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Reviewed/Revised Mar 2023
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What is diabetes?

Diabetes is a disease in which your blood sugar (glucose) levels are too high.

You get diabetes if your body's normal way of controlling blood sugar isn't working right.

What is blood sugar?

Blood sugar is:

  • Your body’s main source of energy

Blood sugar isn't just from sugar that's in your drinks or that you put on food. Blood sugar comes from all sorts of food, like:

  • Bread

  • Fruit

  • Pasta

  • Potatoes

These and many other foods contain carbohydrates. Your body turns carbohydrates into blood sugar.

How does my body control blood sugar?

Your body controls how much sugar gets from your blood into your body’s cells by using:

  • Insulin

Insulin is a hormone your body makes in the pancreas. The pancreas is an organ in your belly behind your stomach.

After you eat, your body absorbs food and your blood sugar increases. Your pancreas senses the higher blood sugar and starts putting out insulin. The insulin tells your body's cells to take in sugar from the blood. When the blood sugar is at the right level, your pancreas stops putting out insulin.

What causes diabetes?

Diabetes Mellitus

Diabetes involves a problem with insulin.

There are 2 main types of diabetes:

  • In type 1 diabetes, your pancreas doesn't make insulin because the cells that make it were destroyed

  • In type 2 diabetes, your pancreas makes plenty of insulin but your body’s cells don’t respond to the insulin the way they should

Eating sugary foods doesn't give you diabetes. However, eating so much that you get very overweight can give you type 2 diabetes.

Type 1 diabetes usually develops before age 30, typically in children and adolescents.

Type 2 diabetes can develop at any age but is more common in people who:

  • Are overweight or obese

  • Are age 30 or older

  • Have certain racial or ethnic backgrounds (in the United States: people with African American, Asian American, American Indian, Alaskan native, and Spanish or Latin American ancestry are at increased risk)

  • Have family members who have type 2 diabetes

What are the symptoms of diabetes?

Type 1 diabetes symptoms often start suddenly. You may:

  • Urinate (pee) a lot

  • Be very thirsty and drink a lot

  • Have belly pain (especially for children)

  • Eat more than you usually do but still lose weight

  • Have blurry vision

  • Feel sleepy or sick to your stomach

  • Have breath that smells fruity and like nail polish remover

  • Breathe deeply and very fast

  • Feel sick to your stomach and throw up

  • Feel weak and tired all over

Type 2 diabetes symptoms may start slowly. You may not have symptoms for many years. When you do, you may notice you’re:

  • Urinating more often and in larger amounts

  • Drinking a lot more water

These symptoms get worse over weeks or months. You may also:

  • Feel very weak and tired all over

  • Have blurry vision

  • Get dehydrated (not have enough water in your body)

What are the complications of diabetes?

How can doctors tell if I have diabetes?

Doctors will test your blood to check your:

  • Blood sugar levels

Usually doctors measure your blood sugar level first thing in the morning before you've eaten anything. That is called a fasting blood sugar. Doctors need to measure fasting blood sugar because the rest of the day your blood sugar goes up and down depending on how much you eat.

Fasting blood sugar levels:

  • Less than 100 is normal

  • 100 to 125, you're at risk of diabetes

  • 126 or higher, you have diabetes

Another test doctors might do is:

  • Hemoglobin A1C

Hemoglobin is a substance inside your red blood cells. It carries oxygen in your blood. Sugar in your blood attaches to hemoglobin and forms hemoglobin A1C.

  • The higher your blood sugar, the more hemoglobin A1C there is

Because hemoglobin A1C lasts a long time, the amount of it in your blood changes slowly. So your hemoglobin A1C level tells your doctor about your blood sugar levels over the past 2 to 3 months. People with a hemoglobin A1C level higher than 6.5% have diabetes.

How do doctors treat diabetes?

There is no cure for diabetes. The goal of treatment is to keep blood sugar levels close to normal.

  • The better you control your blood sugar levels, the less likely you are to have complications

Treatment of diabetes involves:

  • A proper diet

  • Exercise

  • Losing weight if you're overweight

  • Medicines

  • Checking your blood sugar regularly

If you have diabetes, learn as much about it as you can. Talk to a nurse trained in diabetes education. The nurse can help you understand what to eat, how active to be, how to check your blood sugar levels, and how to adjust your insulin (if needed).

What should I eat?

Your body can't respond to changes in your blood sugar level, so it's important to:

  • Eat meals and snacks at about the same time each day

  • Eat about the same amount each day

  • Limit carbohydrates (like bread) and fatty foods at each meal

  • Eat more vegetables and carbohydrates that break down slowly, like those in fruits, whole grains, and high-fiber foods

  • Limit processed foods, like candy, cookies, donuts, and pastries

  • Avoid sugary drinks, including soda, sweet iced tea, lemonade, fruit punch, and sports drinks

  • Limit alcoholic drinks to 1 per day if you’re female and 2 per day if you’re male

How active should I be?

You should try to exercise some every day.

  • Working out can help you get to or stay at a healthy weight and control your sugar levels

  • Talk to your doctor or nurse to figure out how much you should work out and what kinds of activities are best for you

  • Because your blood sugar level goes down when you exercise, you may need to eat a snack or give yourself less insulin before a long workout

Should I lose weight?

If you have type 2 diabetes, it's very important to try to lose weight if you're overweight.

  • Losing weight will help control your blood sugar

Sometimes, if you lose enough weight you may not need to take medicine.

If you have type 1 diabetes, losing weight doesn't help with your blood sugar levels. But excess weight isn't healthy for anyone.

Why should I check my own blood sugar?

You need to check your blood sugar level because your blood sugar level changes all the time based on:

  • What you eat

  • How active you are

  • Your stress level

  • If you have an infection

  • Medicines you’re taking

  • The time of day

If your blood sugar levels change significantly, you may need to change your diet or the medicine you take.

Your doctor will tell you when and how often to check your blood sugar. If you have type 1 diabetes, you usually need to check your blood sugar several times a day. If you have type 2 diabetes, you can check it less often.

Most often you'll check your blood sugar by:

  • Sticking your fingertip with a small, sharp tool called a lancet to get a drop of blood

  • Putting the drop of blood on a small plastic test strip

  • Putting the test strip in a small machine that reads blood sugar levels

Write down your blood sugar levels each time you check them so you can share the numbers with your doctor. Your doctor will use the numbers to tell you whether to change your medicines or your diet. If you don't check your blood sugar, it can get too high and no one will know.

Some people use a continuous glucose monitoring device—this uses a small sensor placed under your skin that shows the results of your blood sugar levels every few minutes on the screen of a small belt device worn like a cell phone.

Doctors can also check the amount of hemoglobin A1C in your blood every 3 to 6 months. This lets them see how well your blood sugar levels have been controlled over time.

Do I need medicine?

  • If you have type 1 diabetes, you’ll need insulin (shots or inhaler)—you can learn how to change the amount of insulin based on checking your blood sugar levels

  • If you have type 2 diabetes, you’ll need to take medicine by mouth, but you may also need insulin

Where can I get more information about diabetes?

Drugs Mentioned In This Article

Generic Name Select Brand Names
Afrezza, Exubera
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