What is High Glucose?

Fasting blood glucose is part of a routine blood test. What does it mean if your fasting glucose is high? Learn what to do to lower fasting glucose.

Monica Reinagel, MS, LD/N, CNS
5-minute read
Episode #113

If you’ve ever had a blood test where they asked you not to eat for twelve hours beforehand, then they were probably testing your fasting blood glucose level.   This week, I got an email from a reader who’d recently had such a test and found out that her fasting glucose was too high. She’s wondering exactly what that means and what—if anything—she should do about it.

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What Does Glucose Do?

It’s normal to have a certain amount of glucose—or sugar—in your blood. It’s there because it’s on its way to your cells where it will be converted into the energy that powers all of your body’s functions. No glucose = no energy = no life.

It’s also normal for your blood sugar to rise after you eat. Blood sugar levels go up as the food you’ve eaten is digested and converted into glucose. Then, as that glucose is taken up by your cells, blood sugar levels fall back to baseline. At least they’re supposed to.

Doctors test your glucose after you haven’t eaten for eight to twelve hours in order to see where your baseline is. If your fasting glucose levels are high, it’s sort of like having an elevator that only comes down to the fifth floor instead of returning all the way to the ground floor.

What Is High Glucose and Why Does It Matter?

Fasting glucose readings in the high-normal range—while they’re not an emergency—are considered an early warning sign that you may be headed for trouble.

Although there are a few different things that can cause high fasting glucose, this test is usually done to screen for diabetes. If your glucose levels are really high, your doctor will probably order additional tests to confirm a diagnosis and begin treatment. Readings in the high-normal range—while they’re not an emergency—are considered an early warning sign that you may be headed in that direction. Consider it a wake-up call. And I don’t recommend that you hit the “snooze” button.

The House Call Doc has a great description of exactly what Type 2 diabetes is and why it’s definitely something you want to avoid.


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.