What is type 2 diabetes?

Type 2 diabetes is the most common type of diabetes, accounting for about 90 to 95 percent of diabetes cases. In 2017, type 2 diabetes affected around 462 million people worldwide. This condition affects how cells respond to insulin and how well the body regulates blood sugar levels.

Some people may only have mild symptoms, and it may take years before their diabetes symptoms become more severe and noticeable. Type 2 diabetes can usually be prevented or delayed with healthy lifestyle choices, like maintaining a healthy weight and staying active.

Here’s what you need to know about type 2 diabetes, including symptoms, diagnosis, treatment and living with it.

In this article:

What is type 2 diabetes?

Type 2 diabetes is a lifelong condition where the body doesn’t use insulin properly, a state called insulin resistance. Insulin is a hormone released by the pancreas when blood sugar rise. It acts like a key to allow blood sugar into cells in the body to use as energy.

But in type 2 diabetes, the cells don’t respond normally to insulin, so the body can’t regulate blood sugar levels. At first, when cells don’t respond to insulin like they should, the body compensates by making more insulin to keep blood glucose levels under control. As the disease progresses, the body may stop being able to make enough insulin, causing blood glucose levels to stay high and leading to insulin-dependent diabetes.

Type 2 diabetes usually develops slowly. It is commonly found in adults, but it's also happening more frequently in children, adolescents and young adults, with the rise in poor nutrition and obesity in children. People with this condition may not have any noticeable symptoms and can have it for years before being diagnosed.

Type 2 diabetes shares similar symptoms with type 1 diabetes, a less common but unpreventable type of diabetes that happens when the immune system destroys the cells that make insulin.

Causes and risk factors

Type 2 diabetes happens when the body’s cells don’t respond properly to insulin, a hormone the pancreas makes to direct sugar into cells for energy.

When the cells stop responding to insulin like they should, the pancreas tries to make more insulin in an attempt to get the cells to respond to the hormone. However, as the disease worsens, the pancreas stops producing enough insulin, causing the person to start having type 2 diabetes symptoms.

A few factors can contribute to a person’s risk of developing type 2 diabetes.

• Age and ethnicity: Adults (particularly those 45 and above) and people from certain racial and ethnic groups (e.g., African American, Alaska Natives, Hispanic, Latino, or Native American) are more at risk of developing type 2 diabetes.
• Genetic factors: People may be at a higher risk of developing type 2 diabetes if their parent or sibling has it.
• Lifestyle and dietary influences: Unhealthy lifestyle and nutrition choices, such as eating energy-dense foods or foods that are ultra-processed, smoking cigarettes, and being sedentary, can increase a person’s risk of type 2 diabetes.
• Obesity and physical inactivity: People are more likely to develop type 2 diabetes if they suffer from obesity and are physically active less than three times a week.

Symptoms and early signs

It's possible to have diabetes for up to 10 years without showing any symptoms or having only mild symptoms. These symptoms of type 2 diabetes can include the following:

• Blurred vision
• Fatigue and weakness
• Feeling hungry more often than usual
• Frequent infections
• Frequent urination and increased thirst
• Having slow-healing wounds
• Tingling and numbness in the hands or feet

Diagnosing type 2 diabetes

“Because many people with type 2 diabetes may not have symptoms, they may go for years without being diagnosed,” according to Jennie Stanford, MD, dual board certified in family medicine and obesity medicine. “One of the hallmarks of insulin resistance is gaining weight or being unable to lose weight. People should see a health care provider if they are having difficulty maintaining a healthy weight to ensure they don't have insulin resistance,” she recommends.

In addition, regular diabetes screening is recommended in people over 35 years old, especially for people with risk factors, such as belonging to certain racial and ethnic groups, having a family history of diabetes or having specific health conditions like heart disease, high blood pressure, high cholesterol, obesity and polycystic ovary syndrome (PCOS).

Diagnosing type 2 diabetes involves doing blood tests that measure blood sugar levels, including these tests:

• A1C test: Measures the average blood sugar level over the past two or three months.
• Fasting blood sugar test: Measures blood sugar levels after a person has not had food or drink (except water) overnight.
• Glucose tolerance test: Measures how well the body processes sugar by testing blood sugar levels before and after drinking a large amount of glucose.
• Random blood sugar test: Measures blood sugar levels at any time of the day.

Managing type 2 diabetes

Managing type 2 diabetes involves taking treatments and making lifestyle changes that help to lower blood sugar levels, manage high blood pressure and cholesterol levels, reduce the risk of heart disease, and prevent any potential complications.

Blood sugar monitoring

Monitoring blood sugar levels daily or multiple times a day (especially when taking insulin or other diabetes medicines) helps avoid dangerous drops or rises in blood sugar, learn how foods and drinks affect blood sugar, and manage diabetes better. A health care team can adjust meal plans, activity level and medications based on blood sugar results.

Blood sugar levels can be monitored regularly using a blood sugar meter (or glucometer), which measures the sugar in a small drop of blood from the fingertip.

For example, consider products like the CVS Health® advanced glucose meter or the Accu-Chek Guide Me blood glucose monitoring system.

Alternatively, a continuous glucose monitor (CGM) is a wearable device that uses a sensor under the skin to keep track of blood sugar levels throughout the day without needing to do a finger prick each time.

Diet and nutrition guidelines

A healthy diet is an essential part of a diabetes management plan, because it impacts blood pressure, cholesterol levels and a healthy body weight. Different diets work better for different people with diabetes (and potentially other health problems together). It is  recommended to get enough complete protein from beans, eggs, fish and lean meats and to eat high-fiber, low-glycemic index foods.

People with type 2 diabetes should talk to their health care provider before making any big changes to their diet. They may refer patients to a nutritionist or dietitian who can create a personalized meal plan that meets the patient’s health concerns, nutritional needs, personal preferences and weight-management goals.

Exercise and physical activity

Exercise and staying active can help reduce blood pressure, blood sugar and cholesterol levels. Generally, adults with type 2 diabetes should aim for at least 150 minutes of moderately intensity aerobic exercises, like dancing, cycling and running on a weekly basis.

People can also stay active by moving periodically all day. For example, people can take short breaks if they’ve been sitting for a long time and take walks after meals. 

Medications and insulin therapy

A health care provider may recommend diabetes medications like insulin therapy, non-insulin injectable diabetes medications or oral diabetes medications. Insulin is given through injections, pens or pumps, usually several times throughout the day to best control blood sugar levels. They may also prescribe other medicines to help manage blood pressure and cholesterol levels.

People with type 2 diabetes must take medications exactly as prescribed, including when they are feeling well or seeing improvements in their symptoms. Following a prescribed medication schedule helps keep blood sugar levels in check, reduces the risk of needing to go to the hospital and lowers the risk of having serious complications. It’s important to speak with a health care provider if someone with type 2 diabetes has any difficulty sticking with their prescriptions.

Complications of type 2 diabetes

Type 2 diabetes can lead to serious health complications from organ damage when high blood sugar is poorly managed or left untreated. These complications include the following:

• Cardiovascular disease: Type 2 diabetes can affect how well the heart works and can cause problems that contribute to the development of heart diseases, such as coronary disease, heart failure and hypertension.
• Eye damage (retinopathy): Type 2 diabetes can damage blood vessels in the eyes, leading to blurry vision and other serious vision problems like vision loss and blindness.
• Foot problems, infections and poor wound healing: Other severe complications are developing leg and foot problems, such as calluses, numbness, open wounds, pain and sores. Poor wound healing can lead to infections throughout the skin, which may require amputations if infections are deep and severe.
• Gastroparesis: Type 2 diabetes can also damage nerves in the stomach, decreasing the ability of the stomach to empty food into the intestines. This can cause a number of digestive problems, including nausea and vomiting.
• Kidney damage (nephropathy): Type 2 diabetes can damage the blood vessels in the kidneys, causing them to be unable to remove wastes and extra water from the body like they should. People with untreated type 2 diabetes may end up developing kidney disease and eventually kidney failure.
• Nerve damage (neuropathy): Uncontrolled type 2 diabetes can cause nerve damage, leading to symptoms like difficulty walking, muscle weakness, numbness, slow-healing wounds, tingling and intense pain in different areas of the body.

Prevention strategies

Unlike type 1 diabetes, there are ways to help prevent type 2 diabetes. Below are some strategies that may help people lower the risk of developing type 2 diabetes.

Healthy eating habits

Eating healthy foods can help lower the risk of developing diabetes. These include foods rich in fiber, healthy fats, minerals and vitamins, such as fruits, lean proteins, vegetables and whole grains. Limiting foods high in added sugars, salt, saturated fat and trans fats is also a helpful strategy in preventing type 2 diabetes.

Maintaining a healthy weight

If someone is overweight, engaging in physical activity, reducing calorie intake and eating healthy, well-balanced meals can help them achieve and maintain a healthy body weight. Some research suggests losing about 10 percent of a person’s weight if they are overweight can help prevent or delay type 2 diabetes.

Regular medical checkups

Regular checkups can help prevent type 2 diabetes, especially if someone is at an increased risk of developing it. Diabetes screening helps identify high blood sugar levels and enables health care providers to suggest treatments to bring blood sugar levels back to normal.

Regular physical activity

Stay active daily by bicycling, running, taking the stairs and walking. Studies have shown that brisk walking for an hour each day can reduce the risk of diabetes by 34 percent. Even when exercise doesn’t help with weight loss, being active can still help prevent diabetes, improve heart health and boost mental wellness.

Advances in type 2 diabetes research

Although type 2 diabetes doesn't have a cure yet, progress has been made in developing new treatments and medicines. These new treatments not only lower blood sugar but also benefit the heart and kidneys and can sometimes promote weight loss.

Researchers are constantly working to create new drugs to help treat type 2 diabetes, reduce complications, and improve the quality of life for those living with the condition. People with type 2 diabetes can also consider joining available clinical trials to access these newer treatments and contribute to developing new and improved medicines.

Type 2 diabetes is a lifelong health problem that can lead to more serious health issues if left untreated. Eating well-balanced, healthy meals, staying active and getting regular checkups can help lower the risk of developing this condition. If someone has been diagnosed with type 2 diabetes, it’s essential to strictly follow a treatment plan and discuss any concerns they have about medications with a health care provider.

Frequently asked questions

What does type 2 diabetes mean?

Type 2 diabetes is a condition that causes high blood sugar levels because the body isn’t responding properly to insulin and often can’t make enough insulin to regulate blood sugar levels.

What is the difference between diabetes types 1 and 2?

Type 1 diabetes occurs when the body attacks insulin-producing cells in the pancreas, leading to insufficient insulin and high blood sugar levels. It cannot be prevented. Type 2 diabetes happens when the body can’t use insulin effectively. It can often be prevented with exercising, healthy eating and other strategies.

Is type 2 diabetes curable?

No, type 2 diabetes is yet to have a cure, but it can be effectively managed to normal levels by treatments and lifestyle modifications. “People who have type 2 diabetes can often achieve normal blood glucose levels and A1c ranges by adopting the right nutrition strategies, maintaining a healthy weight, exercising regularly and taking the right medications,” explains Dr. Stanford.

This content is for informational purposes only and is not medical advice. Consult your health care provider before taking any vitamins or supplements and prior to beginning or changing any health care practices.