【Still at Risk Even on Low Carbs】The Deep Link Between Insulin and Heart Disease, and Why Hidden Excess Insulin Wears Down Your Heart

“I’m cutting back on carbs, so why aren’t my cholesterol and blood pressure getting any better…?”

Have you ever wondered that?

In fact, your risk of heart disease and arteriosclerosis isn’t determined by “blood sugar” alone.

What recent research has been focusing on is a condition called “hyperinsulinemia (hidden excess insulin)”.

Even if your blood sugar is normal, when insulin stays chronically high, your blood vessels get damaged and your risk of heart disease quietly builds up.

Because it progresses with almost no noticeable symptoms, it’s not unusual for blood vessels to be quite damaged by the time you realize it.

In this article, I’ll explain in plain terms how this easily overlooked “hidden excess insulin” wears down your heart, and how to protect your heart by rethinking fasting and your eating habits.

Insulin and Heart Disease: Why Cutting Carbs Doesn’t Lower Your Heart Disease Risk

Blood Sugar Alone Can’t Tell You Your Heart Risk

Many people feel reassured when a health checkup tells them their “blood sugar is normal.”

It’s only natural to think, “If the numbers are within the normal range, I’m fine.”

But to accurately gauge your risk of heart disease and arteriosclerosis, it’s important to check your “insulin level” as well as your blood sugar.

Insulin is a hormone released by the pancreas that lowers blood sugar.

Keep in mind that the hormone itself is essential for life.

Even if your blood sugar is normal, in a state of “hyperinsulinemia,” where large amounts of insulin keep being released, your blood vessels keep taking damage little by little.

That’s why this condition is called “hidden excess insulin.”

Insulin Is the “Delivery Driver” That Carries Blood Sugar

Insulin’s job is easiest to understand if you compare it to a “delivery driver” that brings sugar in the blood to the cells of your muscles, liver, and fat.

If your body can clear the packages with just a little work from the drivers, there’s no problem at all.

But when the cells’ “receiving dock” becomes sluggish, the pancreas sends out many times more drivers to force blood sugar down.

As a result, even though your blood sugar number looks normal, your blood ends up overflowing with delivery drivers.

In other words, the blood sugar test at a health checkup only shows “whether the packages got delivered,” not “how many drivers it took.”

Why Insulin Stays High Even When You Cut Carbs

There’s a reason insulin can run high even when you cut back on carbs.

That reason is “all-day grazing” (a lifestyle of eating all the time without leaving periods of hunger between meals).

Picture a day like this: bread in the morning, coffee and a snack at 10, lunch, an afternoon snack at 3, dinner, and drinks in the evening…

Because insulin’s “shift” never ends all day long, your blood vessels never get time to rest.

It’s not just the amount of carbs, but “how often you eat” that lies at the heart of the insulin problem.

I explain in detail how all-day grazing leads to insulin resistance in
【The Insulin Trap】Why three meals a day make you gain weight, and the pitfalls of snacking and how you eat, so be sure to read it as well.

How Hidden Excess Insulin (Hyperinsulinemia) Wears Down Your Heart

Insulin Directly Damages the Walls of Your Blood Vessels

Insulin doesn’t just regulate blood sugar; it also acts as a “growth factor” that promotes cell growth.

Think of a growth factor as a signal that tells cells, “Multiply more.”

When insulin is chronically high, the inner walls of the blood vessels (endothelial cells) are overstimulated, causing inflammation and proliferation.

As a result, the inside of the blood vessels thickens (intimal thickening), and arteriosclerosis speeds up.

To compare it to a water pipe, it’s like grime gradually building up on the inside, making the passage for water narrower and narrower.

Some researchers point out that a high-insulin state may cause arteriosclerosis even faster than cholesterol does.

It Raises Triglycerides and Lowers “Good” HDL Cholesterol

When insulin is high, the liver tries to store extra energy as neutral fat (triglycerides).

Triglycerides are like a “spare gas tank” packed with energy you couldn’t use up.

When triglycerides in the blood increase, good cholesterol (HDL) decreases, and small, dense “bad” LDL increases.

The troublesome part is that small LDL particles, being so small, are said to slip more easily into gaps in the blood vessel walls.

This combination of “high triglycerides and low HDL” is considered one of the strongest risk factors for heart disease.

If you have your health checkup results on hand, look at your triglyceride and HDL numbers side by side.

If your triglycerides are high and your HDL is low, it may be a sign that a high-insulin state is hiding beneath the surface.

The “Vicious Cycle” Created by Visceral Fat and Insulin

Insulin also works to store leftover energy as fat.

The longer insulin stays high, the more easily fat builds up around the organs in your abdomen.

Visceral fat isn’t just “stored energy”; it’s thought to be an active tissue that releases substances that cause inflammation.

Those inflammatory substances make the cells’ “receiving dock” even more sluggish, creating a vicious cycle in which insulin rises yet again.

Inside this loop, your blood vessels and heart keep getting damaged little by little, so the cycle has to be broken somewhere.

The Risk of a “Chronic High-Insulin State,” Which Is Scarier Than After-Meal Blood Sugar

The Problem of “Fasting Insulin,” Which Health Checkups Miss

Standard health checkups in Japan measure blood sugar and HbA1c (hemoglobin A1c), but in most cases they don’t measure insulin levels.

As a result, “hyperinsulinemia,” where insulin is chronically high even though blood sugar is normal, gets missed.

It’s like looking only at the speedometer and declaring “nothing wrong” while the engine is racing.

Multiple studies have shown that people with high fasting insulin levels (generally 10 μIU/mL or higher) have a significantly higher risk of heart disease.

If you’re concerned, it’s worth asking your regular doctor for a “fasting insulin test.”

The Long-Term Damage Insulin Resistance Does to the Heart

As insulin resistance (a state in which cells respond poorly to insulin) progresses, the pancreas starts releasing even more insulin.

This makes the “chronic high-insulin state” more serious, and the strain on the heart piles up.

Because it also causes higher blood pressure, salt retention by the kidneys, and overactivity of the sympathetic nervous system, hyperinsulinemia can be called a “silent killer” that damages the heart, kidneys, and blood vessels all at once.

The sympathetic nervous system is the body’s “accelerator,” and if it stays pressed down, your heart ends up working nonstop with no time to rest.

For more on how insulin resistance progresses, also read 【Watch Out If You’re Prediabetic⚠️】The frightening way insulin resistance progresses even without symptoms.

What surprised me most when I started fasting was that my blood pressure and weight went down at the same time.

I never imagined my body could change this much just by eating less often and letting insulin rest.

Suspect Hyperinsulinemia If This Sounds Like You

Even if you’ve never had your insulin measured, be careful if several of the following traits apply to you.

The more items that apply, the more likely it is that insulin is working too hard inside your body.

If even one of them concerns you, it’s a good idea to talk to a doctor without waiting for your next health checkup.

Surprising Eating Habits and Pitfalls That Cause Hidden Excess Insulin

The Trap of Foods That Look “Healthy” but Raise Insulin

There are cases where foods labeled “low-fat” or “sugar-free” are actually causing a high-insulin state.

Because all of these have a “seems good for you” image, they’re exactly the kinds of foods you tend to reach for often.

Remember that what matters isn’t giving these foods up completely, but not grazing on them as snacks throughout the day.

If you do eat them, just grouping them into mealtimes and deciding on an amount ahead of time can make a big difference in the burden on insulin.

“How Often and When” You Eat Shapes Insulin Just as Much as “What” You Eat

When and how many times you eat affects insulin just as much as whether you eat carbs, fat, or protein.

In other words, even with the same menu, your body’s response can change greatly depending on how you eat.

Late-night meals are especially problematic.

At night, your metabolism slows and insulin sensitivity drops, so the same meal causes a higher insulin response than it would during the day.

A lifestyle of coming home from work, eating dinner at 10 p.m., and going straight to bed can mean spending the whole night with high insulin.

I also recommend writing down the times of your meals and snacks on a typical weekday.

Many people will probably notice that the time they spend “putting something in their mouth” is longer than they thought.

The trick is to count a drink with sugar or milk in it as one “meal” too and write it down.

For the chain linking metabolic syndrome and heart disease risk, also see 【Obesity Is the Gateway to Disease】The relationship between metabolic syndrome and diabetes, and the chain of diseases that starts with visceral fat.

Stress and Lack of Sleep Also Push Insulin Up

Even if you’re careful about what you eat, you can’t let your guard down, because ongoing intense stress or lack of sleep tends to raise insulin.

That’s because under stress, your body releases hormones that raise blood sugar to “prepare for a fight.”

And then insulin gets called in again to bring that raised blood sugar back down.

It’s said that this mechanism is also related to why you tend to crave sweets and carbs the day after a string of short nights.

Along with rethinking your diet, going to bed and getting up at the same time every day is also an important habit for protecting your heart.

Tests and Precautions for Lowering Insulin and Protecting Your Heart

Tests You Can Get at a Medical Facility

If you’re concerned about hyperinsulinemia, ask a medical facility about tests like the following.

Which tests you need differs from person to person, so the surest approach is to tell your doctor which numbers concern you and let them choose.

Look at the “Trend,” Not a “Single” Number

Test numbers can change depending on how you feel that day or what you ate the day before.

Rather than getting excited or discouraged over a single result, lining up the changes every six months or year makes it easier to see the true state of your body.

If your triglycerides, waist size, and blood pressure are gradually creeping up, it may be a signal that the time insulin stays high is getting longer.

On the other hand, if these numbers come down after you start eating less often, it’s a sign that your efforts are paying off.

Don’t throw away your health checkup results; keep them together in a file and bring them to your appointments so the conversation goes smoothly.

If You Take Medication, Always Consult Your Doctor Before Fasting

If you use oral diabetes medication or insulin injections, avoid skipping meals on your own judgment.

That’s because if the medication works as usual while you eat less, there’s a risk of “hypoglycemia,” where blood sugar drops too low.

Trembling hands, cold sweats, intense hunger, and feeling foggy are signs of hypoglycemia, so take some sugar right away.

If you take medication, always talk to your doctor about your dose before you start fasting or changing how often you eat.

Don’t Ignore an SOS From Your Heart

If you have any of the following symptoms, see a doctor before you start rethinking your diet.

If the chest pain is severe or comes with a cold sweat, don’t hesitate to consider calling an ambulance.

Frequently Asked Questions About Insulin, Heart Disease, and Hidden Excess Insulin

Protect Your Heart From Hidden Excess Insulin! Start Improving Today With Fasting and Better Eating Habits

Here’s a summary of what you can do starting today to protect your heart from hidden excess insulin.

If jumping straight to 16 hours is hard, start by cutting out snacks and leaving 12 hours between dinner and the next morning.

It’s easier to keep going if you take it one step at a time, for example focusing only on “cutting out snacks” in the first week, then pushing breakfast back a little from the second week.

During your fasting window, stay hydrated with frequent sips of calorie-free drinks such as water, tea, or black coffee.

Noting not only your weight but also your blood pressure and waist size once a week should make it easier to see changes in your heart and blood vessels.

“When and how many times you eat” is just as much the key to insulin and heart health as “what you eat.”

For the specifics of how to start fasting and its effects, be sure to check out 【The Complete Beginner’s Guide】Types, benefits, and how to do intermittent fasting.

If you’d like to make fasting easier to stick with, also consider using a supplement that supports fasting.

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