top of page

Blood Sugar

Our body breaks down every carb we ingest into glucose, also known as blood sugar because it travels through our bloodstream. Glucose is a simple sugar — more precisely, a monosaccharide (mono meaning single and saccharide meaning sugar).

To store glucose, your body combines the molecules into a polysaccharide (poly meaning several) called glycogen, which gets stored in our liver and muscles.

Insulin (a hormone produced by our pancreas) rises when blood glucose rises; it lowers blood sugar by telling various cells to absorb it — for storage in our liver or muscles or for immediate use — and our liver to stop producing new glucose.

The ability of cells to absorb glucose in response to insulin is called insulin sensitivity, and low insulin sensitivity is called insulin resistance. The more sensitive we are to insulin, the less resistant, and vice versa.

It is also possible to produce too little insulin. If we have type 1 diabetes or are in the late stages of type 2 diabetes, in which case we suffer from insulin deficiency, glucose can’t be removed efficiently from our blood, causing hyperglycemia (overly high glucose levels).

Insulin resistance paves the way for type 2 diabetes, which can cause our blood sugar levels to consistently remain too high for too long. If not managed, these high blood sugar levels can lead to serious health complications — mostly cardiovascular diseases, but probably cancer, Alzheimer’s, and Parkinson’s as well.

How are blood glucose levels assessed?

Glycemic control can be tested several ways, each with its own cutoff values indicating impaired glucose regulation. Of these tests, fasting blood glucose is the most common, followed by hemoglobin A1C (HbA1c).

Fasting Plasma Glucose

Fasting plasma glucose (FPG), also known as fasting blood glucose, is simply a measure of how much glucose is floating around in your blood during a fast. After at least 8 hours of not eating (typically in the morning, before breakfast), blood is drawn and analyzed for glucose concentration.

Interpreting FPG results


<5.6 (mmol/L)


5.6–7.0 (mmol/L)


>7.0 (mmol/L)

Hemoglobin A1c

Hemoglobin A1c (HbA1c), or glycated hemoglobin, is a marker of blood-glucose metabolism that estimates the average amount of glucose in your blood over the past 3 months.

The protein that carries oxygen throughout your body, called hemoglobin, is in red blood cells, which live for about 4 months. Glycation is when a sugar — in this case, glucose — is linked to a protein or lipid — in this case, hemoglobin. When blood glucose levels rise, the rate of hemoglobin glycation increases, making glycated hemoglobin an estimate of blood glucose levels over months.

Interpreting HbA1c results


<5.7 (mmol/L)


5.7–6.4 (mmol/L)


≥6.5 (mmol/L)

What are the symptoms of abnormal blood glucose levels?

Symptoms of abnormal glucose levels are different from person to person and may not even be present until the levels are very high or very low. Generally, blood sugar symptoms may show up when levels fall below (3.9 mmol/L) or over (10 mmol/L).

Symptoms of high and low blood glucose


Anxiety Blurred vision Changes in behavior or personality Clammy skin Confusion Difficulty speaking Disorientation Dizziness or lightheadedness Fast or irregular heartbeat Fatigue Feeling shaky or jittery Headache Hunger Lacking coordination Nausea Seizure Sleepiness Sweating Weakness


Blurry vision Dry mouth Dry skin Fatigue Frequent urination Fruity breath odor Increased thirst Nausea and vomiting Rapid heartbeat Shortness of breath Stomach pain

What affects blood glucose

Diets & foods

Across numerous observational studies, grains, vegetables, fruits, and dairy have been consistently associated with decreasing the risk of type 2 diabetes.

Multiple randomized controlled trials (RCTs) have come to similar conclusions.

  • Nuts, grains, legumes, and dairy provided the greatest fasting blood sugar reductions.

  • Grains, legumes, nuts, fish, fruits, and vegetables improved HOMA-IR (a measure of insulin sensitivity) the most.

  • Grains, legumes, fruits, vegetables, and nuts provided the greatest blood sugar reductions in HbA1c tests.

Listed from most to less potent, grains, nuts, legumes, fruits, and vegetables had the greatest impact on improving overall blood sugar control.


The major cause of abnormally high blood glucose is excess calorie intake and the resulting increase in fat mass. Unsurprisingly, weight loss can help. One review found that weight loss from all kinds of interventions — surgery, appetite-suppressing medicines, lifestyle interventions, or a combination — alleviates diabetes.

Surprisingly, many long-term studies that used diet alone to achieve weight loss reported only modest improvements in diabetes, probably because few achieved substantial long-term weight loss. Moreover, exercise in itself can help reduce the risk and severity of type 2 diabetes.

Exercising regularly and maintaining a healthy weight are the two major pillars of metabolic health, but insulin resistance can be complex. As a result, the basics may not always cut it, and what’s effective for one person may not be for another.

Unfortunately, researchers are often unable to explore differences between individuals, leaving diabetics to fight their disease through trial and error based on what’s effective for the majority.

Medical conditions & considerations

Stress, illness, physical trauma, and dehydration can do some strange things to your blood sugar levels. Menstrual cycles and pregnancy may also throw off your blood sugar.

Injury to the pancreas, where insulin is produced, can lead to hyperglycemia, as can hormone disorders such as Cushing’s syndrome (excess cortisol in the body), pheochromocytoma (a usually benign tumor in an adrenal gland), hyperthyroidism (high thyroid levels), and acromegaly (excess growth hormone that causes abnormally large features).

The information above was taken from members information. - Examine is the largest database of nutrition and supplement research on the Internet. Founded in early 2011, their mission is to analyze the full body of evidence to help us make healthy choices. As an educational organization, they are not affiliated with any supplement or food company, nor are any members of the research team.

11 views0 comments

Recent Posts

See All


bottom of page