Do You Have Prediabetes? How to Tell & What You Can Do About It

Diabetes is not only one of the most common chronic conditions in the U.S., it's also the most expensive. Of every $4 spent on U.S. health care, $1 goes toward the care of people with diabetes, according to the Centers for Disease Control and Prevention.

That's why preventing type 2 diabetes — which accounts for the overwhelming majority of diabetes cases — is so important, not just for your wallet, but also for your long-term health and quality of life overall.

And for the more than 1 in 3 Americans who currently have prediabetes — the precursor to type 2 diabetes — prevention starts with effective blood sugar management now, long before the potential onset of diabetes, says Dr. Archana Sadhu, an endocrinologist at Houston Methodist.

"Prediabetes is a critical stage where people can really change the trajectory of their condition so it doesn't get worse, and people can still live a good, healthy and long life," says Dr. Sadhu. "That starts with screening at-risk patients and implementing interventions as early as possible if prediabetes exists."

Dr. Sadhu explains who should get screened for diabetes, what happens if the results come back abnormal and what a prediabetes diagnosis means for people moving forward.

What is prediabetes?

Prediabetes is a condition characterized by blood sugar levels that are higher than normal but not high enough for you to be diagnosed with type 2 diabetes.

Whereas diabetes has clear symptoms — including frequent urination, excessive thirst, blurry vision and tingling hands and feet — prediabetes has no obvious symptoms.

It's one reason why more than 80 percent of the nearly 100 million American adults with prediabetes don't know they have it. Unless you have your blood sugar tested, you otherwise wouldn't know.

"Prediabetes is basically the early stages of insulin resistance in which a person's glucose is slightly abnormal," says Dr. Sadhu. "If this process is left untreated, it will progress to type 2 diabetes."

Who should get screened for prediabetes and diabetes?

Since prediabetes has no obvious symptoms, screening helps to catch it early before it has the chance to develop into type 2 diabetes. But the question of who should get screened and when is an "evolving area" that Dr. Sadhu says is likely to change in the future.

"The general age to start diabetes screening was 45," says Dr. Sadhu. "Now it's dropped to 35, but age isn't everything. Whether you should get screened earlier and how often is going to depend on which risk factors you have, so it's really age in the context of all of these other potential risk factors."

According to the American Diabetes Association, people are at a higher risk for prediabetes and type 2 diabetes and should consider getting tested earlier than 35 if they:

• Have a BMI greater than 25 (23 in individuals of Asian ancestry)
• Have a first degree relative with diabetes
• Have a history of cardiovascular disease
• Have high blood pressure or are on blood pressure medication
• Have high cholesterol
• Have polycystic ovary syndrome (PCOS)
• Have conditions associated with insulin resistance, including darkened skin patches called acanthosis nigricans, skin tags or nonalcoholic fatty liver disease
• Are of a higher-risk race/ethnicity such as African American, Hispanic or Latino, Native American or Asian American
• Are physically active less than 3 times a week
• Were diagnosed with gestational diabetes mellitus (GDM) while pregnant
• Regularly take steroids (including inhalers), certain HIV medications or second-generation antipsychotics like aripiprazole (Abilify) or quetiapine (Seroquel)

But even those with a BMI lower than 25 (or 23) may still be at risk, says Dr. Sadhu, who notes that BMI "may not reflect a patient's metabolic risk as accurately" as central fat measurements, such as waist circumference or waist-to-height ratio. BMI can be misleading in different individuals based on body composition, especially in Asian populations who tend to have a higher proportion of belly fat compared to other ethnic groups, she adds.

A waist measurement exceeding 35 inches in women and 40 inches in men puts you at a higher risk of developing type 2 diabetes, according to the CDC.

Should you be diagnosed with prediabetes, you'll want to be retested yearly, if not sooner, and people who were diagnosed with gestational diabetes while pregnant will also want to be retested every one to three years.

What's your risk? Dr. Sadhu recommends people take the type 2 diabetes risk test on the American Diabetes Association website.

How do you know if you have prediabetes?

The only way to know if you have prediabetes is to have your blood sugar (glucose) tested. The two most common (and simple) tests are a fasting blood sugar test and an A1C test.

A fasting blood sugar test (also called fasting plasma glucose) measures the amount of sugar that's in the blood after at least 8 hours of having nothing to eat or drink except water. A test result below 100 mg/dL is considered normal, a result between 100 and 125 mg/dL is consistent with prediabetes and anything above 125 mg/dL is considered diabetes.

Whereas a fasting blood sugar test is like a snapshot in time, an A1C test measures your average blood sugar levels over the last two to three months and doesn't require fasting.

Whether diabetic or not, you've always got some sugar in your blood, and some of it permanently attaches itself to proteins in our red blood cells across their lifetime. Since red blood cells regenerate roughly every three months, A1C measures how much of that sugar has permanently bonded with the blood in our bodies as a percentage. The more sugar we have floating in our blood, the more it tends to link up with it, thereby increasing A1C levels.

An A1C of 5.6% or below is considered normal, 5.7% to 6.4% is considered prediabetes and anything above 6.5% is consistent with diabetes.

Any person with a blood sugar above 125 mg/dL or an A1C above 6.4% will need to be retested to confirm the diagnosis, says Dr. Sadhu.

(Related: 4 Reasons You Need a Primary Care Provider)

Is it possible to 'reverse' prediabetes?

As Dr. Sadhu mentions, prediabetes is the critical stage in which people have the power to change the trajectory of their condition, but whether you can effectively "reverse" prediabetes depends on what your definition of reversal actually means, she says.

"In terms of reversing prediabetes, can you normalize your glucose? Much more so in prediabetes than diabetes, so if your definition of 'reversal' is normalizing glucose, then yes," she says.

"But when you think about what causes prediabetes at the cellular level, at the cells that make insulin in the pancreas, by the time you get to the prediabetes stage, you've lost over 50 percent of your ability to make adequate amounts of insulin," says Dr. Sadhu. "Those cells unfortunately don't regenerate; you can't bring them back, but you still have a majority of function left to where you can still stay out of the diabetes range if you do the right things to help preserve the remaining cell function."

"In that sense, you cannot reverse what's happened to the pancreas and the cells that make insulin," she continues. "The 'rocket' has effectively launched, meaning there's no going back to full function, but you can keep your condition stable, even normal, and live a very healthy life with what's remaining."

Should prediabetes develop into diabetes, Dr. Sadhu says the pancreas at that point will have lost at least 70 to 80 percent or more of its function, which puts people at a higher risk of serious health complications.

In treating prediabetes, action and motivation are key

"If prediabetes exists, we focus on key lifestyle interventions like diet, exercise and weight management," says Dr. Sadhu. "In fact, exercise is as good as insulin in reducing blood sugar, so it's a natural way to take the load off your pancreas cells that are trying to make more insulin than they can."

"We also have medications that have been proven to prevent prediabetes from developing into diabetes," she adds. "A classic one is metformin, and there are some others as well."

Dr. Sadhu's recommendations are rooted in what the National Institute of Diabetes and Digestive and Kidney Diseases says changed the way people approach type 2 diabetes prevention worldwide: the Diabetes Prevention Program (DPP), a large-scale trial involving more than 3,000 people at high risk for diabetes.

The study revealed that the most effective way to prevent or delay type 2 diabetes across all age groups, risk levels and ethnicities is by losing weight through dietary changes and increased physical activity. Metformin was also found to prevent the disease, though to a lesser degree.

"Both weight loss through lifestyle changes and metformin are effective strategies at treating diabetes," says Dr. Sadhu. "Of course, we would love to prevent diabetes with just weight loss, but we all know how difficult that can be, so often when a patient is diagnosed with prediabetes, their physician or provider will want to start metformin or other medications as an added therapy along with lifestyle changes."

However, the challenge, according to Dr. Sadhu, is that lifestyle changes — as many of us know — are easier said than done.

"I think everybody wants to be healthy," she says. "Who doesn't? It's very easy for physicians in a busy practice to say, 'You need to lose weight,' but it's really a partnership that takes time, and opening up the discussion is where we start. Let's figure out what will work for you, what motivates you and how you can make sustainable changes in your life."

The key, she says, is to find a motivating factor in your life that will inspire you to make the lifestyle changes necessary to prevent diabetes.

"You've got to put it in the long-term perspective," she says. "One of the most frequent responses to lifestyle changes is the lack of time in people's busy schedules. But the extra time needed now to exercise daily, and make healthy meals rather than eat processed, convenience foods is a small investment into the future. If you develop diabetes, think of the time it will take to manage your blood glucose daily with monitoring and medications, like insulin injection therapy. Not to mention the time to manage complications of diabetes such as heart attacks, strokes, blindness, kidney failure and more."

"No one wants to use our time to deal with a major health issues, but by prioritizing your health now, you can hopefully prevent prediabetes from advancing, avoid so many complications in the future and preserve your quality of life and have the time to do the things you enjoy in life," she adds.

Opt for a 'balanced diet' and avoid fad 'extremes'

"For a person with prediabetes specifically, I recommend a balanced diet lower in carbohydrates that you can actually keep up long-term and make the carbohydrates you do eat come from natural foods rather than processed foods," says Dr. Sadhu. "No extremes, no keto, no carnivore diets. Any of those fashionable diets tend not to work especially in the long term because they're not sustainable."

(Related: Is the Keto Diet Healthy? Weighing the Risks)

So, what does eating a balanced diet really mean? The five principles to creating a balanced plate include:

• Filling half your place with mostly non-starchy vegetables and fruits
• Adding a quarter-plate of whole grains
• Adding a quarter-plate of lean protein
• Keeping saturated fats, cholesterol and added sugars to a minimum
• Being mindful of portion sizes

"You also want to minimize ultra-processed foods and prioritize whole foods," she adds.

People tend to associate "whole foods" with the grocery store chain, but it actually refers to foods that are minimally processed that are found in their natural state or with minimal modifications. A strawberry is just that — a strawberry. The same goes for beans, grains, fish, nuts, seeds and vegetables: They're just one ingredient!

If you're prediabetic, diabetes is not inevitable

"Unfortunately, the development of type 2 diabetes is strongly genetic," says Dr. Sadhu. "However, it doesn't have to be the case where you're just inevitably waiting for a diagnosis."

"Do some patients have to work harder than the person who doesn't have a genetic history of the disease? Yes, because you have to fight that genetic tendency, but it's not the case that it has to be your fate," she says. "The power to change the trajectory of this disease is in our hands, so we should do it."

Are you eligible to join the CDC's National Diabetes Prevention Program?

Congress authorized the creation of the National Diabetes Prevention Program in 2010 based on the previous research concluded in previous trials like the one Dr. Sadhu mentioned.

Led by the CDC, the program offers evidence-based and cost-effective ways to help prevent type 2 diabetes. Visit the CDC website to learn more about the National DPP and to see if you qualify for eligibility.