% percent of the fat, and nearly 100% of the carbohydrates you eat are broken down into glucose by digestive enzymes in the mouth and intestines. Glucose then travels through the bloodstream with the help of hormones, such as insulin, that are produced by the pancreas.
William Lee Dubois
Endocrinology Diabetes & Metabolism
Glucose is a simple sugar that is the basic fuel for the body. The job of the digestive system is to convert all that you eat into glucose so that cells can use it for energy. From Twinkies to T-bones, all that you eat becomes glucose to feed your hungry cells.
Beyond Fingersticks: The art of control with continuous glucose monitoring

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Beyond Fingersticks: The art of control with continuous glucose monitoring

Everything you ever wanted to know about CGM (but didn’t know to ask)!Continuous Glucose Monitoring (CGM), the revolutionary technology that’s poised to completely change diabetes care, gives you...

Glucose is the energy source that the body most readily uses. Glucose is sugar that is stored in the muscle for use. If it is not used it will be converted and stored as fat.

Glucose is a simple sugar molecule that initiates metabolism and can be converted easily for energy. Because it is of a single molecule and doesn’t need to be broken down like more complex sugars, it easily and quickly enters the bloodstream and used for energy. However, the body does not store glucose, and converts it to glycogen to either be stored in the liver or muscle tissue. If the body has a sudden need, the glycogen can be converted back to glucose for immediate fuel. When large quantities of simple carbohydrates or sugars are ingested from certain foods, there will be a sudden spike in insulin levels that leads to the uptake of any available glucose. This leads to a sudden boost of energy, known by many as a “sugar high”, but is followed by a feeling of fatigue and tiredness due to the sudden drop in insulin levels.  
Healthy Humans
One of the most amazing facts of biology is that all cells are built from the same building blocks. Whether it is bacteria or an ant, algae or a tree, a crab or a fish, a dog, a cat or even a human being, all living things have the same chemical building blocks from the same four categories: proteins, carbohydrates, fats, and nucleic acids. All of these chemical building blocks are long chains of smaller simpler molecules. Carbohydrates are one such chain of simpler molecules called sugars, and glucose is a sugar.

There are many common sugars in our diet. The sugar in fruit is fructose. Lactose is the sugar found in cow's milk. Table sugar is sucrose, a type of sugar called a disaccharide, which means it is composed of two simpler sugars: fructose and glucose. The main function of sugar in its simplest form is to supply a ready source of energy for the cell. Our bodies have evolved a very close relationship to sugar, and we know its taste intuitively as something we like. This is because to our ancestors, the taste of sugar was a sign that something was good for us. It meant that the food we were tasting was full of nutrition and energy. In its naturally occurring form, sugar is typically accompanied by fiber as it occurs in fruit and certain sweet vegetables. The problem with our modern diet is that sugar now is a signal for highly refined foods,usually low in fiber and often with very high and unnatural amounts of sugar. We're tricking our bodies and ourselves. We (or the food industry) have taken a naturally occurring food (sugar) that we've had 40,000 years of evolution to get to know and like in its natural state, and turned it into something very toxic.

Continue Learning about Carbohydrates


Starches, sugars and fiber are the carbohydrates in food. Carbohydrates are a molecule that plants make during photosynthesis, combining carbon, hydrogen and oxygen. They are very important in your body's metabolism because they a...

re generally the part of food that is digested most quickly. Carbohydrates can give you quick energy, and cause a rise in blood sugar levels. Diabetics, in particular, need to pay attention to the carbohydrates they eat to help manage their blood sugar. Some carbohydrates, those found in whole grains and leafy vegetables, for example have a much slower impact on blood sugar than carbohydrates in fruits or candy. It's easy to consume a lot of carbohydrates, as foods like breads, pasta, cake, cookies and potatoes are loaded with them. Nutrition experts suggest that you should only get 45 to 65 percent of your daily nutrition from carbohydrates.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.