Type 2 Diabetes

Medically Reviewed on 2/23/2023

What is type 2 diabetes?

Type 2 diabetes symptoms can be managed by diligently controlling blood sugar levels.
Type 2 diabetes symptoms can be managed by diligently controlling blood sugar levels.

Type 2 diabetes is the most common type of diabetes. It is a chronic condition in which blood glucose (sugar) can no longer be regulated. There are two reasons for this. First, the cells of the body become resistant to insulin (insulin resistant). Insulin works like a key to let glucose (blood sugar) move out of the blood and into the cells where it is used as fuel for energy. When the cells become insulin resistant, moving sugar into the cells requires more and more insulin, and too much sugar stays in the blood. Over time, if the cells require more and more insulin, the pancreas can't make enough insulin to keep up and begins to fail.

What causes type 2 diabetes?

Type 2 diabetes can be reversed with diligent attention to changing lifestyle behaviors. Type 2 diabetes is caused by a combination of genetics and unhealthy lifestyle habits. The exact causes of type 2 diabetes are not fully understood, but there are several risk factors that can increase your likelihood of developing the condition. These include:

  • Some ethnic groups have a higher inherited incidence of it. African Americans, Latinos, Native Americans, Asian Americans, and Pacific Islanders are all at increased risk.
  • Age: The risk of developing type 2 diabetes increases as you get older, particularly after the age of 45.
  • Family history: If you have a parent or sibling with type 2 diabetes, you are more likely to develop the condition.
  • Obesity: Being overweight or obese is a significant risk factor for type 2 diabetes, as excess body fat can make the body less sensitive to insulin.
  • High blood pressure and high cholesterol: Having high blood pressure or high cholesterol can increase the risk of developing type 2 diabetes.
  • Gestational diabetes: Women who develop gestational diabetes during pregnancy are at a higher risk of developing type 2 diabetes later in life.
  • Other causes include unhealthy lifestyle habits, for example, if you:

Who gets type 2 diabetes?

Risk factors for type 2 diabetes are:

  • Age (being over age 45)
  • A family history of diabetes
  • Being of a race or ethnic group with a genetic predisposition for this type of diabetes
  • Being overweight
  • Having had prediabetes or gestational diabetes
  • Having other metabolic syndrome conditions such as high blood pressure, low HDL or "good" cholesterol, or high triglycerides

What lifestyle factors affect my chances of getting this type of diabetes?

Lifestyle habits can contribute to a person developing the disease, for example:

  • If you are overweight or obese
  • If you are sedentary (you don't exercise and are not physically active)
  • If you watch more than 2 hours of TV per day
  • If you drink artificially sweetened or sugar-sweetened products. These products increase your risk by 26%-67%.
  • Economic stress. People who live in the lowest-income circumstances have a 2 1/2 times greater risk of developing the disease.


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What are the signs and symptoms of type 2 diabetes?

This type of diabetes develops gradually, over years, so the signs and symptoms can seem subtle, and you might think it is something you "just have to live with." If you are overweight or obese, this is the major symptom, but not everyone will be overweight. In fact, weight loss can be a symptom.

Other symptoms and signs include:

  1. Fatigue
  2. Frequent urination
  3. Excess thirst
  4. Blurry or cloudy vision
  5. Wounds that won't heal
  6. Tingling or numbness in the feet
  7. Erectile dysfunction (ED)
  8. Dark skin under the armpits and around the groin

What are the symptoms of low and high blood sugar in type 2 diabetes?

Type 2 diabetes is a condition of blood sugar dysregulation. In general blood sugar is too high, but it also can be too low. This can happen if you take your diabetes medications and then skip a meal. Blood sugar also can rise very quickly after a high glycemic index meal, and then fall a few hours later, plummeting into hypoglycemia (low blood sugar). The signs and symptoms of low blood sugar (hypoglycemia) can include

  • Feeling dizzy or light-headed
  • Difficulty concentrating or making decisions
  • Feeling sweaty or clammy
  • Hunger
  • Pale skin
  • Rapid heartbeat
  • Anxiety or nervousness
  • Vision changes, like blurring or narrowing of the visual field
  • Feeling physically weak
  • Feeling sleepy
  • Feeling irritable

High blood sugar (hyperglycemia) is common in type 2 diabetes. Its signs and symptoms can be either acute (short in duration) or chronic (last over a long period of time).

Acute symptoms include:

  • Feeling tired
  • Feeling vision is blurry or foggy
  • Frequent urination
  • Feeling very thirsty
  • Fatigue or weakness
  • Confusion or difficulty concentrating
  • Rapid hearbeat
  • Headache
  • Dry or flushed skin

Chronic signs and symptoms can include:

  • Darkening skin under armpits, neck, thighs
  • Fungal infections on the skin like ringworm or toenail fungus
  • Weight gain
  • Difficulty with sexual function
  • Numbness, tingling, or burning sensations in the feet

It's important to note that some people with type 2 diabetes may not experience any symptoms of high or low blood sugar, which is why regular monitoring of blood sugar levels is essential for managing the condition.

What is the difference between type 1 and type 2 diabetes?

Type 2 diabetes, also known as non-insulin dependent diabetes or adult-onset diabetes, is a metabolic disorder that develops when the body becomes resistant to insulin or the pancreas does not produce enough insulin to regulate blood sugar levels. 

  • If you have type 2, you can lower high blood sugar levels with diet, exercise, and oral drugs that either make the body more sensitive to insulin or help the pancreas release more insulin.
  • Type 2 diabetes is most commonly diagnosed in middle-aged and older adults, but it can also occur in younger people, particularly those who are overweight or obese. 
  • Over time, people with type 2 also can require insulin. This happens when the pancreas "wears out."

In type 1 diabetes, the pancreas cannot make any insulin, and people have to depend on insulin injections to lower blood sugar. It is an autoimmune disease in which the body's immune system attacks and destroys the cells in the pancreas that produce insulin. This results in a severe deficiency of insulin, which leads to high blood sugar levels.

  • Type 1 diabetes typically develops in childhood or early adulthood and requires lifelong insulin therapy to manage blood sugar levels.

Other differences between type 1 and type 2 diabetes include:

  • Symptoms: The symptoms of type 1 and type 2 diabetes are similar, including increased thirst and urination, fatigue, and blurred vision.
    • Type 1 diabetes often presents with more severe symptoms and more rapid onset.
    • Type 2 diabetes may develop slowly over time.
  • Risk factors: The causes and risk factors include:
    • While the exact causes of type 1 diabetes are not fully understood, it is believed to be caused by a combination of genetic and environmental factors.
    • Type 2 diabetes, on the other hand, is largely influenced by lifestyle factors such as obesity, physical inactivity, and poor diet.
  • Treatment: Type 1 and type 2 diabetes differences include: 
    • Type 1 diabetes requires lifelong insulin therapy to manage blood sugar levels.
    • Type 2 diabetes can often be managed through lifestyle changes and medication, with insulin therapy reserved for more severe cases.

Diagnosis of type 2 diabetes

Adult and pediatric endocrinologists, specialists in treating hormone imbalances and disorders of the endocrine system, are experts in helping patients with diabetes manage their disease. People with the disease also may seek care from a number of primary care providers including

  • family or internal medicine practitioners,
  • naturopathic doctors, or
  • nurse practitioners.

When complications arise, these patients often consult other specialists, including

  • neurologists,
  • gastroenterologists,
  • ophthalmologists,
  • acupuncturists,
  • surgeons, and
  • cardiologists.
  • Nutritionists, integrative and functional medicine doctors, and
  • physical activity experts such as personal trainers are also important members of a diabetes treatment team.

It is important to interview new healthcare professionals about their experience, expertise, and credentials to make sure they are well qualified to help you.

There is a blood test to diagnose type 2 diabetes. The blood is tested for glucose and the result is the following:

  • If it is greater than 125 fasting, or more than 200 when randomly tested, the diagnosis is diabetes.
  • If the fasting blood sugar is between 100-125, the person has a diagnosis of prediabetes.

Tests also can measure average blood sugar (hemoglobin A1c) over time.

  • A hemoglobin A1c (HbA1c) test greater than 6.5% indicates the diagnosis of the disease.
  • Prediabetes is diagnosed with an HbA1c of 5.7% - 6.4%.

What is the treatment for type 2 diabetes?

Treatment for this type of diabetes can include:

Not all people with diabetes need drug therapy. A healthy eating plan and exercise alone can be enough if the person makes significant lifestyle changes. Other signs, symptoms, and complications also may need treatment. For example, nutritional deficiencies should be corrected, heart or kidney disease may need to be treated, and vision must be checked for eye problems like diabetic retinopathy.

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What medications treat type 2 diabetes?

There are different types of diabetes drugs. They work in different ways to either stop the liver from making glucose, make the pancreas release more insulin, or block glucose from being absorbed. Insulin replaces the natural insulin when the pancreas can't make it any longer.

Metformin (Glucophage, Glucophage XR, Glumetza, Fortamet, Riomet)

Metformin (Glucophage, Glucophage XR, Glumetza, Fortamet, Riomet) belongs to a class of drugs called biguanides. Metformin is the first-line therapy for most type 2 diabetics. It works to stop the liver from making excess glucose and has a low risk of hypoglycemia. Hypoglycemia or very low blood sugar can cause symptoms such as sweating, nervousness, heart palpitations, weakness, intense hunger, trembling, and problems speaking. Many patients lose some weight by taking metformin, which is also helpful for blood sugar control.

Sulfonureas and meglitinides

Sulfonureas and meglitinides are classes of drugs also prescribed for treatment. These drugs cause the pancreas to release more insulin. Since the pancreas can only work so hard, these drugs have a limited duration of usefulness.

The sulfonureas include:

The meglitinides include:

Canagliflozin (Invokana) and dapagliflozin (Farxiga)

Canagliflozin (Invokana) and dapagliflozin (Farxiga) are oral medications prescribed to treat type 2 diabetics. These drugs belong to the drug class referred to as sodium-glucose co-transporter 2 (SGLT2) inhibitors. These drugs work by stopping the absorption of glucose in the kidneys, enabling some of it to be urinated out.

Another type 2 diabetes medications

There are other oral and injectable drugs for patients with type 2 diabetics such as:

For people who want to avoid drugs, taking an aggressive approach to a healthy eating plan and lifestyle change is an option. It isn't easy, but if someone is very committed and motivated, lifestyle changes can be enough to maintain a healthy blood sugar level and lose weight. Learning about a healthy diabetes diet (a low-glycemic load diet) can be a good place to start.

Do people with type 2 diabetes have to take insulin?

Insulin is only recommended for individuals with type 2 diabetes when they have not been able to get blood sugars low enough to prevent complications through other means. To avoid insulin, those with this health condition should work very hard to follow a healthy eating plan that includes a lot of vegetables and lean proteins, exercise every day, and keep stress in perspective.

They also should take their oral drugs regularly. It can be difficult to follow these recommendations and the help of your doctor, nutritionist, diabetes educator, health coach, or integrative medicine practitioner may be helpful. If you want to avoid taking medicine, work with health professionals who are knowledgeable about lifestyle medicine and can help you understand how to fit the changes into your life.

Is there a type 2 diabetes diet plan?

If you have this type of diabetes, the foods you eat should have a low-glycemic load (index) -- foods higher in fiber, protein, or fats -- like vegetables and good quality protein such as fish, chicken, beans, and lentils. From that base, add other types of nutritious foods like fruit, whole grains, low-fat dairy products, and nuts.

Avoid foods with a high glycemic index (foods that raise blood sugar too quickly) such as processed foods, and foods high in carbohydrates, sugars, or animal fat. Examples of foods to avoid include:

  • Desserts
  • Sweets
  • Pastries
  • Bread
  • Chips
  • Crackers
  • Pasta

A good rule of thumb is to avoid white foods (except for cauliflower!).

Can exercise help manage type 2 diabetes?

Exercise is very important if you have this health condition. Exercise can be an effective way to help manage type 2 diabetes. Regular physical activity can help improve insulin sensitivity, allowing the body to use insulin more effectively to regulate blood sugar levels.

  • Exercise makes cells more insulin-sensitive, pulling glucose out of the blood. This brings down blood sugar, and more importantly, gives you better energy because the glucose is being transferred to the cells.
  • Any type of exercise will do this, but you gain extra benefit when the activity helps build muscle, such as weight training or using resistance bands.
  • Exercise can also help lower blood pressure and cholesterol, and reduce the risk of heart disease, which is a common complication of diabetes.
  • The benefits of exercise on blood sugar last about 48-72 hours, so you need to be physically active almost every day.

What are the complications of type 2 diabetes?

If blood sugar is not controlled over time, complications can develop. These include:

If you have diabetes, you have a higher risk of heart disease and heart attack. Because of this, it is important to control cholesterol and high blood pressure in addition to blood sugar. The good news is that all of these diseases are responsive to healthy lifestyle changes.

What is life expectancy for someone with type 2 diabetes?

  • Some research shows that people with type 2 diabetes may die 10 years earlier than those without diabetes.
  • Most people with the disease die of secondary complications of it, for example, kidney failure or heart disease.
  • However, with good blood sugar control and healthy lifestyle choices, complications can be prevented.

Can type 2 diabetes be prevented?

A healthy lifestyle can prevent almost all cases of type 2 diabetes. A large research study called the Diabetes Prevention Program found that people who made intensive lifestyle changes including

  • Diet and exercise reduced their risk of developing diabetes by 58%.
  • Those over 60 years old seemed to experience extra benefits; they reduced their risk by 71%.
  • In comparison, people who were given the drug metformin for diabetes prevention only reduced their risk by 31%.

What if I have type 2 diabetes and become pregnant?

If you are a diabetic and are pregnant you can have a normal, healthy pregnancy, but you need to take extra steps to avoid gaining excess weight and high blood sugars. Lifestyle habits (eating primarily vegetables and lean protein and exercising every day) will prevent problems during pregnancy.

If you are a diabetic and become pregnant, monitor your blood sugar levels often. Talk with your doctor about exploring additional healthcare professionals, for example, a nutritionist, health coach, or naturopathic doctor about a healthy eating plan. If your blood sugar gets out of control you may:

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Medically Reviewed on 2/23/2023
American Diabetes Association.

NIH. National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes Prevention Program (DPP).