What Should Your Blood Sugar Levels Be?

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If you want to manage your long-term health, it pays to manage your blood sugar levels. Blood sugar is not only associated with diabetes risk, but also the risk of cancer, dementia, and many other chronic diseases. 

Blood sugar levels govern your day-to-day well-being too. Low energy, headaches, cravings, and irritability all come along with riding the blood sugar rollercoaster. 

Getting off the coaster means keeping blood sugar levels within stable, healthy ranges. So, what are these ranges, and how can you maintain them? We’ll answer these questions shortly. First, though, let’s cover some basics.

What Is Blood Sugar? 

Blood sugar (blood glucose) refers to the quantity of glucose circulating in your blood. It’s the primary marker doctors use to assess diabetes risk. 

Glucose is a monosaccharide (simple sugar) with the molecular formula C6H12O6. Plants create glucose via photosynthesis; when you chow down on those plants, the sugar arrives in your bloodstream to provide energy. 

To make that energy, you convert glucose (via glycolysis) into pyruvate, which then converts to ATP and NAD+. ATP and NAD+ are energy currencies for all living cells and not optional “nice-to-have” molecules. And so, if blood sugar gets too low (hypoglycemia), it causes a life-threatening energy crisis. 

Food isn’t your only source of glucose. Since glucose is essential to survival, we’ve evolved these glucose backup systems:

1. Gluconeogenesis: the formation of glucose in the liver from compounds like lactate. 
2. Glycogenolysis: the release of glycogen (stored glucose) from liver and muscle cells. 

Let’s discuss glucose regulation now. 

Blood Sugar and Metabolic Health 

Metabolic health refers to how your body uses, stores, and partitions energy. Maintaining metabolic health is correlated directly with overall health. One doesn’t come without the other. 

When metabolic health is good, the hormone insulin effectively keeps blood sugar within healthy ranges. You eat carbohydrates, blood sugar rises, your pancreas releases insulin, insulin directs blood sugar into the muscle and liver cells for safe storage, and blood sugar and insulin levels fall.

When metabolic health is bad, insulin is unable to function effectively. Blood sugar stays elevated, insulin stays elevated, and you get stuck in energy-storage (fat-storage) mode. This unfortunate condition called insulin resistance is the basis of type 2 diabetes.

Type 2 diabetes is a label for a barrel of metabolic problems. These problems manifest as high blood sugar, high insulin, high triglycerides, obesity, and higher risks of death and chronic disease. Improving type 2 diabetes (and metabolic health in general) means improving blood sugar levels. Let’s discuss how to monitor that. 

How to Measure Blood Sugar 

There are four main tests to measure blood sugar levels:

1. Fasting Blood Glucose (FBG): Blood sugar levels following at least twelve hours of fasting. 
2. Postprandial Blood Glucose (PPBG): Blood sugar levels an hour or two after eating.
3. Hemoglobin A1c (HbA1c): Average blood sugar in red blood cells. (HbA1c assumes blood cells live for three months, but since cellular lifespans vary between people, it’s not a perfect test.)
4. Oral glucose tolerance test (OGTT): Blood sugar levels two hours after drinking 75 grams of liquid glucose. 

Tests one and two use a simple finger-prick device. You can also do an at-home HbA1c test, but you’ll need to visit a lab for the OGTT. 

For more comprehensive tracking, you might consider a continuous glucose monitor (CGM.) With a CGM, you can track your blood sugar response to different foods, sleep amounts, exercise, emailing a disgruntled colleague, etc. Understand, however, that a prescription is necessary for this device. If you do not have a diabetes diagnosis, you can contact a company like Tastermonial that offers CGM prescriptions for non-diabetic individuals. The alternative is paying out of pocket (which could cost over $1,000 annually). 

What Should Your Blood Sugar Levels Be? 

Let’s start with how the American Diabetes Association (ADA) classifies diabetes risk for diagnostic purposes:

• Normal: FBG below 100 mg/dl, HbA1c below 5.7%
• Prediabetes: FBG between 100–125 mg/dl, HbA1c between 5.7–6.4% (inclusive)
• Diabetes: FBG above 125 mg/dl, HbA1c above 6.4% 

Fasting glucose under 100 mg/dl is considered “normal,” but is normal synonymous with optimal? 

Probably not. In a large observational study following 46,578 people over 81 months, fasting glucose levels between 95-99 mg/dl correlated with a 2.33 times higher risk of developing diabetes than levels below 85 mg/dl.

A similar story applies to HbA1c. One study following over 4,000 people for 3.5 years found that normal HbA1c levels between 5.4–5.6% correlated to higher heart disease risk than levels below 5%. Again, normal wasn’t optimal. 

Now, let’s turn to postprandial blood sugar because research suggests it’s a better predictor of heart issues than fasting blood glucose. The literature also suggests that targeting post-meal glucose spikes reduces the risk of type 2 diabetes, heart disease, and other chronic conditions.

Published reference ranges recommend keeping PPBG below 140 mg/dl for people without diabetes and below 180 mg/dl for people with diabetes. Lower is better, however, so these limits should be considered upper bounds. Additionally, women with type 2 diabetes who had a cardiovascular event (within five years) had an average post-lunch glucose of over 200 mg/dl, while women without an event had an average PPBG close to 150 mg/dl.

The takeaway? Aim to keep fasting blood glucose south of 85 mg/dl, HbA1c under 5%, and postprandial spikes as small as possible. 

5 Tips for Healthy Blood Sugar Levels 

Let’s get practical now with diet and lifestyle tips to manage blood sugar levels. 

#1: Limit processed carbs 

Processed carbs like sugar, bread, pasta, white rice, cookies, and bagels elevate blood sugar levels rapidly and significantly. Limiting these foods is step one in any blood sugar management program. 

#2: Consider low-carb or keto

Along these lines, low-carb and ketogenic diets can effectively reduce blood sugar levels. In one study, a year of supervised keto dieting reversed type 2 diabetes (measured by HbA1c) in 60% of 218 patients. 

#3: Sleep well 

Sleeping 7–9 hours per night supports insulin function for healthier blood sugar levels. Good sleep also stabilizes hunger hormones so you don’t continually crave snacks.

#4: Exercise

All forms of exercise activate GLUT4 receptors in muscle cells that suck up glucose like a dog gobbles up fallen leftovers. High-intensity interval training (HIIT) may have the largest effect, just three 15-minute sessions per week have been shown to improve insulin sensitivity in older adults.

#5: Use blood sugar-lowering compounds 

Many drugs, supplements, and foods can support healthy blood sugar, including:

• Spices like cinnamon and turmeric
• Supplements like berberine and bitter melon
• Amino acids combined with chromium

Let’s double-click on the last bullet. When people consumed a drink containing leucine, threonine, lysine, isoleucine, valine, and chromium picolinate with a meal, their postprandial blood sugar dropped by an average of 25%.

These randomized controlled trials illustrate the science behind GOOD IDEA. The amino acids prime the metabolism to reduce blood sugar spikes, while chromium enhances insulin function to bring glucose into cells. This unique synergy helps to stabilize blood sugar levels with zero sugar or caffeine. 

And so, GOOD IDEA complements a holistic metabolic strategy that includes exercise, sleep, stress management, and limiting refined carbs. Dial in these areas, and you’ll be on your way to dialing in your metabolic health. 

Author: Brian Stanton is the author of Keto Intermittent Fasting and a leading authority on health and nutrition. Follow Brian’s work by visiting his website at www.brianjstanton.com.