Glucose is a simple sugar, and is very prevalent in many foods. In fact, it is the main way plants store energy, mostly as starch, which is made up of long strings of glucose.
Almost all the starches we eat (potatoes, grains, flour, etc.) is primarily composed of glucose. In addition, glucose exists as a sugar in some foods, mainly fruits and some vegetables. Added sugars such as table sugar, honey, and high fructose corn syrup are about half glucose and half fructose.
Our bodies use glucose for energy, although our capacity to store it is limited, and the extra gets turned to fat (which is our main energy storage). Glucose is circulating in our blood at all times, and our bodies have mechanisms to keep the amount of glucose in our blood (about 5-7 teaspoons at any one time) controlled within a narrow range. If we have too little glucose in our blood, this is called hypoglycemia.
Increasingly, people’s bodies are having more trouble controlling their blood glucose.
If it gets too bad, it diagnosed as diabetes. Before that point, there is a spectrum of difficulties with blood glucose, including prediabetes, metabolic syndrome, and insulin resistance.
Since most of the carbohydrate we eat turns to glucose in our bodies, lowering the amount of carbohydrate consumed can help with these disorders of glucose metabolism.