Why Are Fasting Blood Glucose Numbers High?

If you have high fasting blood glucose numbers, it may be because of how your body is using the hormones involved with glucose and diabetes -- not the nighttime snack before bed. Read on to see what can cause high morning blood sugars.


How the Essential Hormones Work in the Body

When diabetes is not present, the body handles the changing supply of and demand for glucose (the energy from food) 24 hours a day. This system involves the four hormones -- what we'll call the messengers -- and a continuous feedback loop that moves messages between the brain, gut, pancreas, and liver.

Here's how the system works in people without diabetes:

When fasting: As blood glucose falls after peaking from the last food eaten, the pancreas puts out less insulin hormone. At the same time, two other hormones wane: amylin and glucagon-like peptide 1 (GLP-1), which help store and use glucose. A fourth hormone, glucagon, kicks into gear to offer a constant flow of glucose. Glucagon sends messages to the liver and muscles to make glucose from stored energy.

After eating: Food raises blood glucose and sends a message to the intestines to release GLP-1, which primes the insulin and amylin spigots. These hormones help cells use the glucose from food to fuel the body. The glucagon spigot turns off because there's little need for glucose from the liver or muscles when food is available. The impact of food on blood glucose, even for a large, high-fat meal, lasts less than six hours.