The standard healthy blood sugar levels are between 60 and 100 milligrams per deciliter of blood, states WebMD. Although, healthy blood sugar levels can reach up to 140 milligrams per deciliter of blood for 2 hours after eating. Healthy people are usually well below the limit.
Blood sugar levels are lowest prior to meals, usually between 70 and 80 milligrams per deciliter of blood for most people, claims WebMD. Blood sugar levels for most people do not go below 60 milligrams per deciliter of blood absent of medical problems. High blood sugar levels can lead to pancreas cells losing the ability to create insulin. In addition, excess sugar in the blood can lead to the hardening of blood vessels called atherosclerosis.