- Type 2 diabetes is caused by insulin resistance that develops over time.
- The main risk factors for type 2 diabetes include being obese, lacking physical activity, aging, having a family history of diabetes, and belonging to certain races or ethnicities.
- To prevent type 2 diabetes, you can lose weight, exercise more, and adjust your diet. Here’s how.
- This article was medically reviewed by Jason R. McKnight, MD, MS, a family medicine physician and assistant clinical professor at Texas A&M School of Medicine.
- Visit the Insider’s Health Reference library for more tips.
Diabetes affects more than 34 million Americans, or about 10% of the American population. There are two types of diabetes, and 90% to 95% of people with diabetes have type 2.
Type 2 diabetes is closely associated with obesity and is more common in people over the age of 45, although anyone can develop it. This is what causes type 2 diabetes, the main risk factors, and how you can prevent it.
What causes type 2 diabetes?
Type 2 diabetes is caused by insulin resistance, which is when the body cannot use insulin properly. Insulin is a hormone produced in the pancreas, a gland located near the stomach. This hormone regulates the process of converting sugar from food into fuel for your body.
When you have insulin resistance, excess blood sugar, in the form of glucose, builds up in your body and deprives you of energy from the food you eat.
“The pancreas can still create insulin, it just doesn’t work as well as it should, which means sugar gets stuck in the blood instead of insulin moving it into the body’s cells for energy,” says Stephanie Redmond, a doctor. pharmacy and co-founder of Diabetes Doctor Supplements.
Insulin resistance develops first in people with prediabetes. A third of Americans have prediabetes and up to 70% of those people will progress to type 2.
Unfortunately, many people with prediabetes don’t know it because they don’t have symptoms, so regular check-ups, including blood tests to check their blood sugar levels, are important.
The Centers for Disease Control and Prevention (CDC) also maintains a risk assessment tool for people concerned about their prediabetes risk.
Risk factor’s
There are many proven factors that can increase your risk of type 2 diabetes:
Obesity
Being overweight or obese greatly increases the risk of type 2 diabetes. In fact, research shows that between 80% and 85% of the risk of developing type 2 diabetes is controlled by obesity.
In general, obese people with a body mass index (BMI) of 30 or more are 80 times more likely to develop type 2 diabetes than people with a BMI of less than 22 (which is within the healthy range).
Sedentary lifestyle
Not getting enough exercise or movement also increases the risk of type 2 diabetes.
For example, a 2016 study of nearly 2,500 people found that every extra hour of sedentary time each day increased the risk of developing type 2 diabetes by 22%.
Conversely, exercising for 30 minutes a day can reduce the risk of developing diabetes by as much as 58% when combined with dietary changes. This is because during exercise your muscles use more blood sugar for fuel, lowering your blood sugar levels.
Years
Diabetes is more common in people over the age of 45. In fact, about 25% of Americans over the age of 65 have diabetes, and almost all of that number has type 2.
This is because insulin resistance increases with age, at the same time that the pancreas begins to lose function, which can contribute to the development of type 2 diabetes.
Genetics
Although type 2 diabetes is largely caused by obesity and a sedentary lifestyle, genetics is also a major risk factor. For example, having a parent with type 2 diabetes increases the risk of the disease 2 to 4 times.
“My favorite saying about type 2 diabetes is that genetics loaded the gun and lifestyle pulls the trigger,” says Redmond.
Read more about whether type 2 diabetes is genetic and what to do if it runs in your family.
Race and ethnicity
Non-white Americans are more likely to develop type 2 diabetes. According to the American Diabetes Association, type 2 diabetes occurs in:
- 7.5% of non-Hispanic white Americans
- 9.2% of Asian Americans
- 11.7% of non-Hispanic blacks
- 12.5% of Hispanics
- 14.7% of American Indians
A 2018 study looking at diabetes rates in African Americans found that biological differences, including a body type that was more likely to have fat around the abdomen, explained most of the increased risk. But there are also socioeconomic risk factors: Minorities may have less access to affordable health care or quality food options.
“Why these groups are at higher risk is a complex question without a simple answer. For the most part, it is related to environmental and genetic factors,” says the Food and Drug Administration (FDA).
How to prevent type 2 diabetes
Even if you have risk factors for type 2 diabetes, you can prevent the disease and reverse it during the initial stages of insulin resistance and prediabetes. In fact, researchers estimate that 90% of cases of type 2 diabetes in the U.S. can be prevented.
“The key is to act early to prevent the pancreas from wearing out and getting damaged,” says Redmond.
For example, people who participate in CDC-supported lifestyle change programs, including exercise and weight loss, can reduce their risk of type 2 diabetes by 58%. For people over 60, the risk falls by 70%.
Here is what you can do to prevent type 2 diabetes if you are at risk:
- Lose weight. Dropping 7% to 10% of your body weight can reduce your risk of developing type 2 diabetes by 50%. Follow our guide on how to lose weight and talk to your doctor about what’s right for you.
- Exercise. Even moderate exercise, like brisk walking for 30 minutes every day, can reduce your risk of developing type 2 diabetes by 30%.
- Stop smoking. Cigarette smokers are twice as likely to develop type 2 diabetes.
- Avoid drinking excessively. Excessive alcohol consumption can increase the risk of type 2 diabetes, although moderate alcohol consumption can reduce the risk by improving the effectiveness of insulin.
- Adjust your diet. Eating whole foods and avoiding sugary and processed snacks can help regulate your blood sugar levels.
Preventive care and regular physical exams are also important, as most people find they have high blood sugar levels during routine blood tests.
“This is why regular annual screenings are so important, to make sure that if you don’t have symptoms we can still detect a higher than normal blood sugar level and take action early,” says Redmond.
