What is Prediabetes and Why is it Important?

Blog Post

Stephen W. Farrell, PhD, FACSM
The Cooper Team
November 7, 2022

If you are a Cooper Institute follower, then you are probably aware that cardiovascular disease (CVD) is the leading cause of death in all developed countries. You may also know that having diabetes increases the risk of heart attack and stroke by approximately three-fold and that rates of diabetes have been climbing steadily over the past several decades. In fact, it is estimated that 37 million Americans (11% of the population) are currently living with diabetes. Approximately 95% of these individuals have type 2 diabetes, which was formerly called adult-onset diabetes. Although the most common method for diagnosing diabetes is with a fasting blood glucose measurement, other blood measures such as a random blood glucose test, oral glucose tolerance test, or Hemoglobin A-1C test are also used. When fasting blood glucose is used as the criterion for diagnosing diabetes, a level greater than 125 mg/dL on two separate occasions indicates the presence of this condition. As a point of reference, a normal fasting blood glucose level is between 60 and 99 mg/dL.

You may not have heard as much about prediabetes. This is a very common condition where the fasting blood glucose level is between 100-125 mg/dL on two separate occasions. Prediabetes is an important risk factor for CVD, and it is currently estimated that 96 million Americans are living with prediabetes. So, when we put all the numbers together, nearly 40% of the U.S. population has diabetes or prediabetes!

The Table below summarizes the three categories for fasting blood glucose categories.

Fasting Blood Glucose Categories:

Normal: 60-99 mg/dL

Prediabetes: 100-125 mg/dL on two separate occasions

Diabetes: >125 mg/dL on two separate occasions

The best way to think about prediabetes is as a condition where the fasting blood glucose level is higher than normal, but not high enough to be diabetes. Prediabetes is a significant condition not only because it places the individual at greater risk for CVD, but also because a substantial number of individuals with prediabetes go on to develop full-blown type 2 diabetes within several years! Another issue of great concern is that many individuals with prediabetes are not even aware of their condition.

So why do 96 million Americans have prediabetes? Great question! While prediabetes is more common among older individuals and genetics is sometimes a factor, the vast majority of individuals with prediabetes are either overweight and/or do not perform sufficient amounts of regular physical activity. Consuming an unhealthy diet can also be part of the mix. It really is that simple! This doesn’t mean that you have to look like a swimsuit model and exercise for hours each day to prevent prediabetes. In fact, moderate weight loss and meeting the most recent physical activity guidelines can go a long way towards preventing or even reversing prediabetes.

Let’s look at an example:

Charles is a 50 year-old male who is 5’9” and weighs 215 lbs. His fasting blood glucose level is 106 mg/dL, which places him in the prediabetes category. His body mass index (BMI) is 31.7 kg/m2, which places him in the obese category. He consumes a lot of junk food and performs very little regular physical activity. Charles decides to take action by making changes to his diet and physical activity level. He cuts back on empty calories (non-diet soda, chips, candy, pastry, cookies, alcohol, fried foods) as well as saturated fat, and begins to eat more plant-based foods. This results in a consumption of about 400 calories less per day than usual. He also begins a progressive brisk walking program as outlined below, as well as a strength training program 2 days a week.

Charles’ Walking Program

Week Days per Week
Minutes per Walk Total Minutes Walking per Week
Week 1 3 20 60
Week 2 3 25 75
Week 3 3 30 90
Week 4 3 35 105
Week 5 4 30 120
Week 6 4 35 140
Week 7 4 40 160
Week 8 4 45 180
Week 9 5 40 200
Week 10 5 45 225
Week 11 5 50 250
Week 12 5 55 275
Week 13 5 60 300
Week 14 and going forward Maintain Maintain Maintain

Notice that Charles did not begin his walking program by trying to meet the physical activity guidelines right away. He started slowly, and gradually increased the total minutes per week. By week 7, he was meeting the guideline for good health, and by week 13 he was meeting the guideline for weight loss.* He manages to lose 20 pounds during this period of time. His BMI is now 28.8 kg/m2, with a fasting blood glucose of 95 mg/dL. Charles has moved from the obese to the overweight category, and has also moved from prediabetes to the normal fasting blood glucose category. As a bonus, Charles also noticed a reduction in his resting blood pressure. So, while no magazines will be calling to ask Charles to be a swimsuit model anytime soon, he has made a very significant positive change in his health status!

*Current guidelines recommend at least 150 minutes per week of moderate-intensity aerobic activity and at least 2 days per week of strength training for good health. If weight loss is the goal, aim for a minimum of at least 300 minutes per week along with strength training at least 2 days per week.

Note: For adults, the normal BMI range is between 18.5 and 24.9 kg/m2. Overweight is a BMI between 25.0 and 29.9 kg/m2, while obesity is a BMI greater than 30 kg/m2.


American Diabetes Association (www.diabetes.org)
Centers for Disease Control and Prevention (www.cdc.gov)


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