If you’re over age 45 and you get regular checkups, your doctor will probably test you for diabetes. But only about half of doctors, according to recent research, raise the alarm when those same tests indicate prediabetes, characterized by slightly elevated blood sugar that hasn’t yet progressed to full-blown clinical diabetes.

Why that’s a dangerous omission…

Prediabetes now affects 38% of American adults. The risk increases substantially over age 60.

Unless you treat prediabetes as a wake-up call to change your lifestyle, your chance of progressing to clinical diabetes is a whopping 70%.

Prediabetes hurts your health now—even if it doesn’t progress to clinical diabetes. Years of higher-than-normal blood sugar can cause some of the same damage as full-fledged diabetes.

It’s much easier to reverse prediabetes than full-blown diabetes. In prediabetes, your body is developing insulin resistance so that you need more insulin to regulate blood sugar. But if producing that extra insulin overtaxes your pancreas so that you can’t keep up with the demand for insulin, you’ve got type 2 diabetes—and reversal is much harder to achieve.

America’s doctors are missing the boat on treatment of prediabetes, too. Even when patients are diagnosed with prediabetes, only 33% get counseling about nutrition…only 32% get counseling about exercise…and a mere 26% about both.

My advice: As a patient, you need to take prediabetes seriously. Here’s how…


Prediabetes is a stage between a normal blood glucose level and one that’s so high that it triggers the “big” diagnosis. It’s measured with the same blood tests that doctors use to identify diabetes. My advice: Given the enormous number of people who develop prediabetes, every adult should get tested—without exception.

There are three common tests—any one of which is sufficient to diagnose prediabetes, so you’ll need only one…

Fasting plasma glucose (FPG). This is the standard blood test for diagnosing both diabetes and prediabetes. Take the test first thing in the morning (since you have to fast for at least eight hours). A reading of less than 100 milligrams per deciliter (mg/dL) is normal…100 mg/dL to 125 mg/dL is prediabetes…and 126 mg/dL or higher means you already have diabetes.

A1C (glycated hemoglobin). This blood test measures the percentage of glucose that’s attached to the hemoglobin in blood. It indicates your average blood sugar level over the last two or three months. I recommend this test because it’s fast, inexpensive and doesn’t require fasting. A normal reading is below 5.7%. A reading between 5.7% and 6.4% indicates prediabetes. A reading of 6.5% or higher means diabetes.

Glucose tolerance test. This test is more cumbersome but more accurate. Instead of eating a meal, you consume a standard amount of glucose, and then your blood glucose is measured at 30 minutes and at least one hour and two hours afterward. If your blood sugar tests high (between 140 mg/dL and 199 mg/dL) two hours after drinking the glucose solution, it means that you have prediabetes. If your blood sugar tests 200 mg/dL or higher, then you have diabetes.

How often should you get tested? If your result is normal but you also have two or more diabetes risk factors (such as being overweight and sedentary), get tested annually…otherwise, every three years is fine. But if the test shows prediabetes, you should embark on a program to reverse it—and make sure your doctor retests you more frequently, such as every six months, to see if your changes are working.


Most people with slightly high blood sugar can lower it with basic lifestyle changes, along with medication in some cases. Make sure you discuss various interventions with your physician, and, if possible, work with a diabetes educator, especially one associated with a diabetes program. The basics…

Start with weight loss. Not everyone with prediabetes is overweight—but most patients are. Often, losing just 10 pounds is enough to improve insulin sensitivity and bring blood sugar into the healthy range.

Take a daily walk. A daily 30-minute walk reduces your risk of developing diabetes by 30%, according to the Harvard School of Public Health’s Nurses’ Health Study and the Health Professionals Follow-Up Study. Exercise increases insulin sensitivity. It also increases metabolism and muscle mass, which lower glucose even more.

Eat whole grains. Research has shown that people who eat two to three servings of whole grains daily, compared with those who eat little or none, are 30% less likely to develop type 2 diabetes. Processed grains—such as white rice and most breakfast cereals, etc.—are digested quickly and cause a faster rise in glucose.

Minimize red meat. Red meat (especially fatty cuts) is high in saturated fat, which can increase diabetes risk. Be especially sparing with processed red meats, such as bacon and bologna. In one large Harvard study, people who ate as little as two ounces of processed red meat daily had a 19% increased risk of developing diabetes.

Say no to sugary soft drinks. A Harvard study found that women who drank one or more of these beverages a day, compared with those who drank them rarely, had an 83% higher risk of developing diabetes. Beware of any sugar-sweetened drink, including sugar-sweetened teas and sports drinks. My advice: Sugary drinks should be avoided altogether.


Nearly 10 years ago, the American Diabetes Association updated its guidelines to include metformin (Glucophage) for treating high-risk patients with prediabetes. Research shows that it cuts the risk of developing diabetes by 31%. Yet it’s still prescribed for only a small fraction of these patients. The drug can cause diarrhea and gas, but the side effects usually go away within a week or two. It can also diminish appetite, which is sometimes a benefit for people trying to lose weight. I recommend it for people who can’t get their blood sugar under control with lifestyle measures alone. If you tolerate it well, you can stay on it indefinitely.

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