Type 2 diabetes is a chronic condition where your body can’t use insulin effectively, causing blood sugar to rise to harmful levels. It accounts for more than 95% of all diabetes cases worldwide, and the number of people living with diabetes has quadrupled from 200 million in 1990 to 830 million in 2022. As of 2022, 14% of adults globally have diabetes, up from 7% just three decades earlier.
How Type 2 Diabetes Develops
Your body breaks down food into glucose, which enters your bloodstream and serves as fuel for your cells. Insulin, a hormone made by your pancreas, acts like a key that unlocks cells so glucose can get inside. In type 2 diabetes, your cells stop responding to insulin the way they should. This is called insulin resistance. Your pancreas tries to compensate by producing more insulin, but eventually it can’t keep up, and glucose accumulates in your blood instead of reaching your cells.
This process usually develops over years. Many people have elevated blood sugar for a long time before they notice anything wrong. That stage, often called prediabetes, is when blood sugar is above normal but not yet high enough for a diabetes diagnosis. Without changes, prediabetes frequently progresses to full type 2 diabetes.
Who Is at Risk
Some risk factors are within your control, and some aren’t. You’re at higher risk if you:
- Have overweight or obesity
- Are 45 or older
- Have a parent or sibling with type 2 diabetes
- Are physically active fewer than three times a week
- Have had gestational diabetes or gave birth to a baby weighing over 9 pounds
- Have non-alcoholic fatty liver disease
Certain ethnic backgrounds also carry higher risk. African American, Hispanic or Latino, American Indian, Alaska Native, some Pacific Islander, and some Asian American populations are disproportionately affected. Family history is one of the strongest predictors: having even one close relative with type 2 diabetes significantly raises your odds.
Common Symptoms
Type 2 diabetes often develops so gradually that people miss the early signs. The three hallmark symptoms all stem from the same problem: too much glucose in your blood.
Frequent urination happens because your kidneys work overtime to filter out excess glucose, pulling more water along with it. That fluid loss triggers increased thirst as your body tries to replace what it’s losing. And because so much glucose is leaving your body through urine instead of fueling your cells, you may feel unusually hungry even after eating.
Beyond those three, other common signs include extreme fatigue, blurry vision, slow healing of cuts or bruises, unexplained weight loss, and tingling, pain, or numbness in your hands and feet. Some people discover they have diabetes only after a routine blood test, having experienced no obvious symptoms at all.
How It’s Diagnosed
Doctors use one of three main blood tests to diagnose type 2 diabetes. The A1C test measures your average blood sugar over the past two to three months. A result of 6.5% or higher indicates diabetes. Fasting blood sugar, taken after at least eight hours without eating, points to diabetes at 126 mg/dL or above. A glucose tolerance test, where you drink a sugary solution and have your blood drawn two hours later, diagnoses diabetes at 200 mg/dL or higher.
Unless your blood sugar is very clearly elevated with obvious symptoms, a diagnosis typically requires two abnormal results. Those can come from two different tests done at the same time (for example, an A1C and a fasting blood sugar) or the same test repeated on a different day.
Long-Term Complications
Chronically high blood sugar damages blood vessels and nerves throughout your body, which is why type 2 diabetes can affect so many different organs. The eyes are particularly vulnerable: damaged blood vessels in the retina can lead to vision problems and, in severe cases, blindness. The kidneys, which filter your blood around the clock, can gradually lose function. Nerve damage tends to start in the feet and hands, causing numbness or pain that makes it easy to miss small injuries. Foot ulcers that go unnoticed and untreated can become serious infections.
Cardiovascular risk is one of the biggest concerns. People with type 2 diabetes face significantly higher rates of high blood pressure, heart disease, heart attack, and stroke. High blood sugar also creates an environment where infections thrive, increasing susceptibility to urinary tract infections and other complications.
Treatment and Medication
Metformin has long been the standard first medication for type 2 diabetes. It works by reducing the amount of glucose your liver releases into your bloodstream and helping your cells respond better to insulin. For many people, metformin combined with lifestyle changes is enough to bring blood sugar into a healthy range.
When blood sugar control isn’t enough on its own, or when someone has additional health concerns, newer classes of medication play an important role. GLP-1 receptor agonists help your body release insulin more effectively after meals and also promote weight loss. SGLT2 inhibitors work differently: they cause your kidneys to excrete more glucose through urine. Both classes have shown benefits beyond blood sugar control. For people with heart disease or high cardiovascular risk, GLP-1 receptor agonists and SGLT2 inhibitors reduce the chance of major cardiovascular events. SGLT2 inhibitors are also recommended for people with heart failure or chronic kidney disease, where they help protect kidney function and reduce hospitalizations.
Some people eventually need insulin injections if their pancreas can no longer produce enough on its own. Treatment plans are highly individualized, and the approach often shifts over time as the condition changes.
Lifestyle Changes That Matter
Physical activity and diet are not just add-ons to medication. They’re foundational. The CDC’s diabetes prevention program focuses on two core goals: losing 5% to 7% of body weight and building up to regular moderate-intensity physical activity. For someone weighing 200 pounds, that’s a loss of just 10 to 14 pounds, enough to meaningfully improve how your body handles insulin.
Exercise helps in a direct, immediate way: working muscles pull glucose out of your blood even without insulin, and the effect can last for hours after you stop. A healthy diet built around vegetables, whole grains, lean protein, and limited refined carbohydrates helps prevent the sharp blood sugar spikes that make the condition harder to manage.
Can Type 2 Diabetes Be Reversed?
Remission is possible, particularly with significant weight loss. A 2024 systematic review in The Lancet Diabetes & Endocrinology quantified the relationship between weight loss and remission rates one year after intervention. The results were striking: among people who lost less than 10% of their body weight, only about 5% achieved even partial remission. But at 20% to 29% weight loss, roughly half achieved complete remission, meaning their blood sugar returned to fully normal levels without any medication. Among those who lost 30% or more, nearly 80% achieved complete remission.
Remission doesn’t mean the condition is permanently gone. The underlying tendency toward insulin resistance remains, and blood sugar can rise again over time, especially if weight is regained. Still, these numbers show that type 2 diabetes is not necessarily a one-way diagnosis. For people in earlier stages of the disease, substantial weight loss through diet, exercise, or newer weight-loss medications can fundamentally change the trajectory.