Blood sugar or blood glucose measurements represent the amount of sugar being transported in the blood during one instant. The sugar comes from the food we eat. The human body regulates blood glucose levels so that they are neither too high nor too low. The blood's internal environment must remain stable for the body to function. This balance is known as homeostasis. The sugar in the blood is not the same as sucrose, the sugar in the sugar bowl. There are different kinds of sugar. Sugar in the blood is known as glucose. Blood glucose levels change throughout the day. After eating, levels rise and then settle down after about an hour. They are at their lowest point before the first meal of the day, which is normally breakfast.