What is prediabetes? Understanding the symptoms, risks, and treatment

A staggering 98 million American adults in the US (1 out of 3) have prediabetes¹ and more than 760 million adults worldwide are estimated to have either impaired glucose tolerance or impaired fasting glucose—conditions often used to define prediabetes.² While there can be signs and symptoms, more than 80% of US adults with prediabetes do not know they have it.¹ 

Prediabetes tends to be a precursor to type 2 diabetes and puts you at a higher risk of developing type 2 diabetes.³ However, while it’s an early warning sign, having prediabetes doesn’t mean you're guaranteed to develop type 2 diabetes.  

Research suggests that 30% of people with prediabetes progress to type 2 diabetes within an average of about 7 years,⁴ and early lifestyle changes can prevent or delay this progression.⁵ Using nutrition and exercise to lose weight helps. Every 2.2 pounds of weight lost reduces risk by 16%.⁶ 

With the right lifestyle and/or pharmacological interventions, many people are able to return blood glucose levels to a healthy range or delay progression. 

What is prediabetes?  

Prediabetes is a metabolic condition marked by elevated glucose levels that's linked to a higher risk of developing type 2 diabetes.⁷ 

Blood sugar exists on a spectrum, from healthy to prediabetes to type 2 diabetes. Prediabetes is considered the middle stage, where fasting blood glucose or A1C levels are higher than normal, but not yet high enough to qualify as type 2 diabetes.⁸  

In this stage, the body is already showing signs of insulin resistance—a condition that often begins years before blood sugar levels start to rise. Over time, it becomes harder to keep blood sugar in a healthy range, so blood sugar levels begin to rise. This can happen long before type 2 diabetes develops.   

What is insulin resistance? 

Insulin resistance occurs when the body’s cells don't respond effectively to insulin, forcing the pancreas to produce more insulin to maintain glucose levels in a normal range.  

Insulin resistance can be present for up to 10-15 years before blood sugar reaches levels high enough to be diagnosed as type 2 diabetes.⁹ At first, the body compensates. The extra insulin manages to keep glucose levels normal.   

As insulin resistance progresses, the pancreas can no longer keep up, leading to beta-cell dysfunction and rising glucose levels that are seen in prediabetes. Metabolic complications such as inflammation and fat build up in the liver (nonalcoholic fatty liver disease) can also occur.^10,11 If unaddressed, this can progress to type 2 diabetes.^8,12 

What's the difference between diabetes and prediabetes?  

Prediabetes and type 2 diabetes exist on the same “metabolic pathway,” just at different stages of dysfunction. The difference is in how high glucose levels are. Once glucose levels have risen to the level of type 2 diabetes, insulin resistance tends to be greater. 
 
Prediabetes is widely recognized as a high-risk state that can progress to type 2 diabetes.⁷ However, progression isn’t one-size-fits-all. Research suggests that the risk of progression depends on where you start. People with a higher A1c in the prediabetes range (6.0-6.4%) tend to develop diabetes faster than those with lower levels (5.7-6.0%).^4,13,14 The good news is that early lifestyle changes can prevent or delay this progression.⁵ 

Prediabetes glucose ranges 

A formal diagnosis of prediabetes is made when any of the following are present:  

• Fasting glucose is between 100-125 mg/dL (milligrams per deciliter). 

• HbA1c is 5.7-6.4% (this is a measure of average blood glucose level over the past ~3 months).  

• Glucose is between 140-199 mg/dL following an oral glucose tolerance test. 

These changes in your metabolism develop gradually, and metabolic dysfunction often begins years before glucose is high enough to be detected on a lab test.¹² 

Is prediabetes serious?  

Yes. Prediabetes should be taken seriously because it signals early metabolic dysfunction. If left unaddressed, it significantly increases the risk of progressing to type 2 diabetes, as well as major health conditions such as heart and kidney disease.¹⁵ 

Importantly, even individuals with prediabetes who never develop diabetes still face elevated long-term health risks compared with those who maintain normal glucose levels.⁴ In other words, prediabetes is not a benign condition—it deserves early attention and action.  

What increases your risk of developing prediabetes?  

Several factors, including overweight or obesity, a family history of diabetes, physical inactivity, hypertension, abnormal cholesterol or triglycerides, gestational diabetes, and polycystic ovary syndrome (PCOS) can increase the risk of developing prediabetes.^8,15 

Certain populations, including African American, Hispanic/Latino, Native American, and Asian/Pacific Islander communities, have higher risk.⁸ 

Diet also plays a role. Eating a diet high in refined or rapidly digested carbohydrates can trigger repeated glucose spikes and increased insulin demand. Over time, this can contribute to insulin resistance and a higher risk of prediabetes.¹⁶ 

As discussed earlier, insulin resistance—and the metabolic complications that often accompany it—is one of the strongest predictors of progressing to prediabetes and type 2 diabetes.¹⁷ 

What are the signs and symptoms of prediabetes?  

Most people with prediabetes don’t notice any symptoms. In many cases, the condition is only discovered through routine blood work, which is why screening is so important.³ 

However, some individuals may experience fatigue, increased hunger/appetite, blurry vision, slower wound healing, or frequent skin infections.³ 

Because insulin resistance often develops years before glucose rises, some signs are related to metabolic dysfunction, such as:⁹ 

• High blood pressure 

• Elevated triglycerides 

• Difficulty losing weight 

• Skin tags or patches of darkened skin (acanthosis nigricans) 

Who does prediabetes affect? 

Prediabetes affects roughly 1 in 3 adults in the United States, and most don’t know they have it.¹ Globally, more than 760 million adults are estimated to have early signs of abnormal blood sugar (often called prediabetes). This number is expected to rise to over 1 billion by 2045.² 

While excess body weight increases risk, prediabetes can also develop in people with a “normal” BMI, influenced by genetics, diet quality, sleep, and physical activity levels.^18,19  

What happens now that I’ve had a prediabetes diagnosis? 

A prediabetes diagnosis can feel alarming, but it’s also a powerful opportunity to take action.  

Prediabetes does not always progress to type 2 diabetes, and with the right steps, blood sugar can return to a healthier range.⁵ 

Treatment typically begins with lifestyle changes, such as improving diet quality, increasing physical activity, and aiming for modest weight loss. In some cases, prescription medication like metformin may be recommended to support these efforts.²⁰ 

The goal is to bring your glucose levels back into a healthy range and reduce insulin resistance. Tools like continuous glucose monitors (CGMs) can help you understand how your body responds to food and physical activity, giving you real-time feedback and making it easier to build habits that support your metabolic health.  

Because glucose rises and falls every day—and in between routine lab tests—a CGM is the only practical way to see how often your levels rise above a healthy range (>140 mg/dl) throughout the entire day.  

And this matters: recent research using CGMs shows that people who spend less time above the healthy glucose range (70-140mg/dL) have a lower risk of developing type 2 diabetes over the next 5 years.²¹ 

How do you treat or reverse prediabetes?  

The most effective approach is lifestyle intervention, which has been shown to prevent or delay type 2 diabetes^5,20. Metformin, a common diabetes drug, is also effective, though it reduces risk by about half as much (31% vs 58% with lifestyle).⁵ Effective treatment focuses on: 

• Diet: Lower intake of refined carbohydrates and added sugars. Build meals rich in protein, fiber, and healthy fats to improve glucose stability and reduce insulin spikes. 

• Exercise: Regular physical activity, especially strength training, can improve insulin sensitivity and help your body use glucose more effectively.²⁰ 

• Weight management: Even modest weight loss (around 5–7% of body weight) can significantly improve glucose levels and long-term outcomes.⁵ 

• Medication: The prescription medication metformin may be used in certain cases, especially for individuals at higher risk of progressing to type 2 diabetes.²⁰ 

Everyone’s path to managing prediabetes looks different, so it’s important to work with your healthcare provider and find an approach that works for you.  

Check your prediabetes risk 

If you haven’t been tested for prediabetes yet, the CDC offers a simple 1-minute online screening test to help estimate your risk.  This online screening tool isn’t a diagnosis, but it can help you understand your risk level and decide if you should talk to your healthcare provider about getting more formal blood work done. Because most people with prediabetes have no symptoms, screening can be an important first step. CDC Prediabetes Risk Test 

A final note from Lingo 

A prediabetes diagnosis doesn’t mean you’re destined to develop type 2 diabetes. With the right interventions, such as adjusting your diet, staying active, and using tools like a CGM, you can take meaningful steps to improve your metabolic health and potentially reverse some of the changes that have started. 

Using real-time glucose insights from Lingo can help you personalize your approach, showing how your body responds to different foods, activities, sleep, stress, and more. By minimizing glucose spikes and spending more time in the healthy range, you can support better metabolic health and work toward long-term glucose stability.