What’s the Difference Between Type 1 and Type 2 Diabetes?

Type 1 and type 2 diabetes are both defined by high blood sugar levels. Consistently high blood sugar can lead to similar symptoms and complications in either case. But type 1 diabetes and type 2 diabetes are different diseases in many other ways.

Here’s what you need to know to be health-savvy in the era of a diabetes epidemic.

Diabetes is related to high blood sugar, but the type of diabetes determines why your blood sugar level is high.

What Type 1 Diabetes Does to the Body

People with type 1 diabetes self-administer insulin every day for the rest of their lives. Using too much or too little insulin leads to both short- and long-term health issues. If type 1 diabetes is not managed carefully, it can lead to devastating consequences, such as a diabetic coma, advanced kidney disease, blindness, or amputation.

What Type 2 Diabetes Does to the Body

This blood sugar rise can result in the same damaging consequences as in type 1 diabetes, including cardiovascular disease, kidney failure, neuropathy, and early death.

Type 2 diabetes treatments — both medication and lifestyle changes — are mostly designed to correct the root cause of insulin resistance, so that the insulin your body does make works more effectively, bringing blood sugar levels down. If those treatments are ineffective, some patients will eventually need to self-administer insulin as a medicine.

What Causes Type 1 Diabetes?

“Type 1 diabetes is an autoimmune disease. The body’s immune system attacks the cells in the pancreas that make insulin,” says Andjela Drincic, MD, a professor in the division of diabetes, endocrinology, and metabolism at the University of Nebraska Medical Center in Omaha.

What Causes Type 2 Diabetes?

“The cause of type 2 diabetes is multifactorial,” says Dr. Drincic. “People inherit genes that make them susceptible to type 2, but lifestyle factors, like obesity and inactivity, are also important. In type 2 diabetes, at least in the early stages, there is enough insulin, but the body becomes resistant to it.”

The onset of type 1 diabetes may be more gradual in adults than in children. Some adults have a subtype of type 1 diabetes called latent autoimmune diabetes in adults (LADA), which progresses especially slowly. This means that type 2 medications may seem effective for several years before insulin therapy is necessary.

Because of its slower onset, type 1 diabetes is often misdiagnosed as type 2 diabetes in adults.

The Symptoms of Type 1 Diabetes

These symptoms include increased thirst, frequent urination, unexplained weight loss, and blurred vision. People may also experience rapid breathing, dry skin, fruity breath, and nausea.

In severe cases, undiagnosed type 1 diabetes can lead to a condition called diabetic ketoacidosis (DKA). DKA is life-threatening and should be treated in an emergency room with intravenous fluids and insulin. Many people with type 1 diabetes are diagnosed only after developing DKA. If you suspect you have DKA, get immediate treatment.

The Symptoms of Type 2 Diabetes

An A1C test measures your average blood sugar level over the past few months. A glucose tolerance test measures blood sugar after a sugary drink is given.

• Testing for Autoantibodies Autoantibodies develop when the immune system attacks the cells in the pancreas that produce insulin. The presence of autoantibodies indicates type 1 diabetes.
• C-Peptide Levels C-peptides indicate how much insulin your pancreas is producing. People with type 1 diabetes have very low C-peptide levels, while people with type 2 tend to have very high C-peptide levels.

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Your doctor may suspect type 2 diabetes based on risk factors such as obesity and family history, or symptoms such as dark, velvety skin (acanthosis nigricans). Considering the rate of misdiagnosis, it may be prudent to rule out type 1 diabetes, regardless of your weight or age, by testing your C-peptide levels or checking for autoantibodies.

Treating and managing type 1 or type 2 diabetes can involve multiple lifestyle habit changes, medications, and types of technology, and there is a great deal of overlap between the two conditions.

Diet, Exercise, and Lifestyle Changes for Type 1 and Type 2 Diabetes

Diabetes doesn’t mean that you need to eat perfectly, but making healthy choices may be the single most important thing you can do to keep your blood sugar in a healthy range.

• Eat more whole foods and vegetables.
• Eat fewer highly processed foods.
• Watch your carbohydrate intake.
• Look for lean proteins or plant-based proteins.
• Get regular exercise.
• Limit alcohol consumption.
• Quit smoking.
• Prioritize quality sleep.

Insulin for Type 1 Diabetes

The treatment of both type 1 and type 2 diabetes relies on the use of drugs, which help lower blood glucose levels.

Insulin is often the most important drug in the treatment of diabetes. “The big difference is that everybody with type 1 diabetes needs to take insulin,” says Shannon Knapp, RN, CDCES, manager of diabetes care and education at Cleveland Clinic in Ohio.

Today’s insulin options are vast, and so are the technologies you can use to dose and administer insulin. Insulin comes in multiple forms. It can be administered by injection or infused continuously with an insulin pump. Inhaled insulin is also available. Some newer insulin pumps offer a hybrid closed-loop system that communicates directly with a continuous glucose monitor, making automatic adjustments to insulin doses.

Drugs for Type 2 Diabetes

Other options include:

• Glucagon-like peptide 1 (GLP-1) and dual GLP-1/gastric inhibitory peptide receptor agonists, which have become famous for their ability to induce weight loss as well as control blood sugar
• Dipeptidyl peptidase 4 inhibitors
• Sodium-glucose cotransporter 2 inhibitors (SGLT2s)
• Sulfonylureas
• Thiazolidinediones
• Alpha-glucosidase inhibitors

These medications work in different ways to improve blood sugar levels or insulin resistance. The newest drug classes, GLP-1 receptor agonists and SGLT2 inhibitors, also offer long-term protection to kidney and heart health.

Everyone reacts differently to these medications, which means you should tell your doctor right away if you’re experiencing severe side effects or if you aren’t seeing improvements in your blood sugar levels.

Finally, insulin is an option for people with type 2 diabetes who have been unable to keep their blood sugar at a safe level with the other drugs and lifestyle changes. “Over time, if the pancreas stops making insulin, some people with type 2 will also need insulin,” says Knapp.

Blood Sugar Monitoring

When they are first diagnosed, most people with diabetes are given a prescription for a blood glucose meter. These devices measure blood sugar levels from a drop of blood; the measurements are sometimes called finger sticks because the devices use a sharp lancet to draw blood from the fingertips.

A newer piece of technology, a continuous glucose monitor (CGM) can measure blood sugar levels around the clock. This device adheres to the upper arm, torso, or elsewhere on the body. A small hairlike cannula penetrates below the skin. The CGM automatically updates a smartphone app or a dedicated CGM transmitter with new measurements. It can also raise an alarm if blood sugar levels are trending dangerously high or low.

A partial list of complications includes:

• Retinopathy (eye disease, which can lead to vision loss)
• Nephropathy (kidney disease)
• Neuropathy (numbness, tingling, or pain in the hands, feet, and legs)
• Heart disease (including stroke and heart attack)

These conditions can become severe, especially if diabetes is left unmanaged for a long time. Some of the worst outcomes of diabetes include amputation, blindness, and early death. People with type 1 or type 2 diabetes are both at risk.

Can Type 1 Diabetes Be Prevented?

Can Type 2 Diabetes Be Prevented?

It takes effort, but type 2 diabetes can be prevented before it develops.

“The best cure for type 2 diabetes is prevention, and research on that is very exciting,” Drincic says. “Losing a moderate amount of weight and exercising regularly can reduce or delay type 2 diabetes significantly.”

Some people — especially those who have been recently diagnosed with type 2 diabetes — can achieve normal blood sugar levels exclusively through changes in diet, exercise, and weight loss. Others will always need medicine to help keep their blood sugar levels under control, no matter how carefully they follow diet and exercise recommendations.

Additional reporting by Chris Iliades, MD.