Prediabetes, the leading risk factor for type 2 diabetes, is a wake-up call. The condition, which afflicts approximately 84 million American adults, is a sign that something is metabolically awry. Unfortunately, only about 12% of people with prediabetes are aware that they have this problem. Although it sounds scary to have a metabolic disorder, there is so much you can do to prevent it from getting worse. In fact, many people who improve their lifestyle habits (some take medicine, too) are able to do more than prevent type 2 diabetes; some are even able to reverse prediabetes. Without changes, however, 37% of individuals with prediabetes are likely to progress to full-blown type 2 diabetes within 4 years, and most will have the diagnosis within 10 years. Many will develop heart disease as well, even if they don’t move on to diabetes. Even some types of cancers are linked to prediabetes and type 2 diabetes. Because we don’t really feel prediabetes and there are often no symptoms, it’s easy to ignore it and to put off making changes. Don’t be tempted by that. You’ll see why in the next sections. Keep reminding yourself that this is an opportunity to reverse the course. There’s really quite a lot to celebrate!
Diagnosing Prediabetes and Diabetes
You have prediabetes if your blood glucose level is higher than normal, but below the level of diabetes. The chart below shows you the tests and results that health care providers use to diagnose diabetes and prediabetes. If you have an abnormal result, your health care provider will order a second test to confirm your diagnosis.
Blood Glucose Levels to Diagnose Prediabetes and Diabetes
What Is Borderline Diabetes?
To some people, borderline diabetes means prediabetes. To others, it means type 2 diabetes that is managed without medications. Because of the confusion, it is best to avoid using the term “borderline diabetes.” If someone tells you that you have borderline diabetes, ask for clarification.
Prediabetes and Diabetes Glossary
Here are a few bits of medical jargon that you may hear when you visit your health care provider or see on your office paperwork.
A1C
A1C, also called hemoglobin A1C, is an indicator of your average blood glucose level over the past 3 months. A1C is a measure of the amount of hemoglobin within your blood cells that is coated with glucose. Hemoglobin is a protein that travels with your blood cells to provide oxygen to your tissues. If you have high levels of glucose in your blood, more glucose will stick to the hemoglobin molecule, and your A1C will be elevated. An A1C measurement between 5.7% and 6.4% is suggestive of prediabetes. If a second measurement falls within the same range, you meet the criteria for the diagnosis of prediabetes.
Impaired fasting glucose (IFG)
When your fasting blood glucose falls between 100 and 125 mg/dL, you have impaired fasting glucose. If this level is confirmed on a repeat test, you meet the criteria for the diagnosis of prediabetes.
Impaired glucose tolerance (IGT)
When the result of your 2-hour oral glucose tolerance test (OGTT) falls between 140 and 199 mg/dL, it indicates that you have impaired glucose tolerance. If this level is confirmed on a repeat test, you meet the criteria for the diagnosis of prediabetes.
Some people with prediabetes will have impaired fasting glucose. Others will have impaired glucose tolerance, and some will have both. A1C levels are affected by either or both IFG and IGT. Any two measurements (A1C, IFG, and/or IGT) can be used to diagnose prediabetes.
Type 1 diabetes
Type 1 diabetes is an autoimmune disease and affects 5–10% of Americans with diabetes. In type 1 diabetes, the pancreas is damaged because of the autoimmune dysfunction, and it makes very little insulin or no insulin at all. People with type 1 diabetes require insulin by injection or an insulin pump. Although type 1 diabetes is typically diagnosed in children and young adults, it can be diagnosed well into adulthood. Prediabetes is a risk factor for type 2 diabetes. This book is a guide to help prevent or delay type 2 diabetes only.
Blood Sugar versus Blood Glucose
“Blood sugar” and “blood glucose” mean exactly the same thing. “Blood glucose” is used throughout this book, but “blood sugar” is also commonly used in diabetes practices. Both terms refer to the concentration of glucose in the bloodstream. In the U.S., we use the unit mg/dL (milligrams glucose per deciliter of blood) to report blood glucose levels. In other parts of the world, blood glucose is reported in mmol/L (millimoles of glucose per liter of blood).
Risk Factors for Prediabetes and Type 2 Diabetes
Having prediabetes is a strong risk factor for developing type 2 diabetes. Each of the other following factors increases your risk for both prediabetes and type 2 diabetes.
Risk factors beyond your control
• Age: With each birthday, your risk grows. Health care providers usually start screening their healthy patients at age 45 years.
• Sex: Men have a greater risk than women.
• Race/ethnicity: Your risk is higher than average if you are African American, Latino, Native American, Asian American, or Pacific Islander.
• Family history: If individuals in your immediate family have prediabetes or type 2 diabetes, your risk is increased.
• Gestational diabetes: If you are a woman who previously had gestational diabetes (diabetes that occurred during pregnancy), your risk is higher.
• Polycystic ovary syndrome: If you are a woman with polycystic ovary syndrome, you have a higher chance of having prediabetes.
Take Control of These Risk Factors
Here is where you can influence your risk for developing type 2 diabetes and even reverse prediabetes. These risk factors are discussed in greater detail in later chapters. Some are directly related to the development of prediabetes and type 2 diabetes. Others may simply be signals that your risk is higher than average.
• Overweight and obesity: As weight increases, so does your risk.
• Inactivity: Being physically active helps your body use glucose better.
• High blood pressure
• High triglyceride levels
• Low HDL (good) cholesterol levels
• Heart disease or blood vessel problems
• Sleep deprivation: Too little sleep can make your body more resistant to the effects of insulin. Getting between 7 and 8 hours of sleep most nights is associated with the lowest risk of developing type 2 diabetes.
• Smoking
You can get an estimate of your risk for developing type 2 diabetes, heart disease, and stroke within the next 8 years. Simply visit the American Diabetes Association website (diabetes.org) to take the online health assessment. Click on “Are You at Risk?” on the homepage and then “My Health Advisor.” This assessment is free and powerful.
Are Obesity, Prediabetes, and Type 2 Diabetes Lifestyle Diseases?
Some people feel guilty or ridiculed when they hear that the problem they have is a lifestyle disease. I can see why. Calling these problems lifestyle diseases can be interpreted as suggesting that you have caused your own illness. Even though lifestyle and behavior are critical components, they certainly aren’t the only factors involved. Many people manage their weight well, eat wholesome diets, lead physically active lives, and still develop prediabetes and type 2 diabetes. Genetic and environmental factors are at play. These factors affect an individual’s weight as well. In fact, the Obesity Society has identified a long list of potential contributors to overweight and obesity that boost the risk for prediabetes and type 2 diabetes. They include medications, intestinal bacteria, medical conditions, and even being born by C-section. When you hear these conditions being called lifestyle diseases, don’t focus on the past. Instead, be a forward-thinker and focus on the contribution healthful lifestyle changes can make in your future. I prefer to say that these conditions have lifestyle solutions and management strategies instead of saying that they are lifestyle diseases.
Insulin Resistance and Loss of Insulin Production: Hallmarks of Prediabetes and Type 2 Diabetes
Although they often seem to, prediabetes and type 2 diabetes do not come out of the blue. Before developing type 2 diabetes, most people have prediabetes. And before they develop prediabetes, most people have insulin resistance and/or decreased insulin production with normal blood glucose levels. Unfortunately, for many, the first indicator that something is awry is some type of diabetes complication, for example, nerve pain or eye problems. Developing complications suggests that insulin resistance and decreased insulin production began many years earlier.
Type 2 diabetes, prediabetes, and insulin resistance are part of the same problem with varying levels of blood glucose. Typically, insulin resistance goes unnoticed for years because there are usually no symptoms and because blood glucose levels remain in the healthy range. Under normal circumstances, when glucose from your food enters the bloodstream, the β-cells of your pancreas send out insulin to usher excess glucose from the blood into various cells of the body. Insulin also tells the liver to stop releasing glucose excessively. Once inside these cells, glucose is either used for energy or stored for later use. But in the presence of insulin resistance, the cells of the liver, fat, muscle, and other organs become stubborn and do not react properly to the effects of insulin. When this happens, you have lost insulin sensitivity or have become insulin resistant. Blood glucose levels rise because of the progressive loss of insulin production in the presence of insulin resistance.
Here is the usual progression to type 2 diabetes.
1. β-Cell dysfunction often alongside insulin resistance with normal blood glucose levels. Genetics plays a big role in the development of type 2 diabetes; some people have genes that predispose the β-cells to break down. This predisposition increases the risk for the development of diabetes, especially in people whose cells become resistant to the effects of insulin. This resistance to insulin requires the β-cells of the pancreas to send out extra insulin to move glucose out of the blood and into the cells. The result is higher-than-normal insulin levels with normal blood glucose levels.
2. Prediabetes. The β-cells of the pancreas stop releasing enough insulin to maintain normal blood glucose levels. Blood glucose levels rise slightly even though insulin levels are likely still higher than normal.
3. Type 2 diabetes. The β-cells fail even more, and the pancreas is unable to keep up with the demands. There isn’t enough insulin available to keep blood glucose levels down, so they rise even higher.
Insulin Resistance Affects More than Blood Glucose Levels
Although insulin is best known for its role in controlling blood glucose levels, it actually has many roles in the body. Although cause and effect are uncertain, insulin resistance, high levels of insulin in the blood, and insufficient insulin production are often associated with other health problems, including these:
• Fatty liver
• Blood vessel dysfunction
• High blood pressure
• Low HDL (good) cholesterol levels
• Elevated triglyceride levels
• Chronic inflammation
• Increased blood clotting
These factors and others put people with prediabetes and diabetes at a higher risk of developing heart disease and having a heart attack. Thus, there’s more reason to focus on lifestyle solutions. Fortunately, the steps you take to prevent type 2 diabetes do double and triple work by helping with other health concerns.
Lifestyle Interventions to Prevent Diabetes
So far, we’ve covered statistics and health risks, but here starts the good news. From the foods you eat to the walks you take and perhaps even the hours you sleep and more, your lifestyle habits affect your well-being and the likelihood that you will avoid or slow down the transition to type 2 diabetes. It is much easier to reverse or halt the progression of prediabetes than it is to reverse or halt the progression of type 2 diabetes. If you’ve been diagnosed with prediabetes or have been told that you’re at high risk for developing type 2 diabetes, you have an opportunity to grab control of your health right now and be in greater charge of your future. Considering the scores of people with undiagnosed prediabetes, you are lucky to know about your risks. The best time to start making changes you can live with is right now! Because this problem is progressive, every day, the window of opportunity closes ever so slightly. Tomorrow is a good time, too, but today is even better. Your actions can boost insulin sensitivity and protect your insulin-producing β-cells.
Research proves lifestyle changes to be a winning strategy. The federally funded Diabetes Prevention Program (DPP) included more than 3,000 overweight people at risk for type 2 diabetes. Individuals who were enrolled in the intensive lifestyle change group reduced their risk of developing type 2 diabetes by 58% during the 3-year study. Even 10 years after the start of the study, the lifestyle interventions lowered the risk by 34%. And 15 years after the study started, the risk was still 27% lower.
And there was a bonus for the heart. Years after the start of the DPP, individuals in the lifestyle change group had better cholesterol and triglyceride levels and healthier blood pressure, even though they took fewer medications for these conditions. Plus, they showed less evidence of chronic inflammation.
Before the DPP was the Finnish Diabetes Prevention Study. Researchers in this study also found remarkable results. After only 2 years, the incidence of diabetes in the intervention group was less than half of what it was in the group who did not receive diet and lifestyle training. Not surprisingly, individuals who made the most dietary changes and lost the most weight had the greatest results.
So now you see you are in the driver’s seat. No matter where you are starting today, you can influence your future health.
Winning Strategies of the Diabetes Prevention Program
The aim of the lifestyle change group of the DPP was to help participants to lose 7% of their body weight (14 pounds for someone starting at 200 pounds) and to engage in 150 minutes of physical activity each week. Additionally, program facilitators guided participants to do the following:
• Monitor their weight regularly
• Keep track of their physical activity
• Reduce their calorie intake
• Eat a wholesome, balanced diet
• Record their food intake
• Manage stress
• Focus on stopping unhelpful negative thoughts
• Develop problem-solving skills related to healthful eating and being active
• Maintain motivation
The original program also encouraged a reduced-fat diet. That aspect is no longer part of ongoing diabetes prevention programs. Newer science tells us that the quality of the fat is far more important than the quantity of fat that we consume. Today, scientists and health care professionals encourage wholesome foods with unsaturated fat such as avocados, nuts, salmon, and liquid oils and discourage foods rich in unhealthful saturated and trans fats (see Chapter 3 for more on fats).
Metabolic Syndrome: A Related Disorder
Metabolic syndrome describes a group of risk factors for developing type 2 diabetes, heart disease, and stroke. What this underscores is that these three common health problems are related. Look at the list of five metabolic risk factors below. A person with three or more risk factors has metabolic syndrome and is at high risk for developing type 2 diabetes, heart disease, and stroke. If you research the metabolic syndrome, you may see slightly different numbers. Various organizations define metabolic syndrome differently, and there are different numbers for different ethnic groups.
1. Elevated triglyceride levels: ≥150 mg/dL or taking medication for high triglyceride levels
2. Low HDL cholesterol levels: <40 mg/dL in men and <50 mg/dL in women or taking medication to treat low HDL cholesterol levels
3. High blood pressure: top number (systolic blood pressure) ≥130 mmHg or bottom number (diastolic blood pressure) ≥85 mmHg or taking medication to treat high blood pressure
4. Elevated fasting blood glucose: ≥100 mg/dL or taking medication to lower blood glucose levels
5. Large waistline: ≥40 inches men and ≥35 inches in women (however, risk starts at smaller waistlines in some ethnic populations)
Boosting Insulin Sensitivity and Preserving Insulin Production
Boosting insulin sensitivity and boosting or preserving insulin production are keys to halting prediabetes. Here are four things to do just that. They are each covered in great detail in the coming chapters.
1. Weight loss. As seen in the DPP and other studies, losing just a little weight—not tons of weight—reverses insulin resistance and lowers the risk for developing type 2 diabetes.
2. Diet. Weight loss is very hard. If it weren’t, there would be few overweight people. It’s good news that even without weight loss, a healthful diet can help you. The American Diabetes Association notes that diets with higher intakes of nuts, berries, yogurt, coffee, and tea are associated with less risk of diabetes. Red meats and sugar-sweetened beverages are associated with an increased risk of developing the disease. There are many tips on having a healthful diet throughout this book and in Chapter 3.
3. Physical activity. It’s too bad that so many people focus on the weight loss benefits of exercise because exercise does so much more than that. Every single time you exercise, you boost insulin sensitivity. Every. Single. Time.
4. Sleep. We live in a sleep-deprived world. Unfortunately, lack of sleep hinders your body’s use of insulin. As you’ll see in Chapter 10, it’s a good idea to aim for 7–8 hours of sleep nightly.
Medical Management of Prediabetes
Medications are another tool to help prevent type 2 diabetes. The DPP found good results with the drug metformin, a common medication used to treat type 2 diabetes. Metformin is an insulin sensitizer. It helps your body use insulin more effectively. It also lowers blood glucose levels by decreasing the amount of glucose created and released by your liver.
There were three study groups in the DPP. Some participants were enrolled in the lifestyle change group. Others joined the metformin group, and the rest made up the control group and received only basic diet and exercise information. Overall metformin wasn’t as effective as intensive lifestyle modification, but the results were still worth celebrating. In the 3 years of the DPP, metformin reduced the risk of developing diabetes by 31%—a positive result, but not as impressive as the 58% reduction experienced by individuals in the lifestyle change group. After 10 years, metformin reduced the risk by 18%, and after 15 years, the drug reduced the risk by 17%. Intensive lifestyle changes still brought about more positive change, but metformin created impressive results as well, particularly among specific groups of people.
Because of the results of the DPP, the American Diabetes Association recommends that metformin therapy be considered for people who are very obese, individuals younger than 60 years, women who previously had gestational diabetes, and individuals who have A1C levels ≥6%.
Your health care provider may prescribe metformin along with lifestyle changes. Also, as research continues to find additional medications to halt the progression of prediabetes to type 2 diabetes, you may be prescribed a different medication.
Treatment for Related Obesity and Cardiovascular Risk Factors
Because weight loss is an important prevention strategy, you and your health care provider may discuss the medical management of weight loss, too. There are now several weight loss medications used in conjunction with lifestyle changes that help people lose 5–10% of their starting weight and sometimes even more. Weight loss surgery is another avenue to weight loss. Depending on the type of surgery, people lose on average 15% of their starting weight up to about one-third of their starting weight.
Finally, because both prediabetes and diabetes are linked to higher rates of heart disease, you and your health care provider must also address your blood pressure and cholesterol levels. Medications may be in order for these cardiovascular risk factors. The truly good news here is that the lifestyle changes that help prevent type 2 diabetes will also help you prevent heart disease. As new habits are formed and you become healthier, you may be able to lower the dosages of some medications or stop taking them altogether. Just don’t make changes without talking it through with a member of your health care team first.
Be Empowered
Knowledge is power, but only if you also take action. Empower yourself with both information and real change.
• Review the section Risk Factors for Prediabetes and Type 2 Diabetes and try to identify your risk factors.
• Take the online diabetes risk test. Encourage your friends and family members to do the same.
• It is rare that a person with prediabetes is aware of the condition. Ask your health care provider if you should be screened for the disorder. Encourage your friends and family members to discuss it with their health care providers, too.
• If you have prediabetes or are otherwise at high risk for developing type 2 diabetes, commit some time to work through this book. You can make a difference, beginning right now, one small step at a time.
• If you’d like additional help and accountability, ask your health care provider for a referral to a registered dietitian nutritionist.
• For a different type of accountability and for empowering messages, share your progress and setbacks on social media. Use the hashtag #LifestyleReset and tag me, @NutritionJill.