Prediabetes is a very early form of diabetes. The first thing you should know about prediabetes is that it is reversible and does not have to lead to full blown diabetes. The second thing you should know about prediabetes is that you –and really only you—have the power to reverse it. How can you do that? By incorporating some significant dietary and lifestyle changes into your life—these are significant changes, but not terribly difficult ones. But first, some basic information so that you understand why these changes can change a prediabetic condition to a non-diabetic condition.
The Basics of Prediabetes
A person with prediabetes has levels of blood sugar that is higher than normal, but the levels of blood glucose (sugar) are not quite high enough to be confidently diagnosed as diabetes. But, anyone with consistently higher levels of fasting blood glucose has a higher risk of developing Type 2 Diabetes (T2D)—about 15-30% of people with prediabetes develop Type-2 diabetes. In prediabetes, the cells of the body do not respond effectively to insulin– they are resistant to the insulin. Because the cells of the body are resistant, they don’t absorb sugar from the blood– these cells are essentially “ignoring” the signals from insulin.
How Prediabetes Can Develop
Every cell in our body uses glucose (sugar) for producing the energy needed for the cells to do their jobs. This glucose is derived from the foods we eat, primarily from carbohydrates.
Carbohydrates are one of the main groups of nutrients—the other are fats and proteins. Carbohydrates are molecules composed of chains of various different sugars, including glucose. The glucose is derived as a digestive breakdown product from carbohydrates and is absorbed by the digestive system into the blood. At this point, the glucose is commonly known as “blood sugar” and is the substance measured to determine your blood sugar levels. To understand prediabetes, you first should understand about the different types of carbohydrates and about insulin.
There are essentially two classes of carbohydrates1:
- Complex carbohydrates have many chains and often consist of many branches of sugars linked together. Complex carbohydrates are found in unprocessed whole grains, fruits, vegetables, beans and legumes. The fact that they are unprocessed is important because processing breaks down complex carbohydrates into simple carbohydrates—basically, processing can be thought of as an industrial “pre-digestive” step. Complex carbohydrates are also called starches—the indigestible carbohydrates are known as fiber. Complex carbohydrates take longer to be digested (chemically broken down to the simple carbohydrates) but provide more potential for energy over a longer period of time, resulting in fewer highs or lows in blood sugar.
- Simple carbohydrates have shorter, unbranched chains of sugars linked together. Table sugar (sucrose) is a simple sugar made up of one molecule of glucose and one molecule of fructose. Lactose or milk sugar is also made up of two units—glucose and galactose. These simple carbohydrates are fast sources of energy because they are easily and rapidly digested. High Fructose Corn Syrup (HFCS) is a simple sugar and is added to a great number of processed foods. Recently, the ingestion of HFCS (by consuming soft drinks and other beverages with HFCS added) has, like the over-ingestion of sugar, been associated with increased risk of insulin resistance, Type 2 Diabetes, cardiovascular disease and obesity2. Simple sugars can cause high levels of blood glucose.
While diabetes has been known for thousands of years, the rate of diabetes has risen dramatically in the last 200 years. This rise in the rate of prediabetes and diabetes essentially parallels the rise in the industrialization of food and the amount of processed foods that we eat. Processing adds simple sugars to our foods and the theory is that the greater the amount of simple sugars that we ingest, the greater the risk of prediabetes. In fact, there are many scientists, doctors and researchers who believe that the simple sugars act as a drug—they show certain drug characteristics such as addiction and tolerance development4,5.
What is Insulin? How Does Insulin Affect Blood Sugar?
Hormones are chemical “messengers” that are produced by endocrine glands. Insulin is a hormone that is produced by the pancreas. Insulin is the primary chemical messenger, signaling the cells to absorb the glucose into the cells. If the cells respond to insulin correctly, they begin to transport glucose into their interior and the levels of glucose in the blood—your blood sugar or blood glucose levels—should begin to decrease.
In addition, our bodies tend to use its chemical messengers to send many different messages at the same time. At the same time that insulin is telling the cells of the body to take up glucose, it is also involved in signaling the liver to take the glucose from the blood. Liver cells then transform it into glycogen, the storage form of glucose. Insulin is involved in a number of other functions including the metabolism of fats and proteins. For example, insulin can increase the production of fatty acids in the liver and slows down the breakdown of fat in fatty tissues.
When the Message from Insulin is “Ignored”
Prediabetic cells become insulin resistant and don’t pay attention to or can’t react to the signal from insulin. This is the beginning of the long process that can eventually lead to prediabetes and then, potentially diabetes, metabolic syndrome, heart disease and obesity.
At first, some cells begin to ignore the insulin signals. Then, more and more cells ignore the insulin. This ends up causing even more insulin to be secreted from the pancreas because the signal for insulin release is the level of blood sugar. High levels of blood sugar tell the pancreas it needs to produce insulin. So, more and more insulin ends up being secreted but fewer and fewer cells are responding properly. This results in an increased level of glucose in the blood. The pancreas will then respond by producing more and more insulin, in an effort to “push” the sugar molecules into the cells. A sort of vicious cycle has begun—the pancreas keeps getting the signal to produce more insulin to try and push the sugar from the blood into the cells of the body—the cells won’t take up the glucose and the pancreas keeps producing even more insulin.
Since, as mentioned, insulin has a number of functions, the high insulin levels end up stimulating the conversion of the high levels of blood glucose in the blood into fatty acids and then fat. On the level of the whole body, this insulin resistance can show up in early symptoms of prediabetes, though, for most people, there are no obvious symptoms of prediabetes. The following are at least some ways that symptoms of prediabetes can appear.
- Since the glucose isn’t going into the cells as it is supposed to, the cells aren’t getting enough energy and the body as a whole reads this as “I’m hungry and I need to eat!” This translates as one of the symptoms of prediabetes—a sense of increased hunger.
- Another symptom of prediabetes is losing weight even while you are hungrier and eating more—this may be because while you are eating, your cells are not actually getting the fuel they need, so they start using the stored fat as a source of energy. However, fat tends to be inflammatory and also tends to increase your body’s resistance to insulin. All this can set up a state of chronic inflammation and disorders such as T2D, obesity, metabolic syndrome and heart disease.
- Other symptoms of prediabetes include:
- Increased thirst and increased frequency of urination
- Increased fatigue (possibly because the cells of your body are not getting the fuel (glucose) that they need).
Risk Factors for Prediabetes
There are a number of unanswered questions about prediabetes and how, exactly, it progresses to diabetes. We do know that there are certain risk factors for developing prediabetes. These include6:
- Weight: People who are heavier—especially heavier around the midsection or waist—tend to have a higher risk for prediabetes. One simple way of determining this is to measure the waist (in inches). The risk of prediabetes is increased in women with a waist measurement of > 35 inches and in men with a waist measurement of > 40 inches.
- Physical Inactivity: People who tend to do little physical activity tend to be heavier and this has long been thought to be an indirect way that low levels of physical activity put a person at risk for prediabetes. But, since exercise has been shown to reduce inflammation and since inflammation is always a part of prediabetes, the lack of physical activity may increase the risk of prediabetes more directly by increasing the amount of inflammation in the body.
- Genetics or Family History: Your heredity can be very important as a risk factor. If a close family member had or has prediabetes or diabetes, you have a greater risk of prediabetes yourself.
- Ethnic Background: People of African, Hispanic, North American Native and Asian backgrounds have a higher risk of prediabetes.
- Age: After the age of 45, your risk of prediabetes begins to increase. After the age of 65, the risk starts increasing more dramatically.
- Medical History: Your personal medical history can increase your risk of prediabetes. For example, if you have a history of high blood pressure, high levels of LDL-cholesterol (or low levels of HDL-Cholesterol), a history of polycystic ovary syndrome (PCOS) or have had gestational diabetes, your risk of prediabetes is increased.
Lab Tests for Prediabetes
Quite often, there are no clear symptoms of prediabetes. If you see a physician regularly and have your blood tested, your physician may notice that your blood sugars tend to be on the high side (but not high enough to diagnose T2D). Prediabetes can be diagnosed, however, using either the A1c test, a fasting blood glucose test or an oral glucose tolerance test (OGTT).4
- Fasting blood sugar levels between 100-125 mg/dL are suggestive of prediabetes.
- Another blood test, the A1c test, measures how your body has been handling sugars for the past 3 months and can be used to diagnose prediabetes.
- The A1c level for insulin resistance and prediabetes is generally considered to be between 5.7- 6.4%.
- Type 2Diabetes is usually diagnosed if the A1c is greater than 6.5%.
- The A1c level for insulin resistance and prediabetes is generally considered to be between 5.7- 6.4%.
- An oral glucose tolerance test (OGTT) can be used to diagnose prediabetes. In this test, first, you have your blood drawn to measure blood sugar levels. You will then be given a beverage that is very sweet. After 2 hours, your blood is drawn again and the blood sugar is measured again. This test determines how well your body handles sugars. (The blood sugar levels should go down within 2 hours. If they do not go down significantly, this can be a sign that you may be insulin resistant or prediabetic. In prediabetes, the blood sugar levels will be between 140-199 mg/dL. In people without prediabetes, the blood sugar levels will be less than 139mg/dL).
What can YOU do to Prevent or Reverse Prediabetes
The answer to this question is straightforward and may be simple for some—however, putting this answer to work for you requires some commitment and dedication because you are likely to have to change some habits, and that, honestly, can be sometimes difficult.
Most simply put, prediabetes can be reversed by losing weight by changing the way you eat and by increasing you level of exercise. 6,7
Controlling Prediabetes with Diet
Food is not what it used to be. Until recently, many of us grew much of our own food or bought it from the farmer down the road. Today, the food that one buys may have come from another continent or from another part of the country. Most food that is available on most grocery shelves is boxed, packaged, processed and preserved. The meats contain antibiotics, hormones and the animals from which these meats are derived do not eat their natural foods and do not get to roam freely and may not be completely healthy. Crops may be grown in depleted soils, forced to grow by the use of fertilizers and soil additives. To put it simply, our food just ain’t what it used to be! On the more individual level, many people don’t eat many fruits and vegetables, or eat a limited number. Many people have little time to cook and use prepared or fast foods. Large food manufacturers and processors add all sorts of additive, preservatives and sugars to foods—this extra sugar tastes good to many people and the foods are often easier to prepare.
Prediabetes has been recognized only in the last few decades, but it is believed that prediabetes is associated with too many simple sugars in the diet and can be reversed with diet, nutrition and exercise.
To reverse prediabetes, dietary approaches emphasize whole foods (organic when at all possible), complex carbohydrates and high density nutrients including proteins and healthy fats. These guidelines are essentially part of an anti-inflammatory diet which is gaining more and more acceptance with physicians– nutritionists have been “on board” for a much longer time.2 Following the dietary rules below can help you reverse prediabetes resistance and, as a bonus, it is very likely that it will help you lose extra weight!
Here are some “rules” to follow:
- Buy whole foods (whole grains, fresh fruits and vegetables) as opposed to processed foods.
- The reasoning is that processing removes nutrients, adds preservatives and additives and sometimes huge amounts of sugars. For example, 1 teaspoon of sugar is equal to about 4 grams of sugar. One 6 ounce serving of low-fat yogurt has 28 grams or 7 teaspoons of sugar. On the other hand, one tablespoon of pure honey has 16 grams of sugar.
- Cook fresh food from scratch as much as possible—this helps preserve the nutrients.
- Include organic foods as much as possible. Here, the rationale is that many chemicals are though to cause inflammation. Since inflammation is always linked to prediabetes, you want to limit that inflammation as much as possible.
- 90-95% of the carbohydrates you eat should be complex carbohydrates:
- Complex carbohydrates are found in whole, unprocessed foods such as whole grains, peas, lentils, beans, fruits and vegetables.
- A good rule of thumb to follow is “No white foods” – no white bread, white pasta or white rice. You should also avoid candies, cookies, cakes and other pastries.
- Increase the amount of fiber in your diet. Try to include, for example, a tablespoon of ground flaxseeds at every meal. You can add ground flaxseeds to salads, vegetables, side dishes or soups.
- Limit red meats and increase the amounts of fish and skinless poultry you eat.
- Look for wild-caught fish such as salmon, cod, haddock and tuna– these fish are good sources of omega-3 fatty acids. The omega-3 fatty acids are essential for health and are anti-inflammatory foods.
- Increase the amounts and varieties of fruits and vegetables that you eat.
- The sugars in fruit are combined with the fiber– and this means that the absorption of sugars from the fruit are slowed down.
Increasing your physical activity level just a relatively moderate amount can help reverse prediabetes. There is no need to train for a marathon! All you really have to do is to start walking more, climbing more stairs, doing more outdoor activities, hiking, gardening, aerobics, Tai chi, yoga, using an elliptical, rowing machine or using a stationary bicycle. This can be as simple as parking at the far end of a parking lot or using the stairs instead of an elevator or escalator. You goal should be 30 minutes of moderate activity (mixing the activities if you want) for at least 5 days a week. It is important to find some activity that YOU like and that YOU can commit to! Start slowly and work your way into greater activity. Don’t forget to stretch and warm up, especially if you are trying to jump right into it! You can also think about joining a gym and getting a personal trainer. Finally, make certain you know and understand any physical conditions that may limit your activity.
- Polonsky, K. The Past 200 Years in Diabetes, NEJM, 2012; 367:1332-1340,
- Liester, Mitchell B., and Jenna D. Moore-Liester. “Is Sugar a Gateway Drug?” Journal of Drug Abuse 1.1 (2015): 8.
Williamson, Jeff D., Lenore J. Launer, and Michael E. Miller. “Why are we consuming so much sugar despite knowing too much can harm us?.” JAMA 175.1 (2015): 145.