Diabetes is a disease in which blood-glucose levels are above normal. People with diabetes have problems converting food to energy. After a meal, food is broken down into a sugar called glucose, which is carried by the blood to cells throughout the body. Cells use the hormone insulin, made in the pancreas, to help them process blood glucose into energy.

People develop type 2 diabetes because the cells in the muscles, liver, and fat do not use insulin properly. Eventually, the pancreas cannot make enough insulin for the body’s needs. As a result, the amount of glucose in the blood increases while the cells are starved of energy. Over the years, high blood-glucose damages nerves and blood vessels, leading to complications such as heart disease, stroke, blindness, kidney disease, nerve problems, gum infections, and amputation.

How Can Type 2 Diabetes Be Prevented?

Although people with diabetes can prevent or delay complications by keeping blood-glucose levels close to normal, preventing or delaying the development of type 2 diabetes in the first place is even better. The results of a major federally funded study, the Diabetes Prevention Program (DPP), show how to do so.

This study of 3,234 people at high risk for diabetes showed that moderate diet and exercise resulting in a 5- to 7-percent weight loss can delay and possibly prevent type 2 diabetes.

Study participants were overweight and had higher than normal levels of blood-glucose, a condition called pre-diabetes (impaired glucose tolerance). Both pre-diabetes and obesity are strong risk factors for type 2 diabetes. Because of the high risk among some minority groups, about half of the DPP participants were African American, American Indian, Asian American, Pacific Islander, or Hispanic American/Latino.

The DPP tested two approaches to preventing diabetes: a healthy eating and exercise program (lifestyle changes), and the diabetes drug metformin. People in the lifestyle modification group exercised about 30 minutes a day 5 days a week (usually by walking) and lowered their intake of fat and calories. Those who took the diabetes drug metformin received standard information on exercise and diet. A third group received only standard information on exercise and diet.

The results showed that people in the lifestyle modification group reduced their risk of getting type 2 diabetes by 58 percent. Average weight loss in the first year of the study was 15 pounds. Lifestyle modification was even more effective in those 60 and older. They reduced their risk by 71 percent. People receiving metformin reduced their risk by 31 percent.

What Are the Signs and Symptoms of Type 2 Diabetes?

Many people have no signs or symptoms. Symptoms can also be so mild that you might not even notice them. Nearly six million people in the United States have type 2 diabetes and do not know it.

Here is what to look for:

The three main kinds of diabetes are type 1, type 2, and gestational diabetes.

Type 1 diabetes, formerly called juvenile diabetes or insulin-dependent diabetes, is usually first diagnosed in children, teenagers, or young adults. In this form of diabetes, the beta cells of the pancreas no longer make insulin because the body's immune system has attacked and destroyed them. Treatment for type 1 diabetes includes taking insulin shots or using an insulin pump, making wise food choices, exercising regularly, taking aspirin daily (for some), and controlling blood pressure and cholesterol.

Type 2 diabetes, formerly called adult-onset or noninsulin-dependent diabetes, is the most common form of diabetes. People can develop type 2 diabetes at any age, even during childhood. This form of diabetes usually begins with insulin resistance, a condition in which fat, muscle, and liver cells do not use insulin properly. At first, the pancreas keeps up with the added demand by producing more insulin. In time, however, it loses the ability to secrete enough insulin in response to meals. Being overweight and inactive increases the chances of developing type 2 diabetes. Treatment includes taking diabetes medicines, making wise food choices, exercising regularly, taking aspirin daily, and controlling blood pressure and cholesterol.

Some women develop gestational diabetes during the late stages of pregnancy. Although this form of diabetes usually goes away after the baby is born, a woman who has had it is more likely to develop type 2 diabetes later in life. Gestational diabetes is caused by the hormones of pregnancy or a shortage of insulin.

Anyone 45 years old or older should consider getting tested for diabetes. If you are 45 or older and overweight (see BMI chart), it is strongly recommended that you get tested. If you are younger than 45, overweight, and have one or more of the risk factors, you should consider testing. Ask your doctor for a fasting blood glucose test or an oral glucose tolerance test.

Even if your blood-glucose level is normal and you have no risk factors, if you are over 45, you may need to remind your doctor to check your blood glucose again in 3 years. If your blood glucose is higher than normal but lower than the diabetes range (what we now call pre-diabetes), have your blood glucose checked in 1 to 2 years. As you get older, your chances of getting type 2 diabetes rise. You are also more likely to get type 2 diabetes if you have one or more of the risk factors.

It means you are at risk for getting type 2 diabetes and heart disease. The good news is if you have pre-diabetes you can reduce the risk of getting diabetes and even return to normal blood-glucose levels. With modest weight loss and moderate physical activity, you can delay or prevent type 2 diabetes.

To find out your risk for type 2 diabetes, check each item that applies to you.

You can do a lot to lower your chances of getting diabetes. Exercising regularly, reducing fat and calorie intake, and losing weight can all help you reduce your risk of developing type 2 diabetes. Lowering blood pressure and cholesterol levels also help you stay healthy.

Then take these steps:

Then take these steps:

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Then take these steps:

Making big changes in your life is hard, especially if you are faced with more than one change. You can make it easier by taking these steps:

Your doctor, a dietitian, or a counselor can help you make a plan. Here are some of the areas you may wish to change to reduce your risk of diabetes.

Your weight affects your health in many ways. Being overweight can keep your body from making and using insulin properly. It can also cause high blood pressure. The DPP showed that losing even a few pounds can help reduce your risk of developing type 2 diabetes because it helps your body use insulin more effectively. In the DPP, people who lost between 5 and 7 percent of their body weight significantly reduced their risk of type 2 diabetes. For example, if you weigh 200 pounds, losing only 10 pounds could make a difference.

Body mass index (BMI) is a measure of body weight relative to height. You can use BMI to see whether you are underweight, normal weight, overweight, or obese. Use the body mass index table to find your BMI.

Be Physically Active Every Day

Regular exercise tackles several risk factors at once. It helps you lose weight, keeps your cholesterol and blood pressure under control, and helps your body use insulin. People in the DPP who were physically active for 30 minutes a day 5 days a week reduced their risk of type 2 diabetes. Many chose brisk walking for exercise.

If you are not very active, you should start slowly, talking with your doctor first about what kinds of exercise would be safe for you. Make a plan to increase your activity level toward the goal of being active for at least 30 minutes a day most days of the week.

Choose activities you enjoy. Here are some ways to work extra activity into your daily routine:

Some people need medication to help control their blood pressure or cholesterol levels. If you do, take your medicines as directed. Ask your doctor whether there are any medicines you can take to prevent type 2 diabetes.