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Is your New Year’s resolution to get healthier—physically or mentally? Great!

Now, how are you going to do it? Exercise? Meditation? Diet? How do you know which strategies are worth your time, energy, and money?

If you’re thinking of changing your diet, which diet are you going to try? Mediterranean? Plant-based? Low-fat? Ketogenic? Paleo? Weight Watchers? Gluten-free?

There are lots of ways to get healthier, so you can start wherever you want. The good news is that no matter which approach you choose, you can use this simple, magical, in-home tool to stay motivated and track your progress in real time: a glucometer.

A glucometer is an inexpensive, hand-held meter that measures your blood glucose (sugar) level.

Everybody Needs Access to a Glucometer

—and I do mean everybody: extremely fit people, children, skinny people, people who have no health problems, people who feel great and have lots of energy, people who just went to the doctor five minutes ago and were told their blood sugar is normal and they don’t have any signs of diabetes—everybody.

Why? Because what you don’t know about your blood sugar levels can hurt you, and even kill you. This is no exaggeration. You could deteriorate slowly over decades and eventually die of Alzheimer’s disease, or you could literally drop dead of a heart attack tomorrow.

How do you protect yourself from doom and gloom? All you need is a glucometer and compatible test strips, and all you have to do is check your blood glucose one hour after meals.

A glucometer gives you a window into your metabolism and can help show you if you have “insulin resistance.” Insulin resistance plays a major role in the development of nearly every chronic disease we fear: type two diabetes, obesity, heart disease, Alzheimer’s disease, polycystic ovarian syndrome/infertility, non-alcoholic fatty liver disease, erectile dysfunction, certain forms of cancer, and many other conditions, including most psychiatric disorders. Who wants any of these? Nobody.

Insulin resistance simply means that your insulin signaling system isn’t working as well as it should. Most people think of insulin as simply a blood sugar regulator—but it has many other responsibilities. Insulin is a master hormone that helps to control the metabolism of nearly every cell in your brain and body, so if it’s not working properly, it can have dire consequences for all aspects of your health.

Insulin resistance, which is sometimes called “pre-diabetes” or “poor carbohydrate tolerance” has reached epidemic proportions around the world, including in the United States. More than 50% of us now have insulin resistance, although many of us don’t know it, because most doctors don’t know how to properly check for it.

Your Doctor Doesn’t Order the Right Tests

Unfortunately, medical clinics are far behind the times when it comes to evaluating your risk for insulin resistance and diabetes. Instead of measuring your blood sugar one hour after you eat, when it is at its peak, they usually rely on the following tests:

  • Fasting Blood Sugar (glucose)—a blood test drawn first thing in the morning, before breakfast. This is usually when your blood sugar is at its lowest, since you haven’t eaten all night.
  • Hemoglobin A1C—a blood test that estimates your average blood sugar over the past three months. This test doesn’t look at individual blood sugar readings, so it can’t tell you whether your blood sugar is rising too high after meals.

Unfortunately, these are dangerously ineffective tests, because by the time they become abnormal, your metabolism has already been badly damaged. Both of these tests typically remain stone cold normal for years while insulin resistance quietly worsens beneath the surface, undetected, slowly marching you towards type two diabetes or one of many other associated diseases [cue the Jaws theme music].

As Italian researchers explain in this 2018 study

“Postprandial hyperglycemia [high blood sugar after meals], as occurs in people with impaired glucose tolerance, has been shown to double the risk for death from cardiovascular diseases. . . Furthermore, postprandial hyperglycemia is one of the earliest abnormalities of glucose homeostasis [regulation] associated with type 2 diabetes and worsens—progressing to fasting hyperglycemia—as the condition progresses."

A Stanford University study published earlier this year found that individuals who had been assessed as low or moderate risk based on their fasting blood glucose, hemoglobin A1C and fasting insulin levels, had blood sugar spikes rising into the pre-diabetic and diabetic range after meals when tracked with a continuous blood glucose monitor. The severity of glucose spikes after meals revealed critical information that standard tests were unable to detect.

The Long, Silent Path from Insulin Resistance to Diabetes

Diabetes doesn’t happen overnight. It is preceded by many years of gradually worsening insulin resistance. The details about what exactly causes insulin resistance and how it develops are still being explored, but a consensus is emerging that our ultra-processed modern diet, which is loaded with refined carbohydrates (sugars, flours, processed cereal products, fruit juices, etc.), is largely to blame. These rapidly-digestible simple sugars flood the bloodstream with too many sugar molecules at once, placing tremendous stress on our delicate insulin signaling system to process them all.

Over time, our insulin response system begins to wear out, making it more and more difficult to keep blood sugar in a healthy range. In the early stages of insulin resistance, blood sugar can be normal most of the time except for after meals, when it will tend to rise higher than usual and stay high for a longer period of time.

People with insulin resistance (aka “pre-diabetes”) tend to have higher blood sugar and insulin levels after meals than healthy people do. There is no good in-home test yet for insulin, so checking blood sugar is your best bet. Blood sugar peaks at about one hour after eating, so this is the best time to detect problems.

In the later stages of insulin resistance, the system is so broken that blood sugar doesn’t just rise too high after meals—it stays high most of the time—even after not eating all night. This is when your “fasting blood sugar” will finally show up as abnormal—and your doctor will diagnose you with type two diabetes—severe metabolic damage that has robbed you of the ability to handle carbohydrates of all kinds—not just the refined ones.

What Should My Blood Glucose Be?

Recommendations vary, as the concept of 1-hour glucose testing is a relatively new one, so the below values are averages of cutoff values gathered from a variety of sources.

Fasting: 

Healthy  70-110 mg/dL

Pre-diabetic 110-126 mg/dL

Diabetic  >126 mg/dL

One hour after meals:

Healthy <140 mg/dL

Pre-diabetic 140-200 mg/dL

Diabetic >200 mg/dL

Knowledge is Power

If you do have insulin resistance, the best thing you can do for your health is to reduce your carbohydrate intake, because carbohydrates are what increase blood sugar and insulin levels the most—but don’t take my word for it—use a glucometer to see for yourself which foods raise YOUR blood sugar the most. Periodically testing your blood sugar provides valuable insight about which foods are working against you.

A glucometer leads you out of the darkness and into the light, giving you speedy feedback about your diet, helping you understand whether the changes you’re making are effective, holding you accountable, and keeping you motivated. Blood sugar readings improve rapidly when you make the right changes, which is gratifying and empowering.

People often ask me how much carbohydrate is safe to eat. The answer is that everyone is different. While it is perfectly safe (once weaned from mother’s milk) to consume no carbohydrate at all, most people prefer to include some carbohydrate in their diet. Testing your own 1-hour blood sugar levels can help you determine your own personal threshold.

When I first started eating a low-carbohydrate diet myself, I found it very helpful to monitor my glucose at home, because numbers don’t lie, so denial was not an option! My glucometer kept me honest.

I love recommending home glucose testing to my patients, because unlike body weight or clothing size, there is no stigma attached to glucose readings, so seeing high numbers feels safe and neutral, even for people struggling with overweight and body image concerns. Glucose readings are a much more important and accurate measure of health than body weight anyway.

What if Your Glucose Readings Are Normal?

Even if your glucose levels aren’t usually in the pre-diabetic or diabetic range, understanding what types of foods increase your blood sugar more than others can help teach you how to eat in a way that prevents insulin resistance in the future.

In this study, many people who usually had normal blood sugar readings after most meals spiked too high after eating corn flakes and milk:

“It is interesting to note that although individuals respond differently to different foods, there are some foods that result in elevated glucose in the majority of adults. A standardized meal of cornflakes and milk caused glucose elevation in the prediabetic range (>140 mg/dl) in 80% of individuals in our study. It is plausible that these commonly eaten foods might be adverse for the health of the majority of adults in the world population.”

Most of us don’t think of plain corn flakes as sugary (they only contain 3 grams of added sugar per serving), but corn flakes are made of refined corn flour, which is pure glucose. It doesn’t have to be sweet to be sugar. For more information and a list of foods containing refined carbohydrates please see http://www.diagnosisdiet.com/refined-carbohydrate-list/.

How to Get a Glucometer

If you have diabetes, glucometers and their compatible test strips are usually covered by health insurance. Unfortunately, for the millions of us who have insulin resistance or “pre-diabetes,” they are not usually covered. While glucometers themselves are inexpensive without insurance, the test strips can run into money, especially if you test frequently. The good news is once you have tested enough times to understand how to eat properly, you can test a lot less often.

There are many reviews available on line to help you decide which meter is best for you and your budget. Every monitor uses its own strips, and strips are what cost the most money, so pay attention to the price of the strips before you buy. It is truly worth investing in a glucometer for you or your family—the money you save on health expenses in the future will more than cover the cost.

More expensive but exciting new “continuous” glucose monitors are now available that take readings every few minutes, and technology is emerging to provide cutting-edge monitors made with sensors that don’t require pricking your skin.

If you can’t afford a glucometer, consider borrowing one. Sadly, so many people have diabetes now that chances are someone in your family or circle of friends has one you could use from time to time.

If you can’t access a glucometer, there are other ways to learn whether or not you have insulin resistance. See my article "How to Diagnose, Prevent and Treat Insulin Resistance," which includes a free downloadable PDF listing other helpful tests and clues to insulin resistance and an infographic to help guide your dietary changes.

The Most Valuable Tool to Get and Stay Healthy

Insulin resistance is public health enemy #1. The single most important thing you can do for your health is to determine if you have insulin resistance. Learning how your lifestyle impacts your blood sugar is one of the simplest, smartest, and most effective ways to get healthier. A glucometer will ensure that whatever diet you choose—regardless of whether it is plant-based or meat-based—is safe and healthy for your metabolism.

Here’s to your excellent health in the coming year!