Metabolic health basics: What you need to know

New to the world of metabolic health? Start here. Below we describe the basics of glucose and insulin, why metabolic health is important, and how you can improve yours.


Article highlights

  • Good metabolic health means your body can efficiently convert food into energy to power cells, while poor metabolic health means cells don't get enough energy.
  • Even before diabetes, declining metabolic health can affect physical wellbeing and energy, mood, etc.
  • Improving metabolic health can translate to benefits like sharper memory, balanced mood, endurance, less anxiety, clearer skin, and better immunity.
  • Blood sugar should stay between 70-120 mg/dL most of the day and rarely exceed 140 mg/dL for good metabolic health.
  • Insulin tells cells to absorb sugar from blood, but frequent insulin surges can cause insulin resistance where cells resist insulin's effects.

What is metabolic health?

Everything you do requires energy.

Whether you’re running, jumping, thinking, or silently sitting, your body needs a reliable power supply to carry on. It gets this supply by converting food into energy through a set of biological processes known as metabolism.

Good metabolic health means that your body can efficiently make and use energy, helping your cells—and you—function at full capacity. Poor metabolic health, by contrast, means that cells aren’t getting the energy they need, leading to a slew of mental and physical challenges.

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Why you should care

It’s easy to dismiss blood sugar levels and other metabolic health markers as relevant only to people with diabetes. But this couldn’t be further from the truth.

For starters, Type 2 diabetes—which affects 1 in 10 US adults and is the eighth leading cause of death—doesn’t come out of nowhere. Rather, it develops gradually, starting with subtle changes to your ability to generate energy from food. Long before it results in a clinical diagnosis, this decline in metabolic health affects your physical well-being and can hamper energy, mood, and other aspects of day-to-day life. Poor metabolic health also increases your risk for chronic conditions like Alzheimer’s disease, fatty liver disease, heart disease, and stroke. This is because your body’s systems don’t work independently—everything is connected.

The good news is that you can slow and even reverse this damage. By improving your metabolic health, you improve your body’s ability to make and use energy. This can translate to sharper memory, more balanced mood, improved physical endurance, less anxiety, clearer skin, improved sexual health, and a stronger immune system. This goes not just for people with diabetes or prediabetes, but for everyone who wants to maintain optimal health.

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Glucose basics

The body gets most of its energy from glucose, a kind of sugar that comes from food you eat and circulates in your blood.

After you eat carbohydrates, your body breaks them down into glucose, which enters the bloodstream. Cells then absorb glucose and use it to generate the energy they need to do their job, whether that’s contracting muscles, relaying brain messages, or fighting off infections.

If glucose powers our cells, why is high blood sugar unhealthy?

If you consume sugar more quickly than your cells can absorb it, glucose in the blood rises to unhelpful—and eventually unhealthy—levels. That’s because the excess sugar can stick to cells, making them less efficient at producing energy and performing their respective roles in the body. This causes a number of short- and long-term health consequences.

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Blood sugar levels: what’s normal?

It’s totally normal for blood sugar levels to rise and fall throughout the day. When you eat carbohydrate-containing foods (everything from bread to broccoli), blood sugar naturally increases; and as your cells take up blood sugar, levels accordingly fall. These peaks and valleys, called glycemic variability, are a normal part of metabolic function. Your body will naturally try to maintain steady blood sugar levels.

A metabolically-healthy body has low glycemic variability, meaning blood sugar changes, but not too dramatically. If, by contrast, your blood sugar rises steeply (sometimes called a glucose spike), the crash that follows can cause cravings, fatigue, and irritability. High glycemic variability has also been linked to inflammation, blood vessel damageweight gain, and more.

Though no single glucose number defines metabolic health, experts seem to agree that blood sugar should stay between 70 and 120 mg/dL for most of the day and should rarely exceed 140 mg/dL.

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How insulin fits into the picture

Insulin is a chemical messenger that, among other things, tells cells to absorb sugar from the bloodstream.

When you eat carbohydrates, your pancreas releases insulin, signaling specialized cell doors to open. Once ajar, these doors usher sugar into cells.

After you eat super sugary or carb-dense foods, your body tries to compensate by releasing extra insulin. In the short term, this works: the additional insulin opens cell doors, glucose enters, and blood sugar remains relatively stable. If you have these insulin surges too often, however, your cells can eventually become numb to insulin’s effects—a condition called insulin resistance.

Insulin-resistant cells have trouble opening their doors, even as blood sugar and insulin levels rise. This can lead to serious health consequences, including Type 2 diabetes.

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What you can do to improve your metabolic health

You can improve your metabolic health by consistently making choices that help your cells function optimally. On the nutrition front, this means limiting foods with added sugar and refined flour (think white bread, pasta, cereal, and cookies), which can cause sharp increases in blood glucose. You should also try to avoid ultra-processed food, which is full of additives and stripped of nutrients. When in doubt, eat real, minimally processed foods.

Still, diet is just one component of optimal metabolic health. You can further support your cells by getting adequate sleep, minimizing stress, and exercising regularly.

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Should you track blood sugar?

Traditionally, only people with diabetes tracked their blood sugar regularly. But in the past few years, as the many effects of dysregulated blood sugar have become better known, more people without a diagnosed condition have begun using fingerstick kits (available at a drug store) or continuous glucose monitors (CGMs) to see how their blood sugar changes in response to what they eat and do. CGMs, in particular, give you a real-time view of your individual glycemic variability and, when paired with an app like Levels, helps you find the changes you can make for more stable glucose and better metabolic health.