What Is Type 2 Diabetes?
Type 2 diabetes is a lifelong disease that keeps your body from using insulin the way it should. People with type 2 diabetes are said to have insulin resistance.
People who are middle-aged or older are most likely to get this kind of diabetes. It used to be called adult-onset diabetes. But type 2 diabetes also affects kids and teens, mainly because of childhood obesity.
Type 2 is the most common type of diabetes. There are about 29 million people in the U.S. with type 2. Another 84 million have prediabetes, meaning their blood sugar (or blood glucose) is high but not high enough to be diabetes yet.
Signs and Symptoms of Type 2 Diabetes
The symptoms of type 2 diabetes can be so mild that you don't notice them. About 8 million people who have it don't know it. Symptoms include:
- Being very thirsty
- Peeing a lot
- Blurry vision
- Being cranky
- Tingling or numbness in your hands or feet
- Fatigue/feeling worn out
- Wounds that don't heal
- Yeast infections that keep coming back
- Feeling hungry
- Weight loss without trying
- Getting more infections
If you have dark rashes around your neck or armpits, see your doctor. These are called acanthosis nigricans, and they can be signs that your body is becoming resistant to insulin.
Causes of Type 2 Diabetes
Your pancreas makes a hormone called insulin. It helps your cells turn glucose, a type of sugar, from the food you eat into energy. People with type 2 diabetes make insulin, but their cells don't use it as well as they should.
At first, your pancreas makes more insulin to try to get glucose into your cells. But eventually, it can't keep up, and the glucose builds up in your blood instead.
Usually, a combination of things causes type 2 diabetes. They might include:
- Genes. Scientists have found different bits of DNA that affect how your body makes insulin.
- Extra weight. Being overweight or obese can cause insulin resistance, especially if you carry your extra pounds around your middle.
- Metabolic syndrome. People with insulin resistance often have a group of conditions including high blood sugar, extra fat around the waist, high blood pressure, and high cholesterol and triglycerides.
- Too much glucose from your liver. When your blood sugar is low, your liver makes and sends out glucose. After you eat, your blood sugar goes up, and your liver will usually slow down and store its glucose for later. But some people's livers don't. They keep cranking out sugar.
- Bad communication between cells. Sometimes, cells send the wrong signals or don't pick up messages correctly. When these problems affect how your cells make and use insulin or glucose, a chain reaction can lead to diabetes.
- Broken beta cells. If the cells that make insulin send out the wrong amount of insulin at the wrong time, your blood sugar gets thrown off. High blood sugar can damage these cells, too.
Type 2 Diabetes Risk Factors
Certain things make it more likely that you’ll get type 2 diabetes. The more of these that apply to you, the higher your chances of getting it are. Some things are related to who you are:
- Age. 45 or older
- Family. A parent, sister, or brother with diabetes
- Ethnicity. African American, Alaska Native, Native American, Asian American, Hispanic or Latino, or Pacific Islander American
Risk factors related to your health and medical history include:
- Heart and blood vessel disease
- High blood pressure, even if it's treated and under control
- Low HDL ("good") cholesterol
- High triglycerides
- Being overweight or obese
- Having a baby who weighed more than 9 pounds
- Gestational diabetes while you were pregnant
- Polycystic ovary syndrome (PCOS)
Other things that raise your risk of diabetes have to do with your daily habits and lifestyle. These are the ones you can do something about:
Type 2 Diabetes Diagnosis and Tests
Your doctor can test your blood for signs of type 2 diabetes. Usually, they’ll test you on 2 days to confirm the diagnosis. But if your blood glucose is very high or you have many symptoms, one test may be all you need.
- A1c. It's like an average of your blood glucose over the past 2 or 3 months.
- Fasting plasma glucose. This is also known as a fasting blood sugar test. It measures your blood sugar on an empty stomach. You won't be able to eat or drink anything except water for 8 hours before the test.
- Oral glucose tolerance test (OGTT). This checks your blood glucose before and 2 hours after you drink something sweet to see how your body handles the sugar.
Type 2 Diabetes Treatment
Managing type 2 diabetes includes a mix of lifestyle changes and medication.
You may be able to reach your target blood sugar levels with diet and exercise alone.
- Weight loss. Dropping extra pounds can help. While losing 5% of your body weight is good, losing at least 7% and keeping it off seems to be ideal. That means someone who weighs 180 pounds can change their blood sugar levels by losing around 13 pounds. Weight loss can seem overwhelming, but portion control and eating healthy foods are a good place to start.
- Healthy eating. There’s no specific diet for type 2 diabetes. A registered dietitian can teach you about carbs and help you make a meal plan you can stick with. Focus on:
- Eating fewer calories
- Cutting back on refined carbs, especially sweets
- Adding veggies and fruits to your diet
- Getting more fiber
- Exercise. Try to get 30 to 60 minutes of physical activity every day. You can walk, bike, swim, or do anything else that gets your heart rate up. Pair that with strength training, like yoga or weightlifting. If you take a medication that lowers your blood sugar, you might need a snack before a workout.
- Watch your blood sugar levels. Depending on your treatment, especially if you’re on insulin, your doctor will tell you if you need to test your blood sugar levels and how often to do it.
If lifestyle changes don’t get you to your target blood sugar levels, you may need medication. Some of the most common for type 2 diabetes include:
- Metformin (Fortamet, Glucophage, Glumetza, Riomet). This is usually the first medication used to treat type 2 diabetes. It lowers the amount of glucose your liver makes and helps your body respond better to the insulin it does make.
- Sulfonylureas. This group of drugs helps your body make more insulin. They include glimepiride (Amaryl), glipizide (Glucotrol, Metaglip), and glyburide (DiaBeta, Micronase).
- Meglitinides. They help your body make more insulin, and they work faster than sulfonylureas. You might take nateglinide (Starlix) or repaglinide (Prandin).
- Thiazolidinediones. Like metformin, they make you more sensitive to insulin. You could get pioglitazone (Actos) or rosiglitazone (Avandia). But they also raise your risk of heart problems, so they aren’t usually a first choice for treatment.
- DPP-4 inhibitors. These medications -- linagliptin (Tradjenta), saxagliptin (Onglyza), and sitagliptin (Januvia) -- help lower your blood sugar levels, but they can also cause joint pain and could inflame your pancreas.
- GLP-1 receptor agonists. You take these medications with a needle to slow digestion and lower blood sugar levels. Some of the most common ones are exenatide (Byetta, Bydureon), liraglutide (Victoza), and semaglutide (Ozempic).
- SGLT2 inhibitors. These help your kidneys filter out more glucose. You might get canagliflozin (Invokana), dapagliflozin (Farxiga), or empagliflozin (Jardiance). Empagliflozin has also proven effectibve in reducing the risk of hospitalization or death from heart failure.
- GIP and GLP-1 receptor agonist. Tirzepatide (Mounjaro) is the first in its class and activates both the GLP-1 and GIP receptors, which leads to improved blood sugar control.
- Insulin. You might take long-lasting shots at night, such as insulin detemir (Levemir) or insulin glargine (Lantus).
Even if you change your lifestyle and take your medicine as directed, your blood sugar may still get worse over time. That doesn’t mean you’ve done something wrong. Diabetes is progressive, and many people eventually need more than one drug.
When you take more than one drug to control your type 2 diabetes, that’s called combination therapy.
You and your doctor should work together to find the best mix for you. Usually, you'll keep taking metformin and add something else.
What that is may depend on your situation. Some drugs control blood sugar spikes (your doctor may call this hyperglycemia) that come right after meals, for instance. Others are more effective at stopping drops in blood sugar (hypoglycemia) between meals. Some may help with weight loss or cholesterol, as well as your diabetes.
You and your doctor should talk about any possible side effects. Cost may be an issue as well.
If you take medication for something else, that will need to be factored into any decision.
You’ll need to see your doctor more often when you start taking a new combination of drugs.
You might find that adding a second drug doesn’t bring your blood sugar under control. Or the combination of two drugs might work only for a short time. If that happens, your doctor might consider a third noninsulin drug, or you may start insulin therapy.
Type 2 Diabetes Prevention
Adopting a healthy lifestyle can help you lower your risk of diabetes.
- Lose weight. Dropping just 7% to 10% of your weight can cut your risk of type 2 diabetes in half.
- Get active. Thirty minutes of brisk walking a day will cut your risk by almost a third.
- Eat right. Avoid highly processed carbs, sugary drinks, and trans and saturated fats. Limit red and processed meats.
- Quit smoking. Work with your doctor to keep from gaining weight after you quit, so you don't create one problem by solving another.
Type 2 Diabetes Complications
Over time, high blood sugar can damage and cause problems with your:
- Heart and blood vessels. You’re up to five times more likely to get heart disease or have a stroke. You’re also at high risk of blocked blood vessels (atherosclerosis) and chest pain (angina).
- Kidneys. If your kidneys are damaged or you have kidney failure, you could need dialysis or a kidney replacement.
- Eyes. High blood sugar can damage the tiny blood vessels in the backs of your eyes (retinopathy). If this isn’t treated, it can cause blindness.
- Nerves. This can lead to trouble with digestion, the feeling in your feet, and your sexual response.
- Skin. Your blood doesn’t circulate as well, so wounds heal slower and can become infected.
- Pregnancy. Women with diabetes are more likely to have a miscarriage, a stillbirth, or a baby with a birth defect.
- Sleep. You might develop sleep apnea, a condition in which your breathing stops and starts while you sleep.
- Hearing. You’re more likely to have hearing problems, but it’s not clear why.
- Brain. High blood sugar can damage your brain and might put you at higher risk of Alzheimer’s disease.
- Depression. People with the disease are twice as likely to get depressed as people who don’t have it.
The best way to avoid these complications is to manage your type 2 diabetes well.
- Take your diabetes medications or insulin on time.
- Check your blood sugar.
- Eat right, and don't skip meals.
- See your doctor regularly to check for early signs of trouble.
Build Your Health Care Team
There are many medical professionals who can help you live well with diabetes, including:
- Registered dietitians
- Diabetes educators
- Foot doctors
- Eye doctors
10 Questions to Ask Your Doctor About Diabetes
If you were recently diagnosed with type 2 diabetes, ask your doctor these questions at your next visit.
- Does having diabetes mean that I am at higher risk for other medical problems?
- Should I start seeing other doctors regularly, such as an eye doctor?
- How often should I test my blood sugar, and what should I do if it is too high or too low?
- Are there any new medications that I could use to help manage my diabetes?
- Does diabetes mean I have to stop eating the foods I like best?
- How can exercise make a difference in my diabetes?
- If I'm overweight, how many pounds do I have to lose to make a difference in my health?
- Are my children at increased risk for the disease?
- What is the importance of diet in diabetes?
- Do I need to take my medications even on days that I feel fine?