Could You Have Diabetes and Not Know It?

June 16th, 2026

man kayaking in pond — Diabetes is a chronic condition where your body can’t properly use or make insulin, the hormone that helps turn food into energy.

Diabetes is becoming more personalized, more technology-driven, and more preventative than before.

Jared M. Darlian, DO, Dartmouth Hitchcock Clinics Nashua

Stephen Richert, RN, was a teenager when he was diagnosed with Type 1 diabetes.

“At the time, I had no idea someone at my age could get diabetes, because I only knew about Type 2 diabetes, which normally would happen to your grandparents,” says Richert, now 43, a diabetes care and education specialist at Alice Peck Day Memorial Hospital, a member of Dartmouth Health.

According to the Centers for Disease Control and Prevention (CDC), about 40 million people in the U.S. have diabetes, and millions are living with diabetes and don’t know it.

If you notice any warning signs or symptoms, getting evaluated early can help you avoid serious problems and start treatment sooner. Here’s what to watch for.

What is diabetes?

“A lot of people think that because diabetes is so common, it’s not that serious,” explains Jared M. Darlian, DO, a family medicine physician at Dartmouth Hitchcock Clinics Nashua. “Diabetes is something that can affect every part of your health.”

Diabetes is a chronic condition where your body can’t properly use or make insulin, the hormone that helps turn food into energy. Without enough insulin, sugar builds up in your blood, which over time can cause serious health problems.

“The good news is that people who manage diabetes well can live long lives and have very few, if any, complications,” Darlian explains.

What’s the difference between Types 1 and 2 diabetes?

Type 1 diabetes is when no insulin is produced. It’s an autoimmune disease, causing your immune system to attack insulin-producing cells in your pancreas.

For Type 2 diabetes, too much insulin is produced because your body can’t use insulin as well as it should and tries to keep up with the demand. About 95% of people with diabetes in the U.S. have Type 2. Cases are increasing, especially among young people.

“For younger people, it’s a perfect storm with easier access to calorie-dense, low-nutrient processed foods, and more time spent online instead of being active. That’s driving the rise in diabetes,” Darlian says.

What about prediabetes?

Prediabetes is when your blood sugar is higher than normal, but not high enough to be diabetes.

Most people don’t know they have prediabetes, since it often has no symptoms. But it doesn’t necessarily lead to diabetes.

“It means you’re not diabetic yet, but your body’s showing some signs it’s having a hard time keeping up,” Darlian says. “But you can reverse it.”

The best way to find out if you are prediabetic is to ask your doctor for a routine blood test.

What are diabetes symptoms?

Type 1 diabetes symptoms often appear suddenly, over days or weeks. Type 2 symptoms develop more gradually and can go unnoticed for months or years.

Type 1 diabetes symptoms:

Increased thirst and urination
Extreme hunger
Unexplained weight loss
Fatigue
Blurred vision
Irritability
Fruity breath, nausea, or vomiting (in severe cases)

Type 2 diabetes symptoms:

Increased thirst and urination
Increased hunger
Fatigue
Blurred vision
Slow-healing wounds
Frequent infections
Numbness or tingling in hands or feet
Darkened skin (neck or armpits)
Unexplained weight loss

Can early detection make a difference?

If diabetes goes undiagnosed or untreated for a long time, high blood sugar can gradually damage blood vessels and nerves throughout the body. The damage often happens slowly, and you might not realize there’s a problem until complications develop.

Early detection can help you make lifestyle changes or start treatment to prevent the progression to Type 2 diabetes and avoid complications.

“We can do something about diabetes if we catch it earlier,” Darlian says.

With early detection, lifestyle changes, and treatment, blood sugar control can be improved and, in some cases, the progression of the disease can be prevented or delayed.

Common screening tests include:

An A1C test that shows your average blood sugar over the past two to three months. An A1C between 5.7% and 6.4% means you may have prediabetes; 6.5% or higher could mean diabetes.
Fasting blood sugar, which checks your blood sugar after eight hours without eating.
An oral glucose tolerance test that measures how your body handles sugar before and after a sweet drink.

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How is diabetes managed?

“Diabetes is a self-managed condition, so you are required to be the expert about how your body is working,” Richert says.

Type 1 diabetes requires insulin because the body cannot make it. Type 2 diabetes is often managed with healthy lifestyle changes, medication, and sometimes insulin to help control blood sugar levels.

The main goal is to keep blood sugar in a healthy range and lower your risk for complications. That means checking your blood sugar, eating well, staying active, taking medication as needed, managing stress, and seeing your doctor regularly.

Advances in medicine

Research shows promising advances in diabetes care, including smarter, smaller insulin pumps and wearable devices that can check blood sugar without finger pricks.

Darlian also notes that genetic technologies are being developed to identify individuals at risk for Type 1 diabetes earlier, enabling preventive interventions.

“Diabetes is becoming more personalized, more technology-driven, and more preventative than before,” Darlian says.

Studies show that some people with Type 2 diabetes can achieve normal blood sugar levels without diabetes medications through significant weight loss, intensive lifestyle changes, or certain medical treatments. While remission isn't possible for everyone, it's changing how experts think about Type 2 diabetes.

Researchers are also working on helping patients with Type 1 diabetes stop taking insulin by using stem-cell therapy.

Above all, Richert says managing diabetes requires close attention to many different aspects of your daily life.

“Diabetes is a dynamic dance between food, medication, sleep, stress, and exercise,” he says. “What you put into managing your diabetes is what you’ll get out of it.”