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1 in 5 Adolescents Is Prediabetic

Analysis by Dr. Joseph Mercola Fact Checked

prediabetes in teens

Story at-a-glance -

  • In the U.S., about 1 in 5 adolescents and 1 in 4 young adults has prediabetes, according to a study by U.S. CDC scientists
  • Prediabetes is a condition characterized by higher-than-normal blood sugar levels, which increases your risk of developing Type 2 diabetes, chronic kidney disease and cardiovascular disease
  • Among adolescents ages 12 to 18, 18% had prediabetes, as did 24% of young adults, who were between the ages of 19 and 34
  • Prediabetes was more common in males and people with obesity
  • Those with prediabetes had higher rates of other risk factors for Type 2 diabetes and heart disease, including high blood pressure, increased abdominal fat and lower insulin sensitivity

In the U.S., about 1 in 5 adolescents and 1 in 4 young adults has prediabetes, according to a study by U.S. CDC scientists. Prediabetes is a condition characterized by higher-than-normal blood sugar levels, which increases your risk of developing Type 2 diabetes, chronic kidney disease and cardiovascular disease.1

Its prevalence has increased in U.S. adolescents in the last decade, leading researchers to survey 5,786 youth to monitor the trend. Among adolescents aged 12 to 18, 18% had prediabetes, as did 24% of young adults, who were between the ages of 19 and 34.2

Prediabetes Affects an Alarming Number of Youth

In the U.S., the incidence of Type 2 diabetes is on the rise, projected to increase more than fourfold in the coming decades.3 Prediabetes is a warning sign of Type 2 diabetes, one that can be reversed before lasting damage is done if attention is made to healthy diet and exercise.

A number of concerning findings were revealed in the study, which used data from the 2005 to 2016 National Health and Nutrition Examination Survey, including:4,5

Adolescents and young adults with prediabetes were more likely to be male; in fact, males were nearly twice as likely to have prediabetes than females

Those with obesity were more likely to have prediabetes ((25.7% versus 16.4% in adolescents and 36.9% versus 16.6% in young adults)6

Prediabetes was more common in Hispanic young adults than white young adults

Those with prediabetes had higher rates of other risk factors for Type 2 diabetes and heart disease, including high blood pressure, increased abdominal fat and lower insulin sensitivity

"Our study found that prediabetes is highly prevalent in U.S. adolescents and young adults, especially in male individuals and in people with obesity," the researchers of the featured study explained.

"Moreover, adolescents and young adults with prediabetes also present an unfavorable cardiometabolic risk profile and are therefore at increased risk of not only developing type 2 diabetes, but also cardiovascular diseases."7

Prediabetes Is Diabetes

A diagnosis of prediabetes may be a matter of semantics, as the majority of Americans are likely prediabetic and suffering from what the late Dr. Joseph Kraft, author of "Diabetes Epidemic and You: Should Everyone Be Tested?" called "diabetes in situ."

Prediabetes is defined as an elevation in blood glucose over 100 milligrams per deciliter (mg/dl) but lower than 125 mg/dl, at which point it becomes full-blown Type 2 diabetes.8 According to the CDC, an estimated 84 million American adults — about 1 in 3 — are prediabetic, and most (90%) are unaware of this fact.9

That being said, any fasting blood sugar regularly over 90 suggests insulin resistance in my book. What's more, Kraft suggested 80% — 8 out of 10 — of Americans are insulin resistant. Based on data from 14,000 patients,10 Kraft, former chairman of the department of clinical pathology and nuclear medicine at Presence Saint Joseph Hospital, developed a powerful predictive test for diabetes.11

He would have the patient drink 75 grams of glucose and then measure their insulin response over time, at half-hour intervals for up to five hours. Interestingly, he noticed five distinctive patterns suggesting a vast majority of people were already diabetic, even though their fasting glucose was normal.

Only 20% of patients had a pattern signaling healthy post-prandial insulin sensitivity and low diabetes risk, which means 80% were prediabetic or had "diabetes in situ." As explained by

"If you simply wait until blood glucose is elevated, then you have [Type 2 diabetes], no question. But if you have normal blood sugars, then you may still be at risk of diabetes (prediabetes).

So, we give a big load of glucose and see if the body is able to handle it … If the body responds by very high secretion of insulin, this will force the blood glucose into the cell and keep the blood glucose normal.

But this is not normal. It's like the trained athlete who can easily run 10K in one hour and the untrained athlete who must dig deep and use all his effort to do so. Those people who need to produce prodigious amounts of insulin to force the glucose back to normal are at high risk [for diabetes]."

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What Are the Risks of Prediabetes?

There are no obvious symptoms of prediabetes, an early state of insulin resistance known as impaired glucose tolerance; this is why so many people are affected but don't know it. There are, however, risk factors for the condition, which include:13

Being overweight

Being 45 years or older

Family history of Type 2 diabetes

Inactivity (exercise less than three times a week)

Having had gestational diabetes

Having polycystic ovary syndrome

Having a large waist size (larger than 40 inches for men or 35 inches for women) or eating a diet high in processed grains and sugars is also associated with a higher risk of prediabetes.14 One of the greatest risks of prediabetes is that it increases your risk of developing Type 2 diabetes, which is a leading cause of death in the U.S.

In fact, life expectancy recently declined in the U.S. for the first time in two decades,15 and Type 2 diabetes is a major factor in the decline.16 Researchers noted, "Diabetes may represent a more prominent factor in American mortality than is commonly appreciated, reinforcing the need for robust population-level interventions aimed at diabetes prevention and care."17

However, prediabetes can also be dangerous even if you haven't progressed to Type 2 diabetes. Prediabetes is associated with unrecognized heart attacks and kidney damage, for instance,18 and also means you're at least mildly insulin resistant.

The higher your insulin resistance, the worse markers such as fasting insulin, triglyceride-HDL ratio and HbA1c will be, suggesting you're at increased risk for a number of chronic diseases, including not only diabetes but also heart disease, metabolic syndrome, cognitive decline and cancer. The good news is that insulin resistance, and thereby prediabetes, is one of the easiest health problems to correct.

How to Determine if You're Prediabetic

If you're reading this and aren't sure what your fasting insulin and glucose levels are, these are blood tests I recommend receiving annually. Your fasting insulin level reflects how healthy your blood glucose levels are over time.

A normal fasting blood insulin level is below 5, but ideally you'll want it below 3. A fasting glucose level below 100 mg/dl suggests you're not insulin resistant according to conventional recommendations, but I recommend aiming for a fasting (when you wake up) level below 90 mg/dL.

A fasting level between 100 and 125 confirms you have prediabetes. Your blood sugar is measured through a glucose test, of which there are four types:

  1. Fasting plasma glucose test — When you fast overnight and take your blood sample in the morning
  2. Oral glucose tolerance test — Similar to the fasting blood sugar test, overnight fasting is required for this, and the person's fasting blood sugar level is measured. Afterward, a sugary liquid is provided and the levels are then tested for the next two hours
  3. Hemoglobin A1C test — This test checks the percentage of blood sugar attached to the hemoglobin and will indicate your average blood sugar level for the past two to three months
  4. Random plasma glucose test — This makes use of a blood sample that is taken at a random time

You could also do 24-hour continuous glucose monitoring, which I've done in the past, although it's pricey and probably not necessary for most people.

At the time, I used a Dexcom monitor, which involves inserting a sensor beneath your skin for a week, which takes continuous glucose readings every few minutes. It really helped me fine-tune and evaluate how different foods impacted my glucose levels, and helped me understand the importance of feast-famine cycling.

Timing Your Meals to Resolve Prediabetes

Intermittent fasting, i.e., the cycling of feast (feeding) and famine (fasting) mimics the eating habits of our ancestors and restores your body to a more natural state that allows a whole host of metabolic benefits to occur.19

With regard to insulin resistance, research shows intermittent fasting promotes insulin sensitivity and improves blood sugar management by increasing insulin-mediated glucose uptake rates.20 While there are a number of different intermittent fasting protocols, my preference is fasting daily for 18 hours and eating all meals within a six-hour window.

If you're new to the concept of intermittent fasting, consider starting by skipping breakfast and have your lunch and dinner within a six-hour timeframe, say 11 a.m. and 5 p.m., making sure you stop eating three hours before going to bed. It's a powerful tool that can work even in lieu of making other dietary changes.

In one study, when 15 men at risk of Type 2 diabetes restricted their eating to a nine-hour window, they lowered their mean fasting glucose, regardless of when the "eating window" commenced.21

What you eat is also important. I recommend adopting a cyclical ketogenic diet, which involves radically limiting carbs (replacing them with healthy fats and moderate amounts of protein) until you're close to or at your ideal weight, ultimately allowing your body to burn fat — not carbohydrates — as its primary fuel.

Reverse Prediabetes and Type 2 Diabetes

While many people — young and old alike — are facing prediabetes and Type 2 diabetes, these conditions can be turned around. Along with intermittent fasting and a cyclical ketogenic diet, the tips that follow will help you reverse prediabetes and prevent Type 2 diabetes, while helping you avoid the chronic diseases related to them:

Limit added sugars to a maximum of 25 grams per day. If you're insulin resistant or diabetic, reduce your total sugar intake to 15 grams per day until your insulin/leptin resistance has resolved (then it can be increased to 25 grams) and start intermittent fasting as soon as possible.

Limit net carbs (total carbohydrates minus fiber) and protein and replace them with higher amounts of high-quality healthy fats such as seeds, nuts, raw grass fed butter, olives, avocado, coconut oil, organic pastured eggs and animal fats, including animal-based omega-3s. Avoid all processed foods, including processed meats. For a list of foods that are particularly beneficial for diabetics, please see "Nine Superfoods for Diabetics."

Get regular exercise each week and increase physical movement throughout waking hours, with the goal of sitting down less than three hours a day.

Get sufficient sleep. Most need right around eight hours of sleep per night. This will help normalize your hormonal system. Research has shown sleep deprivation can have a significant bearing on your insulin sensitivity.

Optimize your vitamin D level, ideally through sensible sun exposure. If using oral vitamin D3 supplementation, be sure to increase your intake of magnesium and vitamin K2 as well, as these nutrients work in tandem, and monitor your vitamin D level.

Optimize your gut health by regularly eating fermented foods and/or taking a high-quality probiotic supplement.