Diabetes, also called diabetes mellitus, is a disease that causes your blood glucose, or blood sugar, levels to be too high. There are three types of diabetes: type 1 diabetes, gestational diabetes, and type 2 diabetes. Type 2 diabetes is the most common type and may be prevented, delayed, or managed by making lifestyle changes.

If you have type 2 diabetes, your body doesn't make enough insulin or doesn't use it well. This is called insulin resistance. Insulin is a hormone that helps glucose get into your cells. Glucose is your cells' main source of energy and comes from the foods you eat. If your body is resistant to insulin, then insulin can't get enough glucose into your cells. This then leads to glucose staying in your blood, leading to high blood glucose levels.

Over time, having too much glucose in your blood can cause health problems. If you are at risk for type 2 diabetes, you might be able to prevent or delay developing it.

Many people are at risk for type 2 diabetes. Your chances of getting it depend on a combination of risk factors such as your genes and lifestyle. The risk factors include:

• Having prediabetes, which means you have blood glucose levels that are high for you, but not high enough to be called diabetes
• Being overweight or having obesity
• Being age 35 or older
• A family history of diabetes
• Being African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander
• Having high blood pressure
• Having a low level of HDL (good) cholesterol or a high level of triglycerides
• A history of diabetes in pregnancy
• Having given birth to a baby weighing 9 pounds or more
• An inactive lifestyle
• A history of heart disease or stroke
• Having depression
• Having polycystic ovary syndrome (PCOS)
• Having acanthosis nigricans, a skin condition in which your skin becomes dark and thick, especially around your neck or armpits
• Smoking

Most of the things that you need to do to prevent or delay getting type 2 diabetes involve having a healthier lifestyle. Lifestyle changes include:

• Lose weight.Weight control is an important part of diabetes prevention. You may be able to prevent or delay diabetes by losing 5 to 7% of your current weight. For example, if you weigh 200 pounds, your goal would be to lose between 10 to 14 pounds. And once you lose the weight, it is important that you don't gain it back.
• Follow a healthy eating plan. It is important to reduce the amount of calories you eat and drink each day, so you can lose weight and keep it off. To do that, your diet should include smaller portions and less fat and sugar. You should also eat a variety of foods from each food group, including plenty of whole grains, fruits, and vegetables. It's also a good idea to limit red meat and avoid processed meats.
• Get regular exercise. Being physically active has many health benefits, including helping you to lose weight and lower your blood glucose levels. These both lower your risk of type 2 diabetes. Try to get at least 30 minutes of physical activity on most days of the week. The amount of exercise you need depends on your age and health. Even small amounts of exercise can be helpful. If you have not been active, talk with your health care provider to figure out which types of exercise are best for you. You can start slowly and work up to your goal.
• Don't smoke. Smoking can contribute to insulin resistance, which can lead to type 2 diabetes. If you already smoke, try to quit.
• Talk to your provider to see whether there is anything else you can do to delay or to prevent type 2 diabetes. If you are at high risk, your provider may suggest that you take one of a few types of diabetes medicines.

If you make these changes, you will get other health benefits as well. You may lower your risk of other diseases, and you will probably feel better and have more energy.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases