Type 2 Diabetes

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What is type 2 diabetes?

Diabetes is a metabolic condition that affects about 10.5% of the U.S. population—more than 34 million people have the disease in the United States. Of those people, about 95% have type 2 diabetes and the rest have type 1 diabetes. Without treatment, the hallmark symptoms of diabetes are excessive hunger, thirst and urination. Once diagnosed, lifestyle changes and medication for type 2 diabetes relieves symptoms. See your doctor as soon as possible if you have these symptoms or notice them in your child.

Type 1 vs. type 2 diabetes

In the past, type 2 diabetes was called adult-onset diabetes. The name seemed appropriate because most people who develop the disease are well into adulthood. As obesity became an epidemic in the United States, type 2 diabetes started showing up at earlier and earlier ages. Today, even children can develop type 2 diabetes, though it is far more common in adults. A better way to compare type 1 vs. type 2 diabetes is to look at the underlying biology.

Type 2 diabetes starts with insulin resistance—a condition in which your cells do not respond normally to insulin. Insulin is a hormone your body needs to use sugar from food for energy. At first, your pancreas—the organ that makes insulin—makes more and more insulin. It is responding to signals that the cells need insulin, even though they aren’t able to use it. Eventually, the pancreas can’t keep up and it stops working the way it should. Blood sugar levels start to rise higher and higher, resulting in hyperglycemia. In type 1 diabetes, blood sugar levels rise because the pancreas stops producing insulin due to an autoimmune attack on insulin-producing cells.

Diabetes causes sugar (glucose) to accumulate to unhealthy levels in your bloodstream. With time, uncontrolled high blood sugar can cause serious health problems, including:

  • Heart disease
  • Stroke
  • Kidney damage and failure
  • Vision problems including blindness

Getting screened for type 2 diabetes regularly can help you catch it before you have major problems.

What are the symptoms of type 2 diabetes?

The process of insulin resistance and pancreas burnout typically happens gradually. As a result, symptoms tend to develop slowly as well. In fact, you may not realize you have type 2 diabetes for many years.

Common symptoms of type 2 diabetes

The most common type 2 diabetes symptoms include:

  • Being constantly thirsty or hungry
  • Being tired or weak all the time
  • Feeling tingling or other abnormal sensations in the hands or feet
  • Having problems with your vision
  • Having wounds or sores that won’t heal
  • Needing to urinate frequently

You may also experience frequent infections, including yeast infections and other fungal infections. Sometimes, type 2 diabetes causes ED (erectile dysfunction) in men.

Serious symptoms that might indicate a life-threatening condition

It is possible for blood sugar to rise so high that it becomes a life-threatening condition. This is ketoacidosis. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

  • Fruity or sweet-smelling breath

Regular screening for type 2 diabetes can help you catch it before major problems develop. A simple blood test at your annual exam can give your doctor information about your blood sugar. However, if you notice symptoms between regular exams, be sure to schedule an appointment with your doctor.

What causes type 2 diabetes?


While doctors understand how type 2 diabetes develops, it is less clear what causes insulin resistance to begin. It is likely a combination of genetic and environmental factors. It is possible that some people are more prone to developing the disorder based on their genes. However, health experts also know that inactivity and excess weight can trigger type 2 diabetes.

What are the risk factors for type 2 diabetes?

Several factors increase the risk of developing type 2 diabetes. However, not all people with risk factors will end up with the disease.

Type 2 diabetes risk factors include:

  • Family history of type 2 diabetes in a parent or sibling
  • High cholesterol

  • History of gestational diabetes with a previous pregnancy
  • History of polycystic ovary syndrome (PCOS)

  • Lack of regular exercise
  • Older age, especially being over 45 years
  • Overweight and obesity, especially with a fat distribution around the abdomen

  • African American, Asian American, Hispanic American, Native American, and Pacific Islander ethnicity

How do you prevent type 2 diabetes?

Reducing your risk of type 2 diabetes may be possible by living a healthy lifestyle and treating other type 2 diabetes risk factors. You may be able to lower your risk of type 2 diabetes by:

  • Eating a healthy diet low in fat and calories and high in lean protein, fiber, whole grains, and fresh fruits and vegetables
  • Getting regular physical exercise with 30 minutes of moderate activity per day

  • Losing excess weight (if you are overweight) by shedding 5 to 10% of your body weight

  • If you have prediabetes or insulin resistance, taking medicine prescribed for those conditions (along with lifestyle changes as necessary)

It’s important to see your doctor before making dramatic lifestyle changes. Your doctor can help you develop realistic and healthy goals. These changes can be challenging. You can find support through your doctor if you struggle with making changes that will improve your health.

What are some conditions related to type 2 diabetes?

Type 2 diabetes is a metabolic disorder. There are several metabolic and endocrine conditions related to type 2 diabetes and which increase the risk of developing type 2 diabetes, including:

  • Insulin resistance, a metabolic condition in which fat, muscle and liver cells do not function normally in response to insulin, causing the pancreas to make more insulin. Insulin resistance can eventually lead to high blood sugar and type 2 diabetes.
  • Polycystic ovary syndrome, a condition caused by a hormone imbalance. Ten to 20% of women with PCOS will develop type 2 diabetes.
  • Prediabetes, a condition marked by higher than normal blood glucose levels, but not high enough to diagnose type 2 diabetes

How do doctors diagnose type 2 diabetes?

Doctors diagnose type 2 diabetes based on how much glucose (sugar) is in your blood. If your doctor suspects you have diabetes, additional blood tests can determine if it is type 1 or type 2 diabetes.

Type 2 diabetes tests include:

  • Fasting blood glucose. For a fasting test, your blood is checked after fasting for eight hours. The normal fasting blood glucose level is typically less than 100 mg/dL in someone without diabetes or prediabetes. You may have diabetes if your fasting blood glucose is 126 mg/dL or higher.
  • Random blood glucose. You can have this test at any time without fasting beforehand. The normal blood glucose level is normally less than 140 mg/dL. A value of 200 mg/dL indicates diabetes.
  • Oral glucose tolerance test. After fasting overnight, you drink a sugary liquid. A blood sample is taken at different times after you finish the drink. You may have this test the same day as the fasting blood glucose test. People without diabetes or prediabetes will have a value of less than 140 mg/dL. A value of 200 mg/dL or higher indicates diabetes.
  • Glycated hemoglobin (HbA1C) test. Also known as A1C, this test tells you about your blood glucose control over the last 2 to 3 months. It measures the amount of sugar-modified hemoglobin in the blood. The average A1C is normally less than 5.7%. An A1C of 6.5% or higher from two separate tests is diabetes. (There are some situations, such as recent blood loss or pregnancy, where A1C is not a good indicator of diabetes.)

How is type 2 diabetes treated?


The goal of type 2 diabetes treatment is getting blood sugar levels as close as possible to normal. In most cases, target blood sugar levels are between 80 and 130 mg/dL. Your doctor may adjust this target and will give you other targets, including after meal blood sugar levels and HbA1C levels. HbA1C shows how well your blood sugar has been controlled over the last 2 to 3 months. For most people, this means an HbA1C of 7%.


Some people can accomplish blood sugar control through the same lifestyle changes that help reduce the risk of type 2 diabetes—diet, exercise, and weight loss. However, many people with the disease need to add medicine to these lifestyle changes to reach their treatment goals. Both oral and injectable medicines are available to treat type 2 diabetes.

Oral medication for type 2 diabetes

Type 2 diabetes oral medicines include:

  • Alpha-glucosidase inhibitors, which slow the digestion of carbohydrates, starches and sugars, leading to more even and constant blood sugar levels after meals
  • Biguanides, which make your cells more sensitive to insulin and decrease the amount of sugar coming from your liver between meals or for quick energy boosts
  • DPP-4 inhibitors, which boost incretin—a hormone that helps lower blood sugar levels only when they are high—resulting in modest blood sugar lowering without hypoglycemia (low blood sugar)
  • Meglitinides, which stimulate the pancreas to release insulin
  • SGLT2 inhibitors, which allow your body to get rid of extra glucose (sugar) in the urine instead of reabsorbing it
  • Sulfonylureas, which also stimulate the pancreas to release insulin
  • Thiazolidinediones, which increase insulin sensitivity in your cells and decrease glucose coming from your liver

Injectable medications for type 2 diabetes


Type 2 diabetes injectable medicines include:

  • Amylin analogs, which mimic a hormone called amylin that keeps glucose levels from going too high after meals
  • GLP-1 agonists, which mimic another hormone, glucagon-like peptide-1, to regulate blood glucose after meals and decrease appetite
  • Insulin, which replaces the insulin your body would normally make

Blood sugar monitoring will be part of your diabetes treatment plan. How often you need to check your blood sugar levels will depend on the type of treatment you use. In general, people on oral medicines will check it a few times a day. People using insulin will need more frequent monitoring.


Other strategies for type 2 diabetes management

Other strategies to help control your blood sugar include:

  • Meal and snack planning
  • Regular exercise
  • Stress management
  • Weight loss

What are the diet and nutrition tips for type 2 diabetes?

A healthy diet and nutrition are a cornerstone of managing type 2 diabetes. In fact, some people can even reverse the diagnosis if they can follow a strict diet and exercise plan. Type 2 diabetes increases the risk of heart disease and stroke, so following a heart-healthy diet is the simplest way to approach eating and nutrition for type 2 diabetes. If you do not already have a healthy eating plan, a diabetes dietitian can help you. (Many insurance plans, including Medicare Part B, cover medical nutrition therapy for diabetes.)

Here are some general tips for what and how much to eat:

  • Dairy: Choose low-fat over “full-fat” versions of milk, yogurt and cheese.
  • Fats and oils: Substitute saturated fats, mayonnaise, dressings and creams for healthy oils (like olive oil and safflower oil) and homemade dressings and spreads.
  • Fruit: Fresh, whole fruit is best. If you buy canned fruit, choose a variety that has no added sugar.
  • Meat and other protein sources: Choose low-fat cuts of beef and skinless poultry, small portions, and do not fry the food—including tofu. Eggs are great sources of protein too, unless you are vegan.
  • Starch: This is cereal, bread, potatoes, corn and others. They contain carbohydrates, which are broken down into sugar. So, this is the category of food that is most important to modify. Choose whole grain cereals, pastas and breads and sweet potatoes vs. regular potatoes.
  • Sweets: Swap out cakes, cookies and ice cream for berries, low-sugar and low-fat desserts; choose smaller portions.
  • Vegetables: Most anything goes here, except for starchy veggies. Eat raw or steamed, or sauté them in a healthy cooking oil.

How does type 2 diabetes affect quality of life?

Any health condition, especially a chronic one, can have a negative impact on quality of life—which is defined by physical, mental and social health and function. Simply being diagnosed with type 2 diabetes or prediabetes can reduce quality of life, based on patients’ answers to quality of life questionnaires.

Factors affecting quality of life, summarized from a T2D Lifestyle survey include:

  • Complications of diabetes, including heart disease, kidney disease, and limb amputation, as well as fear of complications
  • Financial burden of paying for diabetes medications
  • Loneliness
  • Managing type 2 diabetes
  • Sleep disorders

Your healthcare team can support you and help you set realistic goals for a healthy life with type 2 diabetes. Supportive friends and family can also reassure you and are pivotal to your success, but you are the most important part of the solution. Learning how to take care of yourself is the real key to staying healthy with type 2 diabetes.

Here are some tips for living with type 2 diabetes:

  • Get all recommended screenings and vaccinations
  • Join a support group
  • Keep your appointments
  • Know what to do when you are sick or have blood sugar that is too low (hypoglycemia)
  • Learn how to take care of your feet
  • Reward yourself with non-food rewards
  • Use setbacks as a chance to learn and don’t let them discourage you

What are the potential complications of type 2 diabetes?

With type 2 diabetes, there are a variety of possible complications of the disease and its treatment. Of them, hypoglycemia, or low blood sugar, is one of the most common. Hypoglycemia means your blood sugar has fallen below your target range. It’s a common side effect of several medicines for type 2 diabetes, including insulin, meglitinides and sulfonylureas.


Signs of a potential problem with low blood sugar include:

  • Hunger or nausea

These symptoms should be a warning sign to check your blood sugar. If it is low, you need to take a quick source of sugar. Glucose tablets are a good choice, but there are other options. This includes sugar, honey, and fruit juice. Left untreated, hypoglycemia can be life-threatening. Seek immediate medical care (call 911) if someone with diabetes has low blood sugar symptoms that aren’t responding to treatment or if they have fainted or lost consciousness.


The other potential complications of type 2 diabetes are the result of chronically high blood sugar levels. When blood sugar remains high and uncontrolled, it damages nerves, blood vessels, and other tissues. Complications that can develop from this include heart disease, stroke, kidney damage, neuropathy, and eye, hearing, foot and skin problems. In addition, uncontrolled blood sugar can increase your risk of Alzheimer’s disease. You can protect yourself against these complications by following your treatment plan and healthy living habits.

Does type 2 diabetes shorten life expectancy?

People with type 2 diabetes who can control their blood sugar levels have an excellent prognosis. On average, life expectancy is up to two years less than someone of the same age and sex without type 2 diabetes, using United Kingdom data sources.

The same study showed that blood glucose control over time improved life expectancy. One measure of blood glucose control is the A1C, or glycated hemoglobin (HbA1C) test. It represents the amount of a modified form of hemoglobin. For someone without diabetes, the average A1C is typically less than 5.7%. People with diabetes will have an A1C of 6.5% or higher. The U.K. study found that each year with an A1C greater than 7.5% was equivalent to losing 100 days of life, for people with type 1 or type 2 diabetes. (Most treatment guidelines recommend achieving an A1C at or below 7%.)

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Apr 12
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Centers for Disease Control and Prevention. National Diabetes Statistics Report, 2020. Atlanta, GA: Centers for Disease Control and Prevention, U.S. Dept of Health and Human Services; 2020.
  2. Hyperglycemia (High Blood Sugar). American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hyperglycemia.html
  3. Hypoglycemia (Low Blood Sugar). American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hypoglycemia-low-blood.html
  4. Insulin and Other Injectables. American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/medication/insulin/
  5. Who’s at Risk? Centers for Disease Control and Prevention. https://www.cdc.gov/diabetes/basics/risk-factors.html
  6. Diabetes Related Conditions. Diabetes UK, The British Diabetic Association. https://www.diabetes.org.uk/diabetes-the-basics/related-conditions
  7. Facts About Type 2. American Diabetes Association. http://www.diabetes.org/diabetes-basics/type-2/facts-about-type-2.html
  8. Insulin, Medicines, & Other Diabetes Treatments. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/diabetes/overview/insulin-medicines-treatments
  9. Type 2 Diabetes. American Diabetes Association. http://www.diabetes.org/diabetes-basics/type-2/?loc=db-slabnav
  10. Type 2 Diabetes. Centers for Disease Control and Prevention. https://www.cdc.gov/diabetes/basics/type2.html
  11. Type 2 Diabetes. Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/symptoms-causes/syc-20351193
  12. What Is Diabetes? National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes
  13. Heald, Adrian H.a,,b; Stedman, Mikec; Davies, Markc; Livingston, Markd; Alshames, Ramadanb; Lunt, Marke; Rayman, Gerryf; Gadsby, Rogerg Estimating life years lost to diabetes: outcomes from analysis of National Diabetes Audit and Office of National Statistics data, Cardiovascular Endocrinology & Metabolism: December 2020 - Volume 9 - Issue 4 - p 183-185 doi: 10.1097/XCE.0000000000000210. Retrieved from https://journals.lww.com/cardiovascularendocrinology/Fulltext/2020/12000/Estimating_life_years_lost_to_diabetes__outcomes.9.aspx
  14. Complications of type 2 diabetes affect quality of life, care can lead to diabetes burnout. EurekaAlert! https://www.eurekalert.org/pub_releases/2016-12/hu-cot113016.php
  15. The Complexities of Type 2 Diabetes Complications. Type2Diabetes.com. https://type2diabetes.com/infographic/complexities-complications