Understanding the main types of diabetes

Hearing that someone has diabetes means that there is an issue with how their body regulates glucose, or blood sugar. But that doesn’t tell the whole story. Diabetes can have different causes — sometimes their body doesn’t produce any insulin (a hormone that transports glucose from the blood to cells), sometimes their body can’t use insulin effectively. And each cause has its own treatment plan. That’s why, under the umbrella of diabetes, there are distinct types: type 1 diabetes, type 2 diabetes, and gestational diabetes. Here’s what to know about each type.

Type 1 diabetes

Accounting for about 5% to 10% of diabetes cases, type 1 diabetes (T1D) is an autoimmune disorder. It’s sometimes referred to as juvenile diabetes, since many people with the condition get diagnosed in their youth, but adults at any age can develop T1D too. It happens when the immune system mistakenly attacks cells in the pancreas that produce insulin, damaging them enough that the pancreas can only make a little bit of insulin (or, in some cases, none at all).

“We need insulin in our body to control blood sugars,” says Dr. Amy Warriner, M.D., a professor in the division of endocrinology, diabetes and metabolism at the University of Alabama at Birmingham and director of the UAB Weight Loss Medicine program. Without enough of it, glucose stays in the blood and blood sugar levels rise. Once your A1C (a measure of blood sugar over time) hits 6.5%, you can be diagnosed with T1D.

Type 1 diabetes risk factors

Anyone can develop T1D, and researchers still aren’t sure exactly why it happens in some people and not others. What they do know is that genetics play a big role, and having a parent with the disease raises your risk. Interestingly, says Warriner, your father’s history may matter more here. “What we’ve found with the research is that it’s more likely to be genetically inherited from paternal lines than maternal lines.” The American Diabetes Association puts it at a 1 in 17 chance of winding up with T1D if your dad has the condition, versus 1 in 25 or 1 in 100 if your mother does, depending on her age at your birth. Other potential factors include exposure to certain viruses, environment, and race.

Type 1 diabetes symptoms

T1D often develops relatively quickly, but symptoms may not show up early on. If they do, they can include things like frequent bathroom trips, feeling extremely thirsty, fatigue, and weight loss. Since the condition often impacts children, parents and caregivers may be the ones who notice the signs, such as an uptick in accidents in kids who are potty-trained or an insatiable thirst.

Type 1 diabetes treatments

“As soon as someone is diagnosed with T1D, they get started on insulin,” says Warriner. “No ifs, ands, or buts.” This is the case even when insulin production hasn’t stopped completely — a period known as the honeymoon phase. The insulin can be administered through daily injections or an insulin pump.

Glucose monitoring is also needed to check blood sugar levels throughout the day. You could do this by poking your finger and putting a drop of blood on a test drip, but monitoring is typically done through a wearable device called a continuous glucose monitor (CGM). This device provides the patient and their clinician with more information, in addition to alerting patients to high or low blood sugar episodes.

While type 1 diabetes can be managed, it’s a lifelong condition that can never be cured or go into remission.

Type 2 diabetes

If you have type 2 diabetes (T2D), your pancreas still releases insulin, but your body just doesn’t respond to it the way it should — something called insulin resistance. Over time, this causes blood sugar levels to rise. Like T1D, an A1C level of 6.5% means you have T2D.

Type 2 diabetes tends to develop gradually, with the pancreas not able to produce enough insulin to overcome the insulin resistance. This leads to gradual increase in blood sugar after meals and while fasting. Gradual is an important keyword here because people with T2D often don’t notice symptoms of the condition.

Type 2 diabetes risk factors

One of the main risk factors for T2D is having overweight or obesity. The excess fat — especially when it’s visceral fat located in your midsection and muscles — is frequently associated with insulin resistance. Inactivity also raises your risk, since physical activity improves insulin sensitivity.

Like with type 1 diabetes, genetics are also a player. Research reveals that if both of your parents had or have T2D, you have a 70% chance of developing it yourself — and even just one parent with the condition puts you at a 40% higher risk. Other factors that increase your risk: a history of gestational diabetes or prediabetes, polycystic ovary syndrome (PCOS), long-term use of steroid medications, and coming from marginalized racial and ethnic communities. (The latter is largely due to complex disparities in social determinants of health, such as decreased access to medical care.)

Type 2 diabetes symptoms

Since T2D can slowly develop, you will likely not notice any symptoms, says Dr. Disha Narang, M.D., an endocrinologist and the director of obesity medicine at Endeavor Health in Skokie, Illinois.

Over time, however, you may experience some classic symptoms, like having to pee more often, being super thirsty, or feeling very tired. You may also experience some unusual signs that you might not immediately connect to diabetes like acanthosis nigricans, a darkening of the skin (commonly on the back of the neck), recurrent yeast infections, or urinary tract infections.

Type 2 diabetes treatments

Unlike with T1D, people with T2D have a variety of treatment options to choose from. Alongside standard glucose monitoring, the most commonly prescribed treatments are oral medication, injectable medication, insulin therapy, and lifestyle changes.

Oral medications, like metformin, are often prescribed to help the body use insulin, ramp up insulin production, or decrease insulin resistance. There are also newer injectable GLP-1 medications that reduce blood sugar and help reduce body fat, like Ozempic (semaglutide) and Mounjaro (tirzepatide). If blood sugar is still above where it should be, then insulin is sometimes prescribed, says Narang.

A critical piece of any T2D treatment plan, however, is lifestyle — including more physical activity, a healthier diet, and, in many cases, weight loss. Experts say that losing even 5% to 7% of your weight can help improve blood sugar levels in people who have overweight or obesity with T2D. Higher weight loss can even help your blood sugar move out of the type 2 diabetes range.

That’s where a lifestyle program like WeightWatchers for Diabetes can help. The plan guides you toward foods that are less likely to raise your blood sugar, gives you access to one-on-one visits with a registered dietitian, and connects you with a motivating community to keep you going. In six months, members lost an average of 5.7% of their weight, and reduced A1C levels by .76%.*

What's the difference between type 1 and type 2 diabetes?

It’s all about the insulin. As we mentioned earlier, your pancreas releases insulin, which brings glucose (blood sugar) to your cells for energy. In T1D, the pancreas no longer provides adequate amounts of insulin to keep blood sugar levels in check. In T2D your pancreas still produces insulin (and lots of it), but it isn’t sufficient for helping to get the glucose into cells.

Prediabetes

Prediabetes is when your blood sugar levels are elevated, but they haven’t passed the threshold for type 2 diabetes. It can be diagnosed in one or more of the following ways:

• A1C level between 5.7% and 6.4%.
• Fasting plasma glucose between 100 and 125 mg/dl
• Oral glucose tolerance test (OGTT) between 140 and 199 mg/dl.

Prediabetes is incredibly widespread: The CDC estimates that more than 1 in 3 adults in the U.S. have prediabetes, with the vast majority completely unaware that they do. Prediabetes isn’t limited to adults: Nearly 1 in 5 teens between 12 and 18 years old also have the condition.

Prediabetes risk factors

Since type 2 diabetes is, in many ways, a progression of prediabetes, many of the risk factors are the same, including: family history, elevated BMI, inactivity, and conditions such as Polycystic Ovary Syndrome (PCOS).

Prediabetes symptoms

Since prediabetes is the earliest stage of high glucose, you will likely not even notice anything going on. “Symptoms like frequent urination and increased thirst typically present in much more severe cases of diabetes,” says Narang.

So then how are you supposed to catch it early? Stick with your annual physical. Once you hit 35, your doctor should start screening you for prediabetes every three years.

Prediabetes treatments

Prediabetes isn’t a set-in-stone path toward T2D. Frame your diagnosis as a nudge, says Barbara Sassower, a registered dietitian nutritionist and certified diabetes care and education specialist. “I often explain it to clients like this: Would you wait around to see flames before calling the fire department, or would you get help when you see the smoke?”

Early action can make a major difference. “You have a better chance of putting prediabetes into remission than putting type 2 diabetes into remission,” says Warriner. “So if you’re able to make lifestyle changes before you’re diagnosed with diabetes, that’s optimal.” These changes echo those for T2D and include getting more exercise, a nutrient-rich diet, and reducing processed foods and portion sizes as a way to lose weight if needed. The WeightWatchers Points Program is built around helping you make these kinds of lifestyle changes (and is proven to help with weight loss and lowering your glucose levels if you have prediabetes).

Gestational diabetes

Gestational diabetes occurs exclusively during pregnancy. The uptick in hormones can create insulin resistance and lead to a rise in blood sugar levels.

While gestational diabetes occurs in just 5% to 9% of pregnancies nationwide, recent research suggests that number is going up. A 2021 study found that the rate of gestational diabetes rose around 30% between 2011 and 2019. Researchers pointed to factors like obesity and low exercise rates to help to explain the increase, though they’re studying this further to learn more.

Gestational diabetes risk factors

Obviously, the biggest risk factor here is pregnancy. But your risk increases if you've had gestational diabetes in the past, have a family history of T2D, have a BMI over 30, previously gave birth to a baby over nine pounds, and have other related conditions, such as high blood pressure, PCOS, or prediabetes. It’s also more pronounced in certain racial or ethnic groups. The same communities at higher risk for T2D — including African Americans, Hispanic or Latino, American Indians, and Alaska Natives — are also at higher risk for gestational diabetes.

Gestational diabetes symptoms

Gestational diabetes usually occurs without symptoms, but it’s standard practice to test for it in the second trimester or early in the third trimester, usually between 24 and 28 weeks.

Gestational diabetes treatments

Healthcare providers take gestational diabetes very seriously because of its potential impact on both baby and the person who is pregnant. For the baby, risks include premature birth or low blood sugar levels, both of which may require time in the Neonatal Intensive Care Unit (NICU). For the one who is pregnant, gestational diabetes can increase your chance of developing preeclampsia, a dangerous condition marked by high blood pressure.

For this reason, women with gestational diabetes are closely monitored to make sure blood sugar levels are under control. Lifestyle changes like diet modifications (through medical nutrition therapy) are key, and your OB or midwife may recommend a dietitian or nutritionist to help you implement these.

If high blood sugar levels persist, Narang says providers are quick to turn to other therapies — most commonly insulin, since it won’t impact the baby. “It’s imperative to make sure that we are maintaining tight blood sugar control in our pregnant population,” she says.

Once the baby is born, gestational diabetes goes away on its own. To make sure everything looks good, you’ll likely have your blood sugar levels tested between one and three months postpartum.

Can you have more than one type of diabetes?

There can be an overlap in characteristics between type 1 and type 2 diabetes. Someone with type 1 diabetes may develop insulin resistance due to weight gain and other factors, which necessitates increasing insulin doses or adding medications that are commonly used for the management of type 2 diabetes.

On the other hand, a patient with type 2 diabetes may see a decline in insulin production over time, leading to the initiation of insulin to manage their diabetes.