Glucose

Why it matters

Glucose is your body's main fuel. Every cell can burn it, and your brain runs on almost nothing else, so you need a steady supply in your blood. The health question is not whether you have glucose, but how well your body manages it.

That management job belongs to insulin, and it is where metabolic health is won or lost. Glucose is the number you can see. Insulin is the one doing the work behind it.

What causes spikes

A spike is a fast, steep rise in blood glucose after eating. Refined carbohydrates and sugar cause the sharpest ones, because they break down and flood the bloodstream quickly.

Sugar carries a second problem. Table sugar and high-fructose corn syrup are half fructose, which the liver handles almost alone. Send it more than it can cope with and it turns the excess into liver fat, the first step towards insulin resistance.

Fibre is the natural brake. Whole fruit comes wrapped in it, slowing absorption and keeping the rise gentle. Juice strips the fibre away, so the same fruit becomes a fast sugar hit. Whole fruit is food. Juice is closer to a soft drink.

Glucose and metabolic syndrome

Every spike asks insulin to clear it. Do that often enough, on high sugar and processed food, and insulin stays raised all the time. Chronically high insulin tells the body to store energy as fat, and over time cells stop responding to it. That is insulin resistance, the engine underneath metabolic syndrome.

From there the markers move together: rising blood pressure, higher triglycerides, more fat around the middle, and glucose that no longer settles. This is why glucose does not stand alone. It tracks with the numbers on your other pages. Lustig's bottom line is that the real target is fasting insulin. Keep that low and the rest tends to follow.

Measured before eating. Read from the bottom up.

Watching in real time

A continuous glucose monitor lets you see how your own body answers each meal, the closest thing to watching your metabolism live. The aim is a gentle shape: hills rather than sharp spikes. Notice which foods send you climbing and which keep you steady, and you will learn more about your diet than any label can tell you.