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Why You Need To Keep Blood Sugar Low: A Research-Backed Answer


If you’re plugged into healthy living, you’ve probably heard all the usual noises about blood sugar. High blood sugar is bad. Low blood sugar is good. You need to manage your blood sugar levels. 

These statements get thrown around casually and often without explanation.

You’re here — not for a sound bite — but for a research-backed analysis of why blood sugar matters. You have a question in mind: why should I keep my blood sugar low? — and you want a proper answer.

It won’t be a short answer, but you’re fine with that. When it comes to your health, you’re not interested in shortcuts. You want the full story.

In a sentence, though, maintaining healthy blood sugar levels helps you burn fat, maintain energy, control appetite, produce ketones, boost brain function, and — most importantly — reduce the risk of chronic disease.

That’s right: high blood sugar doesn’t just put you into fat-storage mode — it also puts you into insulin resistance, or chronic disease, mode.

Fortunately, blood sugar levels are largely driven by lifestyle. Going keto, for instance, can have profound effects on this metric.

You’ll learn about that in a bit. But first, here are today’s topics:

And now in the spirit of understanding, a brief review of blood sugar basics.

What Is Blood Sugar?

You’ve heard of photosynthesis. It’s how plants turn sunlight into energy.

That energy, in fact, is glucose — a simple sugar with the molecular formula C6H12O6. Glucose is merely stored plant energy. Another word for this is carbohydrate.

Glucose is also energy for animals, including humans. Like plants, humans can make glucose. But unlike plants, humans eat glucose. And plenty of it.

Yes: people love their carbs, glucose included. That loaf of bread, that sweet potato, that rice pudding — all of them vessels for glucose.

So how does glucose become blood glucose or blood sugar? Glad you asked.

When you eat a meal — especially a high carb meal — the nutrients from that meal are absorbed, via your intestines, into your bloodstream. Glucose is one of those nutrients.

Simply put: your blood sugar rises when you digest food.

Next, depending on several factors, that blood sugar can be:

  1. Converted to pyruvate, a molecule used to make the cellular energy currencies ATP and ADP. This is called glycolysis[*].
  2. Stored in muscle or liver cells as glycogen.
  3. Stored as fat.
  4. Left in the blood.

You generally want to avoid doors number three and four — and soon you’ll learn how.

Carb intake, however, is not the only factor affecting your blood sugar levels.

What Raises And Lowers Blood Sugar?

Here are the main factors that boost your blood sugar:

3 Factors That Raise Blood Sugar

#1: High carbohydrate intake

Of all the macronutrients, carbs spike your blood sugar the most.

That’s because carbs are sugar — and that sugar enters your bloodstream as soon as it’s digested. It’s been shown, in fact, that a high carbohydrate diet raises blood sugar significantly more than a high fat diet[*].

But high carbs are not the only problem. Even moderate carbs, the research shows, can negatively impact blood sugar levels[*].

Protein also raises blood sugar, but in this regard: not all protein is created equal.

Collagen protein, for instance, has been shown to improve the blood sugar response in type 2 diabetics[*].

#2: Stress

When a caveman got spooked by a dangerous beast, a hormonal response would kick in.

His adrenal gland would release the hormone cortisol, then cortisol would signal the release of glycogen, or stored glucose, from his liver[*]. Then he’d have the energy — in the form of blood sugar — to run or fight.

These days, you’ll probably never encounter a hungry predator, but your stress response still works like gangbusters.

It’s true: everyday chronic stress — from sitting in traffic to arguing politics — contributes to chronic elevations in blood sugar.

#3: Natural Circadian Rhythms

Recall that cortisol — your stress hormone — signals your liver to dump glucose into your bloodstream. But cortisol is not just a stress hormone. It’s also a get-up-and-go-hormone.

Because of this, cortisol levels — if things are working right — are high in the morning and low at night. Cortisol wakes you up in the morning. Just know that higher blood sugar may come along for the ride.

Now on to what lowers blood sugar.

6 Factors That Lower Blood Sugar

#1: Carb Restriction

The simplest way to lower blood sugar? Don’t eat sugar.

Don’t worry: your body has a backup energy molecule to glucose. It’s called a ketone.

#2: Ketogenic Diet

When your restrict carbs, your body starts producing ketones to meet your energetic needs. Ketones, like glucose, can be made into ATP[*].

Simply put: on a high fat ketogenic diet, your body naturally adjusts to lower blood sugar levels.

#3: Exogenous Ketones

Ketones also lower blood sugar directly. Ingesting exogenous ketones, for instance, has been shown to lower blood sugar — even in the presence of carbs[*]. Most people don’t mind the taste of ketone salts, but the same can’t be said of ketone esters.

#4: Intermittent Fasting

Fasting for 12-24 hours every day, it’s clear, has metabolic benefits, including fat loss, disease prevention, and better mental performance.

Another one of these benefits is lower blood sugar levels. Fasting can also increase ketones, which as you just learned above, also reduces blood sugar. This has been shown, to name one example, in men fasting for the religious holiday Ramadan[*].

#5: Calorie Restriction

Eating less calories has been shown to lower blood sugar levels[*] — most likely due to carb restriction. Long term calorie restriction, however, can negatively impact bone density and muscle mass[*].

#6: Meditation

Remember cortisol? It’s your stress hormone. That means keeping stress down also helps keep blood sugar down.

Meditation is a research-backed tool to lower cortisol and improve overall mental well-being.

Researchers recently showed that six months of meditation lowered blood glucose and insulin levels in people with coronary artery disease[*].

You just learned how cortisol affects blood sugar levels. Another hormone, however, is even more important than cortisol for blood sugar regulation. This hormone tells your cells exactly what to do with that pesky glucose: insulin.

Insulin: Your Blood Sugar Boss

Insulin is a hormone secreted by beta cells in the pancreas. What signals the pancreas to secrete insulin? High blood sugar.

To lower that blood sugar, here comes insulin — your blood sugar boss.

Here’s how the boss works.

First, it binds to your cell. Then it activates special transporters — GLUT 4 transporters — on the cell’s surface. Then these transporters haul glucose inside the cell[*].

Depending where this happens, this glucose is stored as either:

  1. Glycogen: Your main storage form of glucose, glycogen is found mostly found in your liver and muscle tissue. Glycogen later gets released (via glycogenolysis) as glucose during exercise, times of stress, or a fast[*]. This prevents blood sugar from dropping too low.
  2. Fat: When glycogen stores are full, insulin caches your blood sugar as adipose tissue. That’s right: insulin is a fat-storage hormone.

Tying this together: when insulin is working properly — when you’re insulin sensitive — excess blood sugar is rapidly cleared from your blood and shoved away in cells for storage. Preferably as glycogen.

But insulin doesn’t always work properly.

Insulin Resistance

Insulin is your blood sugar boss. Your blood sugar rises, your pancreas secretes insulin, insulin commands your cells to take up glucose, your blood sugar falls. Simple.

The boss works hard to keep your blood sugar at healthy levels — but like the CEO of a Fortune 500 company, insulin can get overworked. And when insulin gets overworked, it stops being effective.

Now your cells stop listening to the boss, and your blood sugar suffers. Bad news.

This condition is called insulin resistance. Here’s how it develops:

  1. You eat a high carb meal
  2. Your blood sugar rises
  3. Your pancreas releases insulin
  4. Insulin orders your cells to take up glucose
  5. Your blood sugar falls
  6. You eat another high carb meal. And another. And another.
  7. Your blood sugar rises again and again
  8. Your pancreas spews out barrels of insulin
  9. Your cells stop listening to the overworked insulin and stop storing excess blood sugar
  10. Your blood sugar becomes chronically elevated (hyperglycemia)
  11. More insulin is released (hyperinsulinemia) — which promotes fat storage
  12. Steps 6-11 repeat until obesity, diabetes, or chronic disease develops

As you can see, insulin resistance starts with carb binging. Fix that, and you often fix the problem.

More on that fix soon. First, however, a brief review of the health conditions associated with insulin resistance and hyperglycemia.

High Blood Sugar And Chronic Disease

Type 1 diabetics don’t make enough insulin. That’s why they need intranasal or injectable insulin to regulate their blood sugar levels.

Type 2 diabetics, on other hand, are insulin resistant. Very insulin resistant. And unlike type 1 diabetes, type 2 diabetes is — in large part — a lifestyle disease.

High carb diets create insulin resistance, which often develops into full blown diabetes.

Thanks to insulin resistance, type 2 diabetics suffer a slew of metabolic problems including:

  • Obesity
  • Hyperglycemia
  • Hyperinsulinemia

Unfortunately, the insulin resistance disease parade doesn’t stop with diabetes. Obesity, hyperglycemia, and hyperinsulinemia also increase your risk for the big three:

#1: Cancer

Insulin not only regulates blood sugar, but also cellular growth and proliferation. Insulin is a growth factor — telling your tissues to grow, repair, and store energy.

Unfortunately, insulin also tells cancer cells to grow — possibly by boosting a growth factor called IGF-1. Because of this, researchers have been exploring the link between insulin resistance and cancer[*].

#2: Heart Disease

Everything about diabetes — obesity, hyperglycemia, hyperinsulinemia — increases the risk for heart issues. Researchers have suggested, in fact, that high blood sugar is often to blame for cardiovascular complications in insulin resistant individuals[*].

The most common cause of death for type 2 diabetics? Heart disease.

#3: Neurodegenerative Disease

As if it weren’t busy enough with blood sugar, insulin also helps regulate — among other cognitive functions — your memory.

Unfortunately, like liver and muscle cells, brain cells can become insulin resistant too.

In fact, Alzheimer’s disease — a form of dementia affecting some 5 million Americans[*] — has been linked to insulin resistance in the brain[*].

By now it should be clear: maintaining healthy blood sugar levels should be part of any disease prevention program. So where should the program start?

Easy. With less carbs.

How To Keep Blood Sugar Levels Low: Eat Fewer Carbs

The simplest way to lower blood sugar is to eat fewer carbs. Fewer carbs, lower blood sugar.

Less insulin too. Your insulin response is a function of your carbohydrate intake. Fewer carbs, lower blood sugar, less insulin.

And when you lower insulin — a fat storage hormone — you also store less fat.

Low insulin tells your fat cells to break apart into free fatty acids — a process called lipolysis.

Once released into your blood, free fatty acids yearn to be burned.

This is your body saying: hey, my blood sugar is getting low, I need start burning fat for energy.

Fatty acids, however, aren’t converted directly to energy. First they need to become BHB (beta hydroxybutyrate) or acetoacetate.

In other words, they need to become ketones. Ketones then go through the Krebs cycle to form ATP — or usable energy for your cells[*].

Think of ketones as your fat-powered alternative to glucose. When you enter ketosis: instead of relying on carbs for energy, you now rely on fat.

Good news if you’re trying to burn fat, lose weight, and keep your blood sugar down.

Can Blood Sugar Go Too Low On Keto?

When you restrict carbs, your blood sugar levels go down. And when your blood sugar levels go down, your ketone levels go up.

If your blood sugar dropped to 0 mg/dl, however, you wouldn’t be around to learn about blood sugar anymore. You need some glucose in your blood to survive.

Along with too little glucose, you also don’t want too many ketones. In fact, if your ketone production were to skyrocket — ketoacidosis territory — that would spell disaster.

Fortunately, your body has mechanisms to prevent these things from happening:

1) Gluconeogenesis: No matter how many carbs you restrict or how many ketones you produce — your blood sugar never drops to 0 mg/dl. That’s because you can create your own glucose — usually in the liver — through a process called gluconeogenesis.

Gluconeogenesis keeps your blood sugar from dropping to dangerous, hypoglycemic levels during an extended fast or long period of carb restriction.

2) Glycogenolysis: When your blood sugar drops — during a fast, carb restriction, or intense exercise — your liver and muscle cells release glycogen to restore your blood sugar to normal levels. Glycogenolysis, in other words, helps keep enough glucose in your blood.

3) Inhibition Of Lipolysis: When your blood becomes oversaturated with ketones, this sends the signal to your body: okay, enough ketones, stop breaking apart fat. Without this mechanism, you’d keep producing ketones until a dangerous condition called ketoacidosis sets in[*]. (Note: inhibition of lipolysis is broken in type 1 diabetics, and they must be careful to avoid low blood sugar levels).

Bottom line? Your blood sugar might get low, even borderline hypoglycemic, on a ketogenic diet — but it’s typically nothing to worry about.

In fact, it’s desirable. Lower blood sugar, more ketones, more free fatty acids, more fat burning, more energy. All thanks to skipping that big bowl of glucose.

4 Benefits Of Lowering Blood Glucose

The best argument for managing blood sugar? Probably the disease-risk argument.

Again: high blood sugar and insulin resistance are linked to every major disease, from cancer to Alzheimer’s to heart disease.

If you aren’t managing your risk for these diseases, you aren’t managing your health.

Ketosis can be part of this management program — because when you dial down your blood sugar, you dial up your ketones.

To review: low blood sugar equals low insulin, and low insulin equals ketone production. Then you enter ketosis.

To stay keto, though, you need to keep a watchful eye on your blood sugar. If you feast on carbs, for instance, the resulting hyperglycemia and hyperinsulinemia will kick you out of ketosis. Not cool.

But once you enter a low-insulin, low-glucose ketogenic state — the benefits really start to kick in, including:

#1: Enhanced Fat Burning

If you heard that keto can help you lose weight, you heard right. In fact, the ketogenic diet has been shown — in study after study — to stimulate weight loss[*].

This is partly due to increased fat burning. Blood glucose is scarce on the ketogenic diet — and when blood glucose is scarce, your fat cells get burned to form ketones.

#2: Hunger Management

Appetite regulation also contributes to keto-induced weight loss[*]. Eating a low carb ketogenic diet:

  • Lowers ghrelin, your hunger hormone
  • Lowers neuropeptide Y, a brain-based appetite stimulant
  • Increases CCK, a satiating peptide
  • Prevents spikes and crashes in blood sugar

That last one is crucial. When you ride the blood sugar rollercoaster, you climb high — yes — but you also fall far. And when you crash, you get hungry for more sugar.

#3: Energy Levels

Another danger of riding the blood sugar roller coaster? Energy highs and energy lows. If you’ve ever eaten a whole bag of candy, you’re well acquainted with this devastating energy flux.

Better to have a stable source of energy and get off the coaster for good. Ketones, anyone?

#4: Brain Function

Sugar doesn’t only activate fat-storage mode. It also deactivates your brain.

It’s true: glucose can harm your cognitive function. A published example now.

Researchers fed 49 people either sugar or placebo, then measured cognitive performance with math, response time, and Stroop interference tests. Results? The sugar groups — the groups drinking sucrose or glucose — fared significantly worse than the placebo group[*].

What’s going on here? Too much glucose in the brain.

Ketones, on the other hand, appear to have the opposite effect. They boost brain function. For instance: ketone-fed rats are better maze-navigators, and children show improved cognitive function on the ketogenic diet[*][*].

Yet another reason to cut carbs.

Why Keep Blood Sugar Low?

By now you get it: blood sugar levels matter and you optimize this response by skipping carbs.

Here’s a brief recap of what you learned today:

  • Glucose is a carbohydrate made by plants and eaten by animals.
  • What makes your blood sugar rise: carbs and stress.
  • What makes your blood sugar fall: carb restriction, ketones, and properly functioning insulin.
  • A high carb diet leads to insulin resistance and increases chronic disease risk.
  • Restricting carbs gets you burning fat, which turns into ketones.
  • Ketones lower your blood sugar, but gluconeogenesis — making your own glucose internally — keeps it from falling too low.
  • Preventing high blood sugar reduces disease risk and helps you stay in ketosis.
  • A low blood sugar, ketogenic state enhances fat burning, hunger management, energy levels, and brain function.

Seems simple when you put it in seven bullets, doesn’t it?

Start Lowering Your Blood Sugar

Everyone talks about blood sugar, but nobody explains why it matters. No problem, because now you know.

Here’s how to apply what you just learned to improve your health today: 

#1: Assess Your Carb Intake

You can start by taking a look at your daily carb intake. Is it too high? What meals and snacks are raising your blood sugar the most?

You can track spikes in blood sugar after every meal with a blood glucose monitor.

If you’re constantly having energy crashes, get hungry every 2 hours, get bloated after eating, and usually feel hangry, chances are you’re having too many carbs.

#2: Make Swaps

After you become aware of how many carbs you’re eating per day, it’s time to make changes.

What can you trade in for carbs?

Instead of having sugary cereal for breakfast, make eggs and bacon. Instead of getting a side of rice, get a side salad. Buy better snacks.

Reducing your intake of carbs in every meal or snack you have will make a dramatic difference at the end of the day in terms of your mood and energy levels.

#3: Track Your Health Improvements

When you make these changes, track how they make you feel.

Lowering carbs can give you some immediate perks, such as less bloating after a meal, fewer energy crashes, more stable blood sugar and more satiety if you swap out carbs with protein or fat.

#4: Speed It Up: Go Keto

Going low carb can provide some health improvements, but you’ll reap the most benefits when you go keto. Why?

Because even if you lower your carb intake a little bit, you’re still running on glucose. When you restrict your carbs enough for your metabolism to switch from glucose to fat (ketosis), you’ll start to run on ketones and feel more energetic, burn fat faster, and feel more mentally sharp.

Keep Blood Sugar Levels Low

Keeping blood sugar low will help you live a healthier life. It will reduce your risk of chronic disease, maintain your energy levels, enhance your brain function, and support fat burning.

Having chronically high blood sugar leads to insulin resistance, which can then lead to obesity, heart disease, neurodegenerative disease, and cancer.

The best way to manage your blood sugar levels is to reduce your carb consumption, which is easier than you think.

You can start out my being mindful of how many carbs you’re eating, make low carb swaps, and follow a ketogenic diet to get faster results.

Once you feel the difference between constant high blood sugar and low blood sugar levels, you’ll realize how much healthier and energetic you are eating low carb.


6 thoughts on “Why You Need To Keep Blood Sugar Low: A Research-Backed Answer

  1. I wish I could have you coach me. I’m in my 3rd month of Keto. Still finding my way. Thanks for all your shares. Your writing is so succinct.

  2. thank you, have been suffering from chronic fatigue for 4 years and 50yrs of migraines, and hit rock bottom with a night of acute pancreatitis. came across this site while looking for answers…and after following this advise for a week…I am feel like I am slowly improving. Haven’t had a headache, my energy is improving and I don’t have cravings for carbs. I hope by following the Keto plan that I will be able to also lower my blood pressure and have more energy. Also the weight I have put on from wrong eating and lack of exercise is just melting away. My dream come true of losing weight and eating my favourite foods.

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