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What Is Type 2 Diabetes?

Causes, Symptoms, Diagnosis, and Treatments

Never mind the second-place name—more than 90 percent of people with diabetes have Type 2. And a substantial number don’t even know they have it. So, what are its giveaway symptoms? How do you avoid complications? Will the right diet help you reverse it? We’re here to empower you with clear answers to all your pressing Qs.

In This Article: 
Definition Causes | Symptoms | Diagnosis | Treatments | Complications Fast Facts | Risk Factors | Frequently Asked Questions | Support 

Featured Voices: 
Elena Christofides MDCaroline Apovian MD, and Sharon Bergquist MD

What is type 2 diabetes?

Type 2 diabetes occurs when your blood sugar levels become elevated and you develop insulin resistance. During insulin resistance, your body is no longer able to effectively respond to insulin, making it unable to fully absorb and use the sugar from the from the food you eat for energy. As a result, that sugar then stays in your blood, and can eventually bring about a chronic condition that can lead to serious health issues if it is not treated and managed. However, when type 2 diabetes is caught and addressed early, this process is completely reversible, and many of the symptoms and complications can be avoided.

Type 2 Diabetes Fast FactsInfographic by Lauren Hunter

What causes type 2 diabetes?

There are two key players involved. Your pancreas produces insulin in response to food ingestion and elevated blood sugar levels. Insulin is the hormone that facilitates your body’s absorption and use of carbohydrates, which it breaks down into sugar. When you have type 2 diabetes, your insulin response no longer functions as it should. This causes the following to happen:

  1. Your muscles, liver, and fat (also known as peripheral tissues) become insulin resistant, which means they no longer respond to insulin and are unable absorb and use glucose.
  2. The beta cells in your pancreas become exhausted and can no longer produce sufficient insulin.

Can obesity cause type 2 diabetes?

How we understand obesity and type 2 diabetes matters as they are the most widespread metabolic disorders. Though they’re separate conditions, they often overlap.

Weight and nutrition specialist Caroline Apovian MD explains, “Although lifestyle is very important for both obesity treatment and diabetes, there are people who never develop obesity, and there are people who do have obesity for whom lifestyle changes don’t always work, because obesity is a disease and the body defends a higher body weight set point. Even after weight loss, the hormonal changes involved in obesity can force a patient to regain the weight.”

“Type 2 diabetes patients did not bring it on themselves,” emphasizes diabetes and metabolism expert Elena Christofides MD. “This is not a moral failing.”

But both the prevalence of obesity and type 2 diabetes is increasing. Why? Researchers believe it’s our environment. There has been an increased availability of high-fat, high-sugar, highly processed foods. These foods often contain other “non-food items.”

Some of these ingredients have been found to act as endocrine disrupters and change the way our bodies store fat and process energy. While there have not been sufficient studies to prove a causal relationship, most doctors and nutritionists recommend avoiding them.

What are the signs and symptoms of type 2 diabetes?

  • Polydipsia is an excessive thirst that’s stronger than that feeling you get on a hot day. If water doesn’t quench it, and your mouth feels cottony and dry more often than not, you may be experiencing polydipsia.
  • Hyperphagia is an unceasing hunger that is more bottomless than the hangry feeling you get after skipping meals. If you’ve eaten a full and balanced meal (think a dinner-sized plate) and keep going back for more, without satisfaction, it could be hyperphagia.
  • Polyuria is the urge to urinate more often than usual. The number of bathroom trips varies depending on your lifestyle, what medications you’re taking, and how much you drink, but urinating more than 7 or 8 times a day can be a sign of type 2 diabetes.
  • Weight loss can affect some people with type 2 diabetes and could be a warning sign if you’ve not changed your diet or exercise routine.
  • Blurred vision can come on quite suddenly and may also come and go because it is a result of high blood sugar levels that cause the lens of your eye to swell.
  • Headaches are often moderate to severe and may occur frequently.
  • Yeast infections may happen because yeast feeds off of sugar, which is why increased blood glucose levels could up your risk for yeast infections.
  • Extremity paresthesia or tingling feet and hands may feel similar to the sensation you get when your foot “falls asleep” and could indicate damage to your small blood vessels, an early sign of diabetic neuropathy.
  • Dry mouth is that cottony feeing, often accompanied by excessive thirst.
  • Fatigue is more than just feeling tired. If you feel like you are never rested, your body feels heavy, and small tasks seem overwhelming, you may be experiencing fatigue. Walking from the bedroom to the kitchen may start to feel like an Olympic sprint.
  • Sore, tender gums can make brushing with even the softest toothbrush feel painful.

Signs and symptoms of Type 2 diabetesIf you have one or more of these symptoms contact your doctor.

How is type 2 diabetes diagnosed?

A hemoglobin A1C (Hgba1c) test measures your average blood sugar levels and is typically used to diagnose and monitor type 2 diabetes. It is the average of 3 separate fasting blood glucose tests taken monthly for 3 months. The result is given in percentages. A diagnosis of type 2 diabetes means you have increased blood sugar levels, typically indicated by a hemoglobin A1C of 6.5% or higher. A1C levels between 5.7 and 6.4% can indicate prediabetes.

What is prediabetes?

Before you’re diagnosed with type 2 diabetes, you become pre-diabetic, meaning that your blood sugar levels are elevated, but not elevated enough for a type 2 diagnosis. The most important thing to know about prediabetes is that it’s easier to reverse than type 2.

Think of a diagnosis of prediabetes as an opportunity to prevent the progression to type 2, and a good reason to keep up with regular checkups and physicals to make sure your doctor doesn’t miss this early phase and only find out about your full-blown diabetes later when you start having symptoms.

What are key differences between type 1 diabetes and type 2 diabetes?

When comparing type 1 vs type 2 diabetes, there are a few major differences:

  • Type 1 diabetes is an autoimmune condition. You can’t reverse type 1 diabetes, you can only manage it. Type 2 diabetes can be reversed with effective intervention and lifestyle changes.
  • In type 1 diabetes, your pancreas is unable to produce insulin, whereas in type 2 diabetes, your insulin production is limited, and the response of your body to that insulin is decreased.
  • A person with type 1 diabetes could die without their insulin medication. A person with type 2 diabetes should avoid treatment with insulin, unless their pancreas is completely failing.

How does type 2 diabetes relate to insulin resistance?

Insulin resistance causes type 2 diabetes, but a person can have insulin resistance without having type 2 diabetes. “Diabetes is about energy in and energy out,” explains Dr. Chistofides. “In the case of type 2 diabetes, there is a mismanagement between how the body matches energy intake and energy demand.” Insulin insensitivity is the symptom of this energy mismanagement that can lead to insulin resistance.

If you have a diet high in processed foods with added sugar, initially your body will keep releasing insulin as it tries to absorb and use glucose. If you have prediabetes and don’t limit your over-consumption of sugary foods, here’s what can happen:

  1. Over time, the excessive release of insulin overwhelms your peripheral tissues, and they become less responsive to it, resulting in insulin insensitivity.
  2. At this point, your body is no longer properly absorbing and using glucose, so your blood sugar levels remain elevated.
  3. The beta cells in your pancreas continue to produce and release insulin as they try to manage your blood sugar levels.
  4. Your beta cells become damaged and die, and your body can no longer produce sufficient levels of insulin, leading to hyperglycemia (high blood sugar).
  5. Hyperglycemia, represented by elevated hemoglobin A1C levels, is the last symptom of energy mismanagement, and leads to a diagnosis of type 2 diabetes.

Who gets type 2 diabetes?

“There are people who are healthy and get type 2 diabetes and there are people who are unhealthy and get type 2 diabetes,” says Dr. Christofides. “It’s a bit like lung cancer in that not everyone who smokes gets lung cancer, and some people get lung cancer who have never smoked.”

“Type 2 diabetes is multifactorial,” explains Sharon Bergquist MD, “meaning that a person’s genes, environment, and lifestyle work together to lead to the disease. Some of the increased risk may be attributed to genetic susceptibility, but a higher percentage is likely due to environment and lifestyle, which can be influenced by culture and socioeconomics.”

Are some people more likely to develop type 2 diabetes than others? ­

“A person who has a highly inflammatory diet and carries excess adiposity around their central organs is more likely to get type 2 diabetes,” says Dr. Christofides. Excess weight and obesity are risk factors for type 2 diabetes, but how your body stores and manages weight can also be an early indicator of risk.

Research has shown that people who carry too much fat around their middle are more prone to health risks such as type 2 diabetes. Certain communities also show a greater propensity for developing type 2 diabetes, including people who are Black, Latinx, Asian, and Indigenous.

Factors that can put you at an increased risk for developing type 2 diabetes include:

  • Genetic predisposition
  • Family history of diabetes and cardiovascular disease
  • Obesity
  • Sedentary habits
  • Decreased levels of HDL (good cholesterol)
  • High blood pressure (hypertension)
  • A diet high in processed foods and added sugars
  • History of heart disease or stroke
  • Depression
  • Polycystic ovary syndrome (PCOS)
  • Elevated triglyceride levels in your blood
  • Higher waist to hip ratio
  • Systemic inflammation

How can I manage my type 2 diabetes?

Nobody likes dieting, but according to Dr. Apovian, “Weight losses of as little as 3-5% have been shown to reduce risk of type 2 diabetes in people who have been medically advised to lose weight. Dietary changes are not only to reduce calories but to change macronutrient content and quality, meaning more fiber, more protein, less simple carbohydrates, healthier fats, and reducing processed foods.”

When doctors and nutritionists refer to inflammatory diets, they’re largely talking about processed foods. But it’s not just food that can be inflammatory. Certain lifestyle factors can also set your body up for systemic inflammation which can then decrease your ability to manage glucose.

Factors that promote systemic inflammation include:

  • Processed foods
  • Added sugars
  • Excessive alcohol intake
  • Inadequate sleep quality and quantity
  • Certain autoimmune conditions
  • Smoking
  • Anxiety and depression

Managing type 2 diabetes is an individual practice, but you can apply some general recommendations:

  • If your doctor advices weight loss for medical reasons, losing weight can improve insulin sensitivity and decrease blood glucose levels.
  • There is no one best diet, but the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet have been found effective in managing both diabetes and cardiovascular risk.
  • Exercise. If you’re new to exercise, begin with moderate movement, and increase volume and intensity as your body adapts. The best exercise for controlling type 2 diabetes is a combination of cardio and strength training.
  • Avoid processed foods. Eat as little from packages as possible. Shop along the perimeter of the grocery store, where you’ll typically find the most nourishing food.
  • Do your best to get enough sleep
  • If medication is required, work with your doctor to find the prescription that works best for you.

What are treatments for type 2 diabetes?

Unless it’s absolutely necessary, insulin should not be used to treat type 2 diabetes. Dr. Bergquist explains, “Injecting insulin improves blood sugar but worsens underlying insulin resistance. Insulin is a fat-storage hormone. Higher insulin leads to more fat storage in organs where it’s toxic, making them more insulin resistant.”

“Insulin should only be used when the pancreas fails and the B cells cannot be regenerated,” says Dr. Apovian. “When type 2 diabetes is caught early enough, you can reverse it with lifestyle, medication, and bariatric surgery.” In certain cases, when a person is severely overweight, bariatric surgery is a successful treatment for type 2 diabetes, because it effectively decreases a person’s body weight set point and can reverse hormonal imbalances that underlie obesity and fuel type 2 diabetes.

Additionally, new type 2 diabetes medications have been approved by the FDA, including a class of drugs known as glucagon-like-peptides (GLP-1), which aid the pancreas in producing more insulin by decreasing glucose production in the liver. Researchers are also working to understand the role that inflammation and hormonal imbalances have in the development of T2D.

Can type 2 diabetes be reversed?

Yes! The good news is that several studies have shown that type 2 diabetes can be reversed. You are considered in remission from type 2 diabetes when you have had normal blood sugar levels for a year without medication.

One of the most important components in reversing type 2 diabetes is early detection. Dr. Bergquist explains, “The pancreas produces insulin. The longer you have diabetes, the more damage your insulin resistance causes to your pancreas, and the less likely your pancreas is to recover. Hence, the possibility for remission decreases the longer you have diabetes. But there’s a wide window during which you can be successful.”

How long can you live with type 2 diabetes?

Type 2 diabetes doesn’t have to be a chronic condition. To the contrary, a type 2 diabetes diagnosis is the moment to begin changing habits and working towards a healthier and longer life. “What you do every day can make a difference,” says Dr. Christofides. “Park at the far-end of the lot. Try taking the stairs. Consider buying only fresh foods and avoiding things in packages.”

There is no one best type 2 diabetes diet. Focus on fresh, and focus on balance. Include vegetables, lean proteins (meat or plant sources), whole grains, nuts, seeds, legumes, and whole fruits.

Get moving. Exercise is one of the most important things you can do for overall health, including mental well-being. Fitness is also one of the best ways to keep weight off once you’ve lost it.

Find activities you enjoy and try sharing those with friends and family. Exercise doesn’t have to happen in the gym. Grab a friend and go for a fast walk through the neighborhood or take a hike in the park. The vitamin D will give you an extra boost of health and well-being.

Where can I find help and support for managing my type 2 diabetes?

Diabetes Educators. The American Diabetes Association has a diabetes education finder, where you can find diabetes counseling in your zip code. You may also want to work with a diabetes dietitian to clarify questions about carbs, eating schedules, and more. A diabetes dietitian falls under the umbrella of medical nutrition therapy and is covered by Medicare and many insurance policies. Exercise is another crucial part of care, and you may be eligible for physical therapy as part of your diabetes medical management plan. You can find more information on state-by-state coverage here.

Type 2 diabetes isn’t a solo condition. It’s largely influenced by our culture and community health practices. Expanding your community to a healthy support system can also be an important part of managing your type 2 diabetes.

Family and friends. Get them on board by creating new food habits together. Often, we feel pressure to maintain the status quo for our families while adjusting our own diets. The changes you’re making to improve your health will also improve the health of your family. Choose healthful meals that you can all enjoy together and try to resist making separate meals for yourself.

Support groups (online or in person) can be a way to share your experiences and knowledge with people who are going through the same challenges and changes. You can choose an in-person support group, an online one, or both. Visit the American Diabetes Association to find in-person support groups near you, or check out The Defeat Diabetes Organization. A few reputable online support groups are:

What are the health risks associated with type 2 diabetes?

Type 2 comes with real health risks, and these risks may advance with the duration and severity of your condition. Here are 3 warning signs to look out for:

Insulin resistance that accompanies type 2 diabetes can lead to other serious medical conditions such as:

  • High cholesterol
  • High blood pressure
  • Heart attack
  • Stroke
  • Cardiovascular disease

If you have type 2 diabetes, you should also be extra mindful of your heart and circulation. As Dr. Christofides explains, “The risk of dying from cardiovascular disease is only related to the underlying insulin insensitivity. This has nothing to do with your A1C levels and is not alleviated by lowering blood sugar.”

But type 2 diabetes pathophysiology does not have to be a death sentence. The risk of cardiovascular disease and mortality can be lowered by decreasing insulin insensitivity, largely through diet and lifestyle changes. Exercise may be particularly important because activities like resistance training and aerobic activity can increase insulin sensitivity.

Hyperglycemia (high blood sugar levels) can cause myriad problems, with the primary complications being:

Lowering your A1C is a crucial step in preventing these conditions. A newer class of drugs, GLP-1s, are very effective at lowering blood sugar levels, while helping to improve liver and heart health. Managing your type 2 diabetes is the best way to prevent complications related to hyperglycemia.

Hypoglycemia (low blood sugar) can be a risk-factor with certain medications used to help keep your blood sugar from getting too high. Additional factors that can promote hypoglycemia are missing meals and alcohol. Low blood sugar stimulates the release of adrenaline, also known as epinephrine, which causes symptoms like:

  • Feeling shaky
  • Nausea
  • Sweating
  • Chills
  • Anxiety
  • Rapid heartbeat
  • Confusion
  • Feeling lethargic
  • Headaches
  • Tingling or numbness in your lips, tongue, or cheeks

Typically, blood sugar levels below 70 mg/dL signify hypoglycemia. The American Association for Diabetes recommends treating hypoglycemia with the 15-15 rule:

  • Consume 15 grams of carbohydrates to raise your blood sugar levels.
  • Wait 15 minutes.
  • Check your blood sugar levels again. If your blood sugar levels are still below 70 mg/dL, have another 15-gram serving of carbohydrates.
  • Repeat these steps until your blood sugar is above 70 mg/dL.
  • Once your blood sugar is above 70 mg/dL, eat a light meal or snack to maintain it.

When your blood sugar plummets, it can be tempting to eat as much as possible until you feel better. Try your best to avoid this, as it can then cause it to sky-rocket, making you feel worse.

When low blood sugar isn’t treated and you need intervention, it’s considered an emergency event. In this case, glucagon is often used. Glucagon is a hormone produced by your pancreas that stimulates the liver to release glucose into your bloodstream. Injectable glucagon is used to treat hypoglycemia when the 15-15 rule is ineffective.

If you experience episodes of hypoglycemia, discuss a treatment plan with your doctor. Glucagon kits are available by prescription, and your doctor may recommend keeping one. It’s important that you and the people in your support system know how to recognize signs of hypoglycemia, understand the 15-15 rule, and are able to administer glucagon.

FAQ: Frequently Asked Questions

Is type 2 diabetes genetic?

Over 75% of kids with type 2 diabetes also have a relative with the condition. But this could be due to similar lifestyles in the family rather than genetic factors. Like any condition, some people have a genetic predisposition towards both insulin insensitivity and type 2 diabetes, but the primary factor governing type 2 diabetes is lifestyle.

How often do I need to monitor my blood sugar if I have type 2 diabetes?

You and your healthcare provider should decide when and how often you need to check your blood sugar. You can keep a record in a smart phone app or on paper so you can easily chart your variations. Doctors recommend that diabetes patients get an A1C test at least two times a year.

How has type 2 diabetes changed over time?

Type 2 diabetes used to be called adult-onset diabetes or non-insulin dependent diabetes because it was diagnosed mainly in adults who did not require insulin to manage their condition. However, because more children are starting to be diagnosed with T2D, and insulin is used more frequently to help manage type 2 diabetes, referring to the condition as “adult-onset” or “non-insulin dependent” is no longer accurate or used.

Can type 2 diabetes be cured?

Yes! Your greatest opportunity to reverse type 2 diabetes is early detection and intervention.

Type 2 Diabetes Fast Facts

  • 90-95% of people with diabetes have type 2
  • More than 1 in every 10 adults has diabetes
  • Over 25% of adults over 65 have diabetes
  • Exercise and weight loss reduce the risk of prediabetes becoming type 2 diabetes by 58%
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