Type 2 Diabetes

Reviewed on 9/13/2022

Things to Know About Type 2 Diabetes

One type 2 diabetes risk factor is excess fat around the waist.
One type 2 diabetes risk factor is excess fat around the waist.

What Is the Medical Definition of Type 2 Diabetes?

  • Type 2 diabetes is a chronic medical condition that results from an inability of the body to properly use insulin.

What's the Difference Between Type 1 and Type 2 Diabetes?

  • Type 2 diabetes is different from type 1 diabetes, in which the body is unable to produce sufficient levels of insulin.
  • Symptoms of type 2 diabetes include
  • Risk factors for getting type 2 diabetes include
    • genetics (family history),
    • obesity,
    • fatty waistline (apple shape),
    • inactivity, and
    • older age.
  • A fasting blood sugar level of 126 mg/dl or greater on two different days establishes the diagnosis of diabetes.
  • A number of both oral and injectable medications have been developed for treatment of type 2 diabetes.
  • A hemoglobin A1c (HbA1c) level of 6.5% or greater indicates diabetes.

Can You Get Rid of Type 2 Diabetes?

  • In some people, lifestyle changes such as weight loss combined with physical activity are sufficient to control high blood sugar levels or reverse prediabetes.
  • Managing type 2 diabetes includes a healthy eating plan and exercise, as well as medications in many cases.
  • A healthy eating plan and regular physical activity are important components of a type 2 diabetes treatment plan.
  • There is no one recommended "diabetes diet" for all people with type 2 diabetes.
  • Regular physical activity and modest weight loss can help reduce or prevent type 2 diabetes.

How Serious Is Type 2 Diabetes?

Newly Diagnosed With Type 2 Diabetes?

  • Once you’ve been diagnosed with type 2 diabetes, you and your doctor will develop a diabetes management plan. The goals for treating type 2 diabetes include controlling your blood glucose levels, which may require medication in the short and/or long term as well as lifestyle changes. This will help prevent diabetes-related cardiovascular and neurological complications.
  • The other components of the management plan include adhering to a strict diet and losing weight if you are overweight or obese.
  • Starting on a physical activity plan in the form of a regular exercise regimen is the third aspect of treatment.

What Is Type 2 Diabetes?

Type 2 diabetes is the most common form of diabetes mellitus. In type 2 diabetes, there is an elevated level of sugar (glucose) in the bloodstream due to the body's inability to properly respond to insulin (insulin resistance). Insulin is a hormone that allows the body to utilize glucose for energy. Insulin is produced by specialized cells in the pancreas. An elevated level of blood glucose is known as hyperglycemia. The excessive levels of glucose in the blood spill over into the urine, leading to the presence of glucose in the urine (glucosuria).

Type 2 diabetes is an enormous public health problem. It is estimated that about 30.3 million Americans (9.4% of all Americans) have type 2 diabetes. Increasing rates of obesity are thought to be responsible for the increasing incidence of diabetes. Almost 1 in 4 people living with diabetes are thought to be unaware of their condition.

Type 2 diabetes is a chronic condition that arises slowly over time and persists throughout an individual's lifetime. Over time, people with diabetes can develop complications of the disease that lead to damage to multiple organs. Complications of diabetes include

Good control of the disease can minimize the risk of complications.

What Are the Symptoms of Type 2 Diabetes?

Symptoms and signs of type 1 and type 2 diabetes can be similar. Symptoms and signs of poorly controlled diabetes (or undiagnosed diabetes) can include

Other symptoms, while characteristic of the complications that arise from long-term untreated or poorly treated diabetes, maybe the initial symptoms in some people who do not know they have diabetes. These symptoms include

What Causes, and What Are the Risk Factors for, Type 2 Diabetes?

Type 2 diabetes is the result of the body not being able to effectively use insulin, and is referred to as insulin resistance. Because patients with type 2 diabetes can still produce insulin even though the body does not respond properly, blood levels of insulin can become elevated in some people with the condition along with high blood sugar levels. In some, the pancreas may not be able to properly release the insulin that is produced.

Risk factors for type 2 diabetes

  • Genetics is a strong risk factor for the development of type 2 diabetes. Those who have relatives with the condition are at greater risk.
  • Obesity is another major risk factor. There is a direct relationship between the severity of obesity and the likelihood of getting type 2 diabetes. This is also true for children and teens.
  • Distribution of body fat: Storing excess body fat around the waist is linked to a higher risk than storing fat in the hips and thighs.
  • Age is a risk factor for type 2 diabetes. The incidence increases with advancing age. There is an increase in type 2 diabetes with each decade over the age of 40, independent of weight.
  • Ethnicity: Certain racial and ethnic groups are more likely than others to develop type 2 diabetes. In particular, type 2 diabetes is most likely to occur in Native Americans (affecting 20%-50% of the population). It is also more common in African Americans, Hispanics/Latinos, and Asian Americans than in Caucasian Americans.
  • Gestational diabetes: Women who had diabetes during pregnancy (gestational diabetes) are at increased risk for subsequently developing type 2 diabetes.
  • Sleep disorders: Untreated sleep disorders, particularly sleep apnea, are associated with an increased risk for type 2 diabetes.
  • Inactivity: Being physically active decreases the chance of getting type 2 diabetes.
  • Polycystic ovary syndrome (PCOS): Women with this condition have an increased likelihood of developing type 2 diabetes.

What Is the Difference Between Type 1 and Type 2 Diabetes?

Elevated blood sugar (hyperglycemia) is the hallmark of both type 1 and type 2 diabetes. Type 1 diabetes results from an autoimmune reaction of the body against the insulin-producing beta cells of the pancreas. The pancreas is then unable to produce sufficient insulin. In contrast, patients with type 2 diabetes can produce insulin, but the body is unable to respond properly to the insulin (known as insulin resistance).

  • Type 1 diabetes more commonly affects young people (under 30), and it was formerly referred to as juvenile diabetes and insulin-dependent diabetes because patients with this condition must be treated with insulin.
  • Type 2 diabetes was formerly known as adult-onset diabetes or non-insulin-dependent diabetes.
  • About 10% of people with diabetes have type 1 diabetes while the remainder has type 2 diabetes.
  • While type 1 diabetes typically begins in younger people, some adults experience the late onset of type 1 diabetes (latent autoimmune diabetes in adults, or LADA), and children and adolescents can develop type 2 diabetes.

What Type of Doctor Treats Type 2 Diabetes?

Endocrinologists are the medical specialists who manage problems with hormones and glands. In many cases endocrinologists manage patients with diabetes. In other cases, primary care providers (including internists and family practice specialists), treat type 2 diabetes.

How Is Type 2 Diabetes Diagnosed?

A fasting blood glucose measurement (fasting blood sugar test) is the preferred way to diagnose diabetes.

  • A sample of blood is analyzed after a period of at least 8 hours of fasting. Typically, these measurements are taken in the morning prior to breakfast. Normal values for fasting glucose are less than 100 mg/dl.
  • Having fasting blood glucose levels of 126 mg/dl or greater on two or more tests on different days confirms the presence of diabetes.
  • A random (non-fasting) blood glucose test can also be used to diagnose diabetes. A non-fasting blood glucose level of 200 mg/dl or higher indicates diabetes.

Other tests may also be performed such as:

  • The oral glucose tolerance test (OGTT) involves a series of blood glucose measurements taken at intervals after the consumption of a sugary solution. This test is no longer commonly used to diagnose type 2 diabetes, but it is often used to establish a diagnosis of gestational diabetes.
  • The hemoglobin A1c (HbA1c, glycated hemoglobin) test is a blood test that measures hemoglobin that is bound to blood sugar. This test is indicative of the blood glucose levels over the past 3 months and is often measured in people with diabetes to determine the extent of disease control. An HbA1c level of 6.5% or higher is indicative of diabetes.

What Is the Treatment for Type 2 Diabetes?

The goal (and essential parts) of a treatment plan for type 2 diabetes is to

  1. maintain blood glucose levels under control to prevent complications of the disease,
  2. maintain a healthy weight, and
  3. get regular physical activity.

In some people, weight loss combined with physical activity is sufficient to control blood sugar levels. Other people will require medications for optimum control of their diabetes. The next sections of this article will discuss medications available to treat type 2 diabetes and a well-balanced diabetes diet.

Is There a Type 2 Diabetes Diet or Meal Plan?

A healthy eating plan is an essential part of any diabetes treatment plan, but there is no one recommended "diabetic diet" for everyone. An individual nutrition plan will depend on many things, including underlying health and level of physical activity, the types of medication(s) being taken, and personal preference. Most people with type 2 diabetes find that having a fairly regular schedule for meals and snacks is helpful. Eating a variety of foods and watching portion sizes are also recommended.

Examples of meal planning tools that some people with type 2 diabetes like to use include

  • the plate method,
  • carbohydrate counting, or the
  • glycemic index.

The Plate Method Diet Tool for Type 2 Diabetes

The plate method for meal planning assumes that half of one's plate will be filled with non-starchy vegetables like

  • greens,
  • tomatoes,
  • cauliflower,
  • broccoli,
  • carrots, or
  • turnips.

The remaining half of the plate is divided into three sections.

1. One of these three smaller sections should contain protein, such as

  • chicken,
  • seafood,
  • turkey,
  • lean pork or beef,
  • tofu, or
  • eggs.

2. Another small section is devoted to grains and/or starchy foods like

  • rice,
  • pasta,
  • potatoes,
  • cooked cereal, or
  • whole-grain bread.

3. A serving of fruit or dairy can occupy the remaining small section.

Carbohydrate Counting and the Glycemic Index Method for Type 2 Diabetes

Carbohydrate Counting

Carbohydrate counting is a meal planning technique based on an allowed maximum carbohydrate count for each meal, and choosing your foods to fit within this limit. The number of carbohydrates a person can consume with each meal and have good control of blood sugar will vary among individuals, depending on the medications taken and activity level.

The Glycemic Index Method for Type 2 Diabetes

The glycemic index (GI) method balances food intake according to the particular glycemic index of the carbohydrate foods you eat. The glycemic index of a food reflects the glycemic response, or conversion to glucose, in the body. The Glycemic index uses a scale of 0 to 100, with higher values corresponding to foods that cause the most rapid rise in blood sugar. Pure glucose, for example, is the reference point and is given a glycemic index of 100. This method of meal planning involves choosing foods that have a low or medium glycemic index instead of foods with a high glycemic index.

Carbohydrates with a high glycemic index that raise blood sugar levels quickly are

  • white bread,
  • bagels,
  • popcorn,
  • russet potatoes, and
  • corn flakes.

Low glycemic index carbohydrates include

  • fruits,
  • sweet potatoes,
  • 100% stone-ground whole wheat bread,
  • pasta, and
  • corn.

Will Exercise Help Control My Diabetes?

Regular physical activity can help control type 2 diabetes and lower blood sugar levels. It also helps with weight control and weight loss. Exercise has other health benefits including

  • decreasing the risk of cardiovascular disease,
  • improving energy level, and
  • helping to manage stress and control mood swings.

You should talk with your diabetes care team to help you determine the appropriate level and extent of physical activity, particularly if you have not been leading an active lifestyle.

What Medications Treat Type 2 Diabetes?

There are many different types of medications for type 2 diabetes treatment. These drugs have different mechanisms of action, with the common goal of reducing and controlling blood sugar levels. In particular, diabetes medications may increase insulin output by the pancreas, increase the sensitivity of cells to insulin, decrease the amount of glucose released from the liver, decrease the absorption of carbohydrates from the intestine, inhibit the absorption of glucose by the kidneys, or slow emptying of the stomach, thereby delaying the absorption of nutrients in the small intestine.

Medications to treat type 2 diabetes are often used in combination and are only one part of a diabetes management program. Healthy eating and regular exercise are other basic components of the ideal diabetes management plan.

Types of medications for type 2 diabetes include:

  • Alpha-glucosidase inhibitors
  • Amylin mimetics
  • Biguanides (metformin [Glucophage])
  • DPP IV inhibitors
  • GLP-1 analogs
  • Insulin
  • Meglitinides
  • SGL T2 inhibitors
  • Sulfonylureas
  • Thiazolidinediones

Each of these groups will be briefly described, along with some common examples of drugs in the particular class. All are taken orally except for certain injectable medications (insulin, amylin mimetics, GLP-1 analogs).

Amylin mimetics, thiazolidinediones, biguanides, and DDP-4 inhibitors

Amylin mimetics, thiazolidinediones

Amylin mimetics include the medication pramlintide (Symlin). This drug is a synthetic analog of human amylin, a hormone synthesized by the pancreas that helps control glucose after meals. Like insulin, amylin is absent or deficient in people with diabetes. Pramlintide is given by injection before meals in people who are taking insulin for type 1 or type 2 diabetes.


Thiazolidinediones work to lower blood sugar levels by increasing the sensitivity of muscle and fat cells to insulin. Drugs of this class tend to improve cholesterol patterns in people with type 2 diabetes. Examples of thiazolidinediones are

An earlier generation of this drug class, troglitazone (Regulin), was discontinued due to its association with liver damage. Rosiglitazone (Avandia) has been associated with an increased risk of heart attack and stroke, and the FDA has imposed restrictions on its use. These drugs should not be used in people with heart failure or liver disease.


Biguanides are a class of drugs that have been used for many years. Metformin (Glucophage) belongs to this class of drugs and works by decreasing glucose production by the liver. Earlier biguanide drugs could have serious side effects, but metformin has been used safely since 1994 for the treatment of type 2 diabetes. Metformin can benefit overweight people in that it often suppresses appetite.

DPP-4 inhibitors

DPP-4 inhibitors are inhibitors of the enzyme dipeptidyl peptidase 4, which breaks down GLP-1 (see below). This means that naturally occurring GLP-1 has a greater effect, leading to decreased stomach emptying and decreased production of glucose by the liver. Examples of DPP-4 inhibitors are

GLP-1 analogs, meglitinides, and alpha-glucosidase inhibitors

GLP-1 analogs

GLP-1 analogs are also known as glucagon-like peptide-1 agonists or incretin mimetics. They work by slowing stomach emptying and slowing the release of glucose from the liver. Examples are

  • exenatide (Byetta),
  • exenatide extended-release (Bydureon),
  • liraglutide (Victoza),
  • dulaglutide (Trulicity),
  • semaglutide (Ozempic), and
  • lixisenatide (Adlyxin).

These are given by injection and are used with other diabetes medications like metformin and sulfonylureas. GLP-1 analogs stimulate the release of insulin from the pancreas. These drugs may promote weight loss and are associated with a low risk of hypoglycemia (low blood sugar).


Meglitinides also act by stimulating insulin release by the pancreas. Unlike sulfonylureas, meglitinides are very short-acting, having peak effects within an hour. They are often taken up to 3 times a day before meals. Examples of meglitinide are

Alpha-glucosidase inhibitors

Alpha-glucosidase inhibitors act by slowing down the digestion of complex carbohydrates, reducing the impact of carbohydrate consumption on blood sugar. Examples of alpha-glucosidase inhibitor drugs are

They are taken with the first bite of food at mealtimes.

Sulfonylureas, SGL2 inhibitors, and insulin


Sulfonylureas are a class of drugs designed to increase insulin output by the pancreas. Older sulfonylurea medications included chlorpropamide (Diabinese) and tolbutamide, which were abandoned due to a higher risk of cardiovascular events in those taking the drugs. Examples of newer sulfonylurea drugs include

One potential risk of these drugs is that they very rapidly lower blood sugar, potentially leading to abnormally low blood sugar (hypoglycemia).

SGL2 inhibitors

SGL2 inhibitors are a relatively new class of medications. These are a class of drugs known as sodium-glucose co-transporter 2 (SGLT2) inhibitors. SGLT2 inhibitors work by blocking the kidneys' reabsorption of glucose. This causes more glucose to be excreted in the urine. Examples of SGL2 inhibitors include

  • canagliflozin (Invokana),
  • empagliflozine (Jardiance), and
  • apagliflozin (Farxiga).

These drugs also may promote weight loss.


Insulin is the hallmark of therapy for type 1 diabetes, but it can also be used for patients with type 2 diabetes. Many different preparations of insulin are available (including rapid-acting and long-acting formulations), with differences in the time required to take effect and the duration of action. Insulin is often considered for the treatment of type 2 diabetes when the condition cannot be controlled by diet, weight loss, exercise, and oral medications.

Can Type 2 Diabetes Be Prevented?

While some risk factors for type 2 diabetes such as genetics and ethnicity cannot be controlled, other risk factors can be minimized with lifestyle modification. For example, it has been shown that in people with prediabetes or people at an increased risk for type 2 diabetes, even modest amounts of weight loss and physical activity can prevent or delay the onset of diabetes. Losing just 5%-7% of total body weight through 30 minutes of physical activity 5 days per week combined with healthier eating showed that it is possible to delay or prevent diabetes. Other studies have shown that reducing the consumption of sugary drinks can delay or prevent type 2 diabetes. Drinking 1-2 cans of sugary drinks per day increased the risk of diabetes by 26% compared with people who did not consume sugared beverages. Eating plenty of fiber and whole grains can help maintain stable blood sugar levels and even reduce the risk of getting diabetes.

For some people at very high risk for developing diabetes (who have prediabetes and other risk factors), medications are recommended to delay the development of type 2 diabetes.

What Is the Prognosis for a Person With Type 2 Diabetes?

Type 2 diabetes can be managed with lifestyle modifications and can require medications. Maintaining good control of blood sugar levels can help prevent or delay many of the known complications of diabetes.

Long-term complications of diabetes include:

  • Cardiovascular disease, including heart attack, stroke, peripheral vascular disease leading to pain in the lower legs (claudication), poor circulation
  • Nerve damage, that often results in pain, numbness, or burning in the extremities (known as diabetic neuropathy)
  • Eye problems, including damage to the retina of the eye due to circulatory problems (diabetic retinopathy), can lead to loss of vision, cataracts, and glaucoma
  • Kidney damage that can lead to kidney failure
  • Erectile dysfunction in men, due to both nerve damage and circulatory problems
  • Skin infections and poor wound healing
  • In addition to optimal control of blood glucose levels and following a diabetes management plan, lowering high blood pressure can help prevent the development of kidney disease and other complications.

Health Solutions From Our Sponsors

Can eating too much sugar cause diabetes?

It's a myth that simply eating too much sugar causes diabetes. Type 1 diabetes is genetic, and it is unknown what triggers the disease, while type 2 diabetes is a combination of genetics and lifestyle.

Where sugar enters the equation is that being overweight is a risk factor for developing type 2 diabetes, and a diet high in calories and sugar can contribute to weight gain.

Reviewed on 9/13/2022
Centers for Disease Control and Prevention. Prediabetes: Your Chance to Prevent Type 2 Diabetes. May 30, 2019.

Harvard University. TH Chan School of Public Health. Soft Drinks and Disease.

Khardori, R. MD. et al. "Type 2 Diabetes Mellitus." Medscape. Sept. 12, 2019.

National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes Diet, Eating, & Physical Activity. December 2016.