Blame it on the obesity epidemic and too much sitting, fast food, and skimping on fruits and veggies: Recent research finds that tens of millions of Americans have undiagnosed Type 2 diabetes or prediabetes. If left untreated, these conditions can damage your organs and put you at risk for heart attack, stroke and limb amputation.

Getting screened —  and learning how to lower your risk — could wind up saving your life.

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Type 2 diabetes

Who's affected: 8.1 million Americans have undiagnosed diabetes, according to the Centers for Disease Control and Prevention. Almost all have Type 2 diabetes (versus Type 1 diabetes, which affects just 5 percent of the population). Type 2 diabetes is a condition that causes your body to produce too little insulin, a hormone that’s critical for allowing organs, cells and fat to absorb blood sugar, their main source of fuel. When glucose has no where to go, it builds up in the blood and causes all kinds of health problems.

The damage: Diabetes can damage your eyes, nerves, kidneys and blood vessels, raising risk for blindness, kidney problems and even amputation. People with diabetes are also at higher risk for heart attacks and strokes, so doctors carefully monitor blood pressure and cholesterol to help lower these risks. 

Get screened: If you’re age 45 or older, ask your doctor about a diabetes screening test. This is usually a fasting blood sugar test or an A1c test, which is a non-fasting check of long-term blood sugar. You may need a screening before age 45, or more frequent checks if you’re at high risk for diabetes if you are: overweight, have high blood pressure, low levels of “good” HDL cholesterol (lower than 35), high triglycerides (over 250) a family history of diabetes, a history of diabetes during pregnancy, or if you’re of African American, Hispanic/Latino, American Indian, Asian American or Pacific Islander descent. You may have diabetes if your A1c test result is 6.5 percent or higher or if your fasting blood sugar is 126 md/dL or higher. Your doctor will probably test you more than once before making the diagnosis.

What to do: If you have Type 2 diabetes, a healthy diet, regular exercise and medication (if needed) can control your blood sugar. Research-proven plus: A diabetes education class and one-on-one meetings with a diabetes educator can help you develop an eating and exercise plan that works for you. Bringing your blood sugar under control with healthy eating, exercise and medication, if needed, can reduce your risk for these life-changing complications.

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Prediabetes

Who’s affected: 86 million Americans have prediabetes, according to the CDC. Yet only 14 percent are aware that their blood sugar is in the diabetes danger zone.

The damage: One in nine people with prediabetes go on to develop Type 2 diabetes each year. But healthy lifestyle changes can slash your risk by 58 percent. In fact, in one major study, losing a small amount of weight, eating a fiber-packed diet and getting 30 minutes of exercise a day worked better than drugs for cutting risk for diabetes in people with prediabetes.

Get screened: The diabetes screening checks outlined above will also determine if you have prediabetes. If your A1c test result is between 5.7 and 6.4 percent or if your fasting blood sugar is between 100 and 125 mg/dL, you could be considered prediabetic. (Your doctor will most likely recheck you before making a diagnosis.)

What to do: Follow the same steps that slashed diabetes risk in the Diabetes Prevention Program: If you’re overweight, aim to lose 5 to 7 percent (or more) of your weight (8 to 11 pounds, for instance, if you weigh 160) by eating more fiber-packed vegetables, fruit and whole grains; cut back on saturated fat (found in whole milk, cheese, ice cream, butter, baked goods and fatty meats) and get 30 minutes of exercise at least five days per week. Research-proven plus: You’ll have a better chance at incorporating these lifestyle changes by signing up for a diabetes prevention class at your local YMCA, church, hospital or community center. To find a program near you, check out the CDC’s diabetes prevention program locater.

Metabolic syndrome

Who’s affected: About 83 million American adults have metabolic syndrome, according to the American Heart Association.The syndrome is diagnosed when people have a handful of risk factors that increase their chances of developing diabetes (and heart disease.)

The damage: Metabolic syndrome raises risk for diabetes five-fold and doubles risk for heart attacks and strokes, note researchers from the University of Texas Southwestern Medical Center at Dallas.

Get screened. You’re at risk of metabolic syndrome if you have any three of these five “metabolic risk factors,” according to the National Institutes of Health:

  • A waist measuring 35 inches or more for women, 40 inches or more for men.
  • High triglycerides. Levels of this blood fat of 150 mg/dL or higher.
  • Low levels of good cholesterol (high-density lipoproteins, or HDL) below 50 mg/dL for women, below 40 md/dL for men.
  • High blood pressure: Blood pressure of 130/85 or higher. (Even if just one of your blood pressure numbers is high).
  • High blood sugar, defined as fasting blood sugar levels above 100 mg/dL.

What to do: Follow a healthy diet, get regular exercise and talk with your doctor about keeping your blood pressure, cholesterol and blood sugar within healthy ranges. Research-proven plus: Follow a Mediterranean-style diet loaded with produce, whole grains, beans and nuts. Most notably, this diet replaces butter with olive oil and red meat with fish and poultry. Nearly 30 percent of people who ate this way reversed metabolic syndrome in a recent Spanish study

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Sari Harrar is an award-winning health, medicine and science journalist whose work appears in Dr. Oz The Good Life magazine, Good Housekeeping, O--Oprah Magazine, Organic Gardening and other publications.