Fasting blood sugar: Normal levels and testing
Fasting blood sugar provides vital clues about how the body is managing blood sugar levels. Blood sugar tends to peak about an hour after eating, and declines after that.
High fasting blood sugar levels point to insulin resistance or diabetes. Abnormally low fasting blood sugar could be due to diabetes medications.
Knowing when to test and what to look for can help keep people with, or at risk of, diabetes healthy.
What are fasting blood sugar levels?
Following a meal, blood sugar levels rise, usually peaking about an hour after eating.
How much blood sugar rises by and the precise timing of the peak depends on diet. Large meals tend to trigger larger blood sugar rises. High-sugar carbohydrates, such as bread and sweetened snacks, also cause more significant blood sugar swings.
Normally, as blood sugar rises, the pancreas releases insulin. Insulin lowers blood sugar, breaking it down so that the body can use it for energy or store it for later.
However, people who have diabetes have difficulties with insulin in the following ways:
People with type 1 diabetes do not produce enough insulin because the body attacks insulin-producing cells.
People with type 2 diabetes do not respond well to insulin and, later, may not make enough insulin.
In both cases, the result is the same: elevated blood sugar levels and difficulties using sugar.
This means that fasting blood sugar depends on three factors:
the contents of the last meal
the size of the last meal
the body's ability to produce and respond to insulin
Blood sugar levels in between meals offer a window into how the body manages Continue reading