Type 1 Diabetes vs. Type 2 Diabetes: What’s the Difference?

It all comes down to insulin production.

Loading the player...

Type 1 and type 2 diabetes can certainly have similar symptoms and complications, but it’s a mistake to conflate them. Yet, conversations about diabetes on your Twitter feed or the evening news often fail to specify, referring simply to “diabetes” and ignoring the uniqueness of the two types.

“In type 1 diabetes, your body cannot produce any insulin,” says Sonal Chaudhry, MD, an endocrinologist at NYU Langone Health in New York City. “In type 2 diabetes, your body produces insulin, but may not be enough to produce enough to overcome the peripheral insulin resistance.”

Insulin is a hormone secreted by the pancreas that helps move blood glucose from the bloodstream to cells for energy, according to Dr. Chaudhry. When the body does not have enough insulin, excess glucose remains in the bloodstream, leading to high blood sugar, known as hyperglycemia. (Learn more about how insulin works here.) Over time, this can damage critical organs like your heart, kidneys, and brain.

In type 1 diabetes, previously known as “juvenile diabetes,” the immune system attacks the pancreas and prevents it from making insulin. “There’s usually a genetic predisposition,” says Minisha Sood, MD, an endocrinologist in New York City, “and then some inciting event—some precipitating factor—that set off the immune system.” As a result, the immune system attacks the pancreas.

Patients with type 2 diabetes, on the other hand, do make insulin, but their livers and muscles do not respond to the insulin as they should, which is known as insulin resistance.

After eating a meal, they may see a blood sugar spike because the insulin is not moving glucose out of the bloodstream. “Their body will produce insulin, and produce a lot of it,” says Dr. Chaudhry, “but they may not be able to overcome that insulin resistance.”

Over time, the pancreas may lose its ability to produce insulin with type 2 diabetes, and patients may need to take insulin injections to manage blood sugar, according to Dr. Sood. On the other hand, patients with type 1 diabetes need insulin immediately.

Previously, experts often distinguished between type 1 and type 2 diabetes based on the age of diagnosis, which is why type 1 diabetes used to be called “juvenile diabetes.” That’s changed: Adult-onset type 1 diabetes has become more common than it used to be, just as young children are now being diagnosed with type 2 diabetes due to an increase in childhood obesity and sedentary lifestyles.

Regardless of the type of diabetes, patients with either type 1 diabetes or type 2 diabetes need to manage their blood sugar levels. Here are the worst foods for diabetes and lifestyle habits for better blood sugar management.