Sugar is a simple carbohydrate that provides most of the energy the body needs to function. Dietary sugar comes in many forms and from many sources, including fruits, milk, other foods and some medications. After they are consumed, these sugars are converted into glucose (blood sugar), which a hormone called insulin allows the cells to use for fuel.

With diabetes, excess glucose builds up in the bloodstream. This hyperglycemia occurs because the body either can no longer make or properly use insulin.

Some research has suggested that heavy consumption of sugar may help cause type 2 diabetes. Yet organizations such as the American Diabetes Association state that eating sugar does not cause diabetes. Rather, a diet high in calories promotes obesity, a major risk factor for diabetes.

For many years, people with diabetes were urged to drastically reduce or eliminate sugar from their diet to ensure control of blood glucose levels. However, recent research has revealed that all carbohydrates affect blood glucose levels – a potato and a candy bar with the same amount of carbohydrates can cause a similar rise in glucose.

This finding does not mean sugar has the same effect on health as other foods. Sugary foods contain more carbohydrates per serving size and fewer vitamins and other nutrients than many other foods. They also usually lack fiber, which moderates levels of glucose and cholesterol. Some people also fault sugary foods for having a high glycemic index, but that system of ranking foods according to their effect on glucose is controversial.

People with diabetes can use artificial sweeteners (sugar substitutes) to sweeten their foods without causing hyperglycemia. Some of these sweeteners, however, do contain calories and carbohydrates that can raise glucose when consumed in large amounts.

Physicians often recommend that diabetic patients carry sugar or a sugary food with them and consume a specified amount to treat episodes of hypoglycemia (low blood glucose).