By Dr. Mercola
More than one out of three Americans aged 20 and older has prediabetes,1 a condition in which your glucose, or blood sugar, levels are higher than normal, but not yet high enough to be diagnosed as full-blown diabetes.
For those with prediabetes (86 million Americans in all), 15 percent to 30 percent will go on to develop type 2 diabetes within five years. This is virtually always preventable if you change your diet and exercise, however, which is why a diagnosis of prediabetes can be viewed as a serious warning that your lifestyle needs some attention.
Unfortunately, 90 percent of those with prediabetes don’t know they have it nor are they aware that prediabetes raises your risk of more than just type 2 diabetes.
Prediabetes Increases Your Risk of Cancer by 15 Percent
A meta-analysis that included data from nearly 900,000 people found that those with prediabetes have a 15 percent higher risk of cancer, especially cancers of the liver, stomach, pancreas, breast, and endometrium.
Excess body fat, which is known to increase both cancer and type 2 diabetes risks, is often pinpointed as the reason why people with diabetes have an increased risk of cancer, but this is only part of the equation. In fact, the association between prediabetes and cancer remained even after the researchers controlled for body mass index (BMI).
If you have prediabetes, which is conventionally diagnosed by having a fasting blood sugar between 100 and 125 mg/dl, you have developed insulin resistance and can no longer properly burn fat as your primary fuel.
Insulin, a hormone produced by your pancreas, is necessary to help sugar enter your cells (and get out of your bloodstream), but if you have higher than normal blood sugar levels, it means your pancreas isn’t making enough insulin or your cells are becoming resistant to it.
High blood sugar levels may lead to chronic oxidative stress and high blood sugar, both of which can act as carcinogens,3 but there’s even more to the story than this.
Your body may begin releasing more insulin in an unsuccessful attempt to control your blood sugar, resulting in high levels of insulin, which is common in people with prediabetes. Insulin, in turn, is likely a key factor why both diabetes and prediabetes raise your risk of cancer.
What Is The Insulin-Cancer Connection?
High levels of insulin also increase your body’s production of insulin-like growth factor 1 (IGF-1), which plays a key role in cell growth and proliferation.4 Insulin resistance may allow cancer cells to grow unchecked in your body. According to Michael Pollak, M.D., a professor at the Department of Oncology and Director of the Cancer Prevention Research Unit at McGill University:5
“We know that lots of tumors have insulin receptors and research suggests insulin plays an important role in cancer…”
In one study conducted by researchers from the University of Minnesota, women with diabetes had a 50 percent greater risk of developing colorectal cancer than women without diabetes.6
Other research has shown that people with the highest insulin levels at the time of a cancer diagnosis have significantly increased risks of cancer recurrence, as well as a greater risk of being diagnosed with a particularly aggressive form of cancer.7
Another study published in Diabetologia in May of this year found that diabetic cancer patients also have a significantly elevated risk of death.8 Diabetic patients using insulin at the time of their cancer diagnosis had a four times higher mortality rate one year after cancer diagnosis, compared to non-diabetic patients, or those who did not use insulin to control their diabetes.
While this was an observational study, which means it cannot establish causality, it is worth noting nonetheless. Inflammation also likely plays a role, as a good deal of evidence exists that some cancers are caused by chronic inflammation.
Both insulin and IGF-1 may affect chronic inflammation, as can elevated levels of uric acid (often caused by poor diet). If you have high uric acid levels, your risk of insulin resistance, obesity, and diabetes also increases, bringing us back full circle.
Your Health Is at Risk if You Have Elevated Insulin (and Leptin) Levels
Conventional medicine describes diabetes as a disease characterized by elevated blood sugar. This “dysregulation of blood sugar control” is typically explained as “an inability of your body to produce enough insulin.”
The reality, however, is that type 2 diabetes is NOT the result of insufficient insulin production. It’s actually the result of too much insulin being produced on a chronic basis primarily from eating the high carbohydrate, low-fat diet recommended by the federal government.
This overwhelms and “deafens” your insulin receptors, hence the term “insulin resistance.” It’s the chronically elevated insulin levels that make your body “resistant” to understanding the signals sent by the insulin. This also occurs with leptin, a hormone that helps you regulate your appetite. When your leptin levels rise, it signals your body that you’re full, so you’ll stop eating.
However, as you become increasingly resistant to the effects of leptin, you end up eating more and gaining weight. Most overweight Americans have some degree of insulin and leptin resistance, as do people with diabetes and pre-diabetes.
Now remember, when your blood sugar becomes elevated, insulin is released to direct the extra energy into storage—the majority of which is stored as fat, and leptin is produced in these fat cells. The more fat you have, the more leptin is produced. Furthermore, as the sugar gets metabolized in your fat cells, the fat releases further surges in leptin.
This is why I typically talk about insulin and leptin resistance, as they work in tandem. Moreover, leptin is largely responsible for the accuracy of insulin signaling and whether or not you become insulin-resistant. If you’re insulin resistant, you’re more than likely leptin resistant as well, especially if you’re overweight or obese.
This is because when you develop leptin resistance, your brain can no longer hear leptin’s signals, resulting in chronic hunger, overeating, inability to properly burn fat and, typically, obesity. Pre-diabetes, insulin resistance, and ultimately type 2 diabetes, follow suit.
As explained by Dr. Ron Rosedale, the high insulin component of type 2 diabetes is responsible for much of its damage, including accelerated aging, chronic disease, and complications (which is why treating type 2 diabetes with insulin typically causes far more harm than good):
“…increased rates of chronic diseases caused by taking insulin may be because it is doing exactly the opposite of what has been shown in many studies to reduce cancer, total mortality, and extend lifespan; reducing insulin.
In fact, T2 diabetes is often considered to be a model of accelerated aging because of the high insulin. In other words, treating diabetics by overly raising insulin, either with drugs or insulin itself, is only further accelerating their aging, associated chronic diseases, and death, and should be considered malpractice.”
Good News — Prediabetes Is Easy to Reverse Without Drugs
If you’ve been diagnosed with prediabetes, consider yourself lucky. You have just received a warning that many people don’t get (and instead progress straight to type 2 diabetes). Now you can take steps to reverse the condition and reclaim your health. The following nutrition and lifestyle modifications should be the foundation of your diabetes prevention and treatment plan, regardless of whether you have prediabetes or diabetes. It will be important to monitor your fasting insulin level, which should be between 2 and 4.
The higher your level, the greater your insulin resistance and the more aggressive you need to be in your treatment plan, especially when it comes to altering your diet. If you want the short version… simply swapping processed foods for whole organic foods lower in sugar and sugar-forming carbohydrates — combined with a few minutes of daily exercise — will quickly put you on the road to reversing prediabetes. See my nutrition plan for a healthy eating guide. For more specifics, read my diabetes prevention (and treatment) plan that follows.
- Incorporate intermittent fasting.
I strongly recommend incorporating intermittent fasting. This effectively mimics the eating habits of our ancient ancestors, who did not have access to grocery stores or food around the clock. They would cycle through periods of feast and famine, and modern research shows this cycling produces a number of biochemical benefits, including improved insulin/leptin sensitivity, lowered triglycerides and other biomarkers for health, and weight loss. Intermittent fasting is by far the most effective way I know of to shed unwanted fat and eliminate your sugar cravings. Keep up your intermittent fasting schedule until your insulin/leptin resistance improves (or your weight, blood pressure, cholesterol ratios, or diabetes normalizes). After that, you only need to do it “as needed” to maintain your healthy state.
- Swap out processed foods, all forms of sugar—particularly fructose—as well as all grains, for whole, fresh food.
Fructose, grains, and other sugar-forming starchy carbohydrates are largely responsible for your body’s adverse insulin reactions, and all sugars and grains—even “healthy” grains such as whole, organic ones—need to be drastically reduced. If you’re insulin/leptin resistant, have prediabetes, diabetes, high blood pressure, heart disease, or are overweight, you’d be wise to limit your total fructose intake to 15 grams per day until your insulin/leptin resistance has resolved. For all others, I recommend limiting your daily fructose consumption to 25 grams or less to maintain optimal health. The easiest way to accomplish this is by swapping processed foods for whole, ideally organic, foods.
This means cooking from scratch with fresh ingredients. Processed foods are the main source of all the primary culprits, including high fructose corn syrup and other sugars, processed grains, trans fats, artificial sweeteners, and other synthetic additives that may aggravate metabolic dysfunction. Besides fructose, trans fat (NOT saturated fat) increases your risk for diabetes by interfering with your insulin receptors. Healthy saturated fats do not do this. Since you’re cutting out a lot of energy (carbs) from your diet when you reduce sugars and grains, you need to replace them with something. The ideal replacement is a combination of:
- Low-to-moderate amount of high-quality protein. Substantial amounts of protein can be found in meat, fish, eggs, dairy products, legumes, and nuts. When selecting animal-based protein, be sure to opt for organically raised, grass-fed or pastured meats, eggs, and dairy, to avoid potential health complications caused by genetically engineered animal feed and pesticides. Most Americans eat far too much protein, so be mindful of the amount! I believe it is the rare person who really needs more than one-half gram of protein per pound of lean body mass. Those that are aggressively exercising or competing and pregnant women should have about 25 percent more, but most people rarely need more than 40-70 grams of protein a day.
To determine your lean body mass, find out your percent body fat and subtract from 100. This means that if you have 20 percent body fat, you have 80 percent lean body mass. Just multiply that by your current weight to get your lean body mass in pounds or kilos. To determine whether you’re getting too much protein, simply calculate your lean body mass as described above, then write down everything you’re eating for a few days, and calculate the amount of daily protein from all sources. You can use the chart below to help determine the grams of protein in your food.
| Red meat, pork, poultry, and seafood average 6-9 grams of protein per ounce. An ideal amount for most people would be a 3-ounce serving of meat or seafood, which will provide about 18-27 grams of protein | Eggs contain about 6-8 grams of protein per egg. |
| Seeds and nuts contain on average 4-8 grams of protein per quarter cup | Cooked beans average about 7-8 grams per half cup |
| Cooked grains average 5-7 grams per cup | Most vegetables contain about 1-2 grams of protein per ounce |
- As much high-quality healthy fat as you want (saturated and monounsaturated). For optimal health, most people need upwards of 50-85 percent of their daily calories in the form of healthy fats. Good sources include coconut and coconut oil, avocados, butter, nuts, and animal fats. (Remember, fat is high in calories while being small in terms of volume. So when you look at your plate, the largest portion would be vegetables.)
- As many non-starchy vegetables as you want
- Exercise regularly and intensely.
Studies have shown that exercise, even without weight loss, increases insulin sensitivity. High intensity interval training (HIIT), which is a central component of my Peak Fitness program, has been shown to improve insulin sensitivity by as much as 24 percent in just four weeks.
- Improve your omega-3 to omega-6 ratio.
Most Americans are eating far too many processed and damaged omega-6 fats and far too little omega-3 fats. The main sources of omega-6 fats are corn, soy, canola, safflower, peanut, and sunflower oil (the first two of which are typically genetically modified as well, which further complicates matters). Our bodies evolved for an optimal 1:1 ratio of omega-6 to omega-3. However, our ratio has deteriorated to between 20:1 and 50:1 in favor of omega-6. To remedy this, reduce your consumption of vegetable oils (this means not cooking with them and avoiding processed foods), and increase your intake of animal-based omega-3, such as krill oil. Vegetable-based omega-3 is also found in flaxseed oil and walnut oil, and it’s good to include these in your diet as well. Just know they cannot take the place of animal-based omega-3s.
- Maintain optimal vitamin D levels year-round.
Vitamin D is highly beneficial for diabetes. The ideal way to optimize your vitamin D level is by getting regular sun exposure or by using a tanning bed. As a last resort, consider oral supplementation with regular vitamin D monitoring to confirm that you are taking enough vitamin D to get your blood levels into the therapeutic range of 50-70 ng/ml. Also please note that if you take supplemental vitamin D, you create an increased demand for vitamin K2.
- Get adequate high-quality sleep every night.
Insufficient sleep appears to raise stress and blood sugar, encouraging insulin and leptin resistance and weight gain. In one 10-year long study of 70,000 diabetes-free women, researchers found that women who slept less than five hours or more than nine hours each night were 34 percent more likely to develop diabetes symptoms than women who slept seven to eight hours each night.9 If you are having problems with your sleep, try the suggestions in my article “33 Secrets to a Good Night’s Sleep.” Strive for eight hours of sleep a night.
- Maintain a healthy body weight.
If you incorporate the diet and lifestyle changes suggested here you will greatly improve your insulin and leptin sensitivity, and a healthy body weight will follow in time. As a general guideline, you might find a hip-to-waist size index chart helpful. This is far better than BMI for evaluating whether or not you may have a weight problem, as BMI fails to factor in both how muscular you are and your intra-abdominal fat mass (the dangerous visceral fat that accumulates around your inner organs), which is a potent indicator of leptin sensitivity and associated health problems.
- Optimize your gut health.
Your gut is a living ecosystem, full of both good bacteria and bad. Multiple studies have shown that obese people have different intestinal bacteria than lean people. The more beneficial bacteria you have, the stronger your immune system will be and the better your body will function overall. Fortunately, optimizing your gut flora is relatively easy. You can reseed your body with good bacteria by regularly eating fermented foods (like natto, raw organic cheese, miso, and cultured vegetables).