What to know about fasting blood sugar?
Fasting blood sugar levels give vital clues about how a person’s body is managing blood sugar. 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, while abnormally low fasting blood sugar could be due to diabetes medications. Knowing when to test and what to look for can help keep people stay healthy, especially if they have diabetes or are at risk of developing the condition.
Fasting blood sugar levels
The body needs glucose for energy, and glucose comes from the food we eat. However, the body does not use all of this energy at once. Insulin makes it possible to store and release it as necessary. Following a meal, blood sugar levels rise, usually peaking about an hour after eating. How high blood sugar rises, and the precise timing of the peak depends on the person’s diet. Factors relating to food that can trigger significant rises include:
- eating large meals
- consuming glucose rich foods and drinks
- eating foods with simple carbohydrates, or carbs, such as bread and sweet snacks
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 one of two ways:
- Those with type 1 diabetes do not produce enough insulin because their body attacks its insulin-producing cells.
- Those with type 2 diabetes do not respond well to insulin in their body and, later, may not make enough insulin.
In both cases, the result is the same, with people experiencing high blood sugar levels and difficulty using glucose, or blood sugar.
This means that fasting blood sugar depends on three factors:
- the contents of a person’s last meal
- the size of their previous meal
- their body’s ability to produce and respond to insulin
Blood sugar levels between meals offer a window into how the body manages sugar. High levels of fasting blood sugar suggest that the body has been unable to lower the levels of sugar in the blood. This points to either insulin resistance or inadequate insulin production and, in some cases, both.