You are here

Essential Notes on Blood Sugar and Insulin


You have approximately 5 liters (about 21 cups) of blood traveling around in your blood vessels and heart at any given moment. In these 5 liters of blood, you need only about one teaspoon of sugar for all of your regular activities. If you regularly have more than a teaspoon of sugar floating through your blood vessels, the excess sugar can slow down your circulation, which, over time, can cause all of the problems you would expect to have if you had thick maple syrup clogging up your blood vessels. This is essentially what happens when a person becomes diabetic.

In order to keep the amount of sugar floating through your blood vessels at around a teaspoon, your body releases insulin whenever you eat foods that release sugar into your bloodstream. Eating sugary foods, most sweeteners, grains, cookies, pastries, cakes, pasta, and starchy vegetables like potatoes all lead to a release of sugar into your bloodstream. Insulin works by stimulating your cells to sponge up this excess sugar out of your bloodstream. Once inside your cells, sugar is used for energy, with any excess amount being converted to fat tissue.

If you regularly eat sugary foods and highly processed carbohydrates, your body will have released so much insulin that it will begin to lose its sensitivity to insulin, which means that your cells won’t receive as strong a signal to sponge up excess sugar out of your blood. This will lead to excess sugar floating around your blood vessels and all the health problems that come with this scenario.

Just a few years ago, 110 - 120 mg/dL (6.1 - 6.7 mmol/L) was widely considered the upper range for a normal fasting blood sugar level. Today, a fasting blood sugar level less than 100 mg/dL (5.6 mmol/L) is considered normal, while anything within 100 to 125 mg/dL (5.6 to 6.9 mmol/L) is considered prediabetes.

With all the blood work that I have looked at since the late 90s, I feel that a healthy fasting blood sugar level should be in the range of 70 - 90 mg/dL (3.9 - 5 mmol/L).

You can get your fasting blood sugar/glucose test done at your doctor’s office, or with a home monitor, performed after at least six hours of fasting. The difference is that laboratories measure sugar in a component of your blood called plasma, while home monitors measure sugar in whole blood. It is believed that home monitors that measure sugar in whole blood give readings that can be around 15 percent less than plasma readings from laboratories. Some home monitors are calibrated to give plasma-equivalent readings. Regardless of what kind of home monitor you might use, it's handy to have an objective way to ensure that your food choices are keeping your fasting blood sugar level close to or in a healthy range.


If you have too much sugar floating around in your blood vessels, it is likely that you also have too much insulin traveling through your system as well. Even if your fasting blood sugar level is in a healthy range, it is possible that you have too much insulin floating through your vessels, particularly if you have high triglycerides and/or are overweight. Normal blood sugar and high blood insulin can be the result of your cells losing some sensitivity to insulin, which necessitates that your body releases extra insulin into your blood circulation to stimulate your desensitized cells into sponging up excess sugar out of your blood circulation.

What's the problem with having too much insulin in your circulation?

Excess insulin is known to cause:

  • Weight gain, since insulin promotes the storage of fat

  • Lower cellular levels of magnesium, a mineral that is essential for keeping your blood vessels relaxed and your blood circulation efficient

  • An increase in sodium retention, which leads to holding excess water in your system, which causes high blood pressure

  • Increased amounts of inflammatory compounds in your blood, which can cause direct physical damage to your blood vessel walls and encourage the development of blood clots which can lead to heart attacks and respiratory failure

  • A reduction in HDL, an increase in undesirable small molecules of LDL, and an increase in triglycerides, all of which increase your risk for heart disease

  • Possibly a higher risk for cancer due to insulin's ability to contribute to cell proliferation

You can test your insulin level by asking your doctor or laboratory for a fasting insulin test. Less than 10 IU/mL is ideal. Anything over 10 IU/mL indicates that you are eating too many foods that are stimulating excess insulin release from your pancreas, paving the way to all of the negative health effects listed above.

What can you do with your food and lifestyle choices to support healthy blood sugar and insulin levels?

  1. Make non-starchy vegetables the foundation of your diet. Dark green leafy lettuce, tomatoes, celery, cucumber, cabbage, kale, Swiss chard, bok choy, zucchini, broccoli, cauliflower, and all unmentioned green vegetables are excellent choices.

  2. Reduce intake of sugar and all foods that contain sugar. Some of the most concentrated sources of sugar are soda, cookies, chocolate bars, donuts, pastries, ice cream, and ketchup.

  3. Reduce use of sweeteners like molasses, corn syrup, high fructose corn syrup, pasteurized/heated honey, and maple syrup.

  4. Reduce intake of fruit juices. Even freshly squeezed fruit juice taken over the long term can lead to high blood sugar and insulin levels. If you want to taste fruit, eat whole fruit, not the juice. The fiber, vitamins, and minerals that come with whole fruit help to slow down the pace at which the natural sugars from fruit enter your bloodstream. And choose fruits that are richly pigmented throughout their flesh over those that are only richly pigmented in their skins. For example, blueberries, raspberries, and blackberries are more nutrient-dense than apples, pears, and bananas.

  5. Do activities and exercises that build or maintain your muscles. Muscle tissue acts as a reservoir for extra sugar. The more muscle tissue you have, the better you can regulate your blood sugar and insulin levels.


Join more than 80,000 readers worldwide who receive Dr. Ben Kim's free newsletter

Receive simple suggestions to measurably improve your health and mobility, plus alerts on specials and giveaways at our catalogue

Please Rate This

Your rating: None Average: 4.5 (341 votes)
This question is for testing whether you are a human visitor and to prevent automated spam submissions.
Enter the characters shown in the image.


For the last couple of months I had been eating mostly fruit, as I had embarked on a "raw food journey" to heal some health ailments. About a week ago I noticed I had VERY frequent urination, and it was always clear (very odd for me), and I was always thirsty. I was also experiencing an irregular heartbeat and palpitations. After doing some research online, I realized I had a MAJOR overload of sugar. For some reason it had not occurred to me that fruit would cause this because "it's natural". So, 5 days ago I went the other extreme (pretty much no sugar, save the small amount in lemons and green vegetables), and I am already feeling much better. I've also added slow-cooked meats and small amounts of raw egg yolk. I'm beginning to wonder if sugar/insulin/candida have been my problems all along and if this one simple measure would have put me on the right path to health. Time will tell! Thanks Dr. Kim for this article. You have a way of making health issues easy to understand.

You better go to your pimary care doctor. Just because you stopped showing symtoms doesn't mean you're not still having sugar problems. Two hrs after a meal your sugar should be below 110. The symptoms you have are diabetes. I know, I had the same symptoms. Went to the doctor, they ran blood tests, results were that I'm diabetic. High sugar levels over a long period will cause permanent nerve damage, and damage to your eyes. That is something you don't want to mess with. Blindness by diabetes is the number 1 cause. Just because you limited sugar intake doesn't mean the problem went away - only your symptoms. Slight elevation of sugar levels will show no symtoms. But it will greatly damage your body and kill you. Get to a doctor now. I have friends that were on fruit diets and the sugar never bothered them, because they were not insulin resistant or had pancreas problems. Get to a doctor if you love your family, only a doctor can help you get it under control

The last thing I would do is go see a "traditional" doctor for diabetes; except for the actual diagnosis.

See "An Orthomolecular Approach to Diabetes" on Youtube.

Dr. Jul
ian Whitaker runs a clinic in California where his success is amazing at reversing diabetes.

Also see the documentary "Simply Raw - Reversing Diabetes in 30 Days".

There are many examples of clinics doing the same thing...just google or youtube "reversing diabetes"

Just my humble opinion,

I have no personal experience with Dr. Whitaker, other than emailing him to ask what the cost was to attend his clinic. He answered that he couldn't give an actual dollar amount because it was different from one patient to the next. He wouldn't even give a ballpark estimate. To me,this was a red flag, and I would not consider going to his clinic. I'd rather go to the Gerson's, who have set costs.

I had the frequent urination and sugar taste constantly after anything sugary. Id have sugar highs and lows (extreme fatigue and weakness). My fasting glucose was 87 but at times has been in the 90s and most nurses and docs look at that as normal. Then I had insulin checked. It was 10.8 so the naturalpathic doc put me on metformin (1000 bid). He says I have some insulin resistance prohibiting me from loosing weight and may help fertility. I have lost 5lbs in two months without trying. I also have fertility problem which can be from other health issues. I don't fit the picture for many docs because I'm 30yrs, 155lb, 5'3. Unless you know my whole history you would think he was crazy. I encourage you to find the right who doesn't fit you into a box and one who listens to your symptoms...not just what you look like. Healthy eating is a great way to avoid medication and restore your bodies balance naturally.

Do you have polycystic ovary syndrome. I do and I have the same as you. Can't lose weight, high insulin, infertility. I see an endocrinologist and she has helped.

I tried to see one of this doctors and they don't diagnose only treat.

I never heard that type of doctor, never heard about insulin level either that they can test that. I have symptoms of low sugar. I will see that type of doctor that you are mentioning. Thanks.

Hi. I am a little confused & am hoping you can explain something to me. I have over the years always had high fasting insulin levels (between 40-45), but my fasting glucose levels have always been under 5.6. That is until about a month ago when my dr had me do a glucose tolerance test. Prior to taking the glucose my reading was 20. After giving me glucose to drink, the reading shot up to 23. My fasting insulin was 40. I have been put on some meds & have been monitoring my glucose levels at home (they ranging between 12.5 - 16.9). Now this is what I don't understand. How can BOTH my insulin & glucose be high?

Great question ...
both levels become elevated once you reach the stage of insulin RESISTANCE, but before you hit insulin DEPENDENT. When your cells are no longer responsive to the elevated amount of insulin in your blood ... that is increased to try to counteract the elevated glucose ... then both ranges will remain elevated.
People that have blood sugar issues that have NOT hit insulin resistance yet will have elevated levels of insulin but can have perfectly normal blood sugar levels because the insulin is still doing its job and driving insulin into the cells and taking it out of the bloodstream.
Hope this makes sense =)

My suggestion ... and many other functional medicine practitioners will recommend that with diet and lifestyle changes, and working with a qualified practitioner, that you can reverse your diabetic state. Medications never reverse diabetes ... but there is hope in eating well, moving more, and possibly addressing some underlying toxicity that can all lead to diabetes.

Believe me, you do not want to become diabetic! Maybe you think its hard to change your diet, but you must. Diabetes is NOT simple or easy and the potential consequences are terrible. I am type 1 taking insulin daily and have been searching for years to find ways to stabilize my BS with great difficulties while raising 4 children and losing my 5th. I now eat High Fat and it so far has worked. My diet has changed a lot, no more carbs, no root veggies, and I eat way more organic meat and fish than I have in years but even protein is limited as i burning fat. Its called ketogenic. Its been a long and trying road for me but i am finally getting things right and ketogenic works for me. I also intermittently fast and juice about 4 to 5 days a week, no fruit and its dark green, really dark green with ginger, tumeric and chilies in it. It doesn't raise my BS and I need only 1 unit of insulin for my juice. I also make cocobomb, recipe by Dr. Mercola, check it out as it's vegan and high in omega 3's. One real positive point on my very green juice, it takes and gets rid of all my phlegm and or mucous as I drink it.

Hi. I've been type 1 for 27 years. Just want to say that beware the high fat diet, I've previously followed a lower carb / higher fat diet and it was good for while but then, I think it happened overtime rather than me just not noticing, the fat causes High Glucose levels. It tends to be worse during the night if I've eaten a higher saturated fat meal in the evening. I'm not sure of the mechanism but the fat basically blocks the insulin and prevents its from working. This tends to happen about 5 to 7 hours after a the meal. Then a correction dose of double the usual units of insulin is required to bring it back down, for me anyway, maybe different for others.
This phenomenon has been studied so you can probably find further details on the web, i think i remember reading on the mayo clinic website about the research after I'd come to my own hypothesis and it fit pretty much exactly what the study reported. I remember some comments from people totally denying that this could happen, probably the paleo crowd where fat fixes all. i say this as someone who tried paleo, ketosis for years btw :)
Best thing I did for my diabetes is to inject my short acting insulin (I take humalog) into my deltoid, as recommended by Richard Bernstein. It's goes straight into the muscle instead of into the fat and it works a lot quicker. The insulin peaks much quicker and follows the profile of the glucose being released by foods much closer. Don't bother if you get your carbs from veg (except root veg). I'm pretty lean and have little fat on my deltoid, so this technique may not work for those with excess fat on their deltoids..
I'm not saying this to scare people off ketogenic diet, if it works then great but if you do start to experience unexplained high glucose readings then think back to how much fat you ate hours before.

This is not bio-chemically possible. Of the macros, carbs and protein require the pancreas to secrete insulin. Fat is the only macro which does not require insulin. The pancreas does not and will not secrete insulin if fat is eaten. Most people who start following a ketogenic eating plan, track carbs (25g/day or 100 calories) and the protein should make up about 15% of calories per day (protein has 4 calories per gram), and the remainder of your daily intake is fat grams, which have 9 calories per gram. If anything, without planning or counting grams, people who start Keto go over on the protein.

I have a question about Dr. Kim's mention that the body requires "only 1 teaspoon (5 grams) of sugar for all of its regular activities." Does this mean 1 teaspoon of sugars in the blood PER DAY, or per meal, or some other time frame? I am an avid nutrition label reader, and I think just knowing this detail about how much sugar the body needs to perform its basic functions --(heavy exercise not included, I presume)--will help me a great deal in motivating me to stay away from random treats that someone brings into the office or similar circumstance. This was just the info-oomph I needed to be more restrictive in food selection for better health (particularly given my adrenal fatigue and kidney deficiency.) Thanks, Dr. Kim, for this and any additional guideline you can provide per my question above!

Melissa, thank you for asking for clarification on this. This means that at any given time, the body functions well with only one teaspoon of sugar in its blood circulation - this isn't to say that the body needs only one teaspoon of sugar per day. Most of us get far more during a typical day from a healthy, well-varied diet that is free of added sugar, and our bodies are constantly working to process these nutrients, shuttle them to our cells, convert simple sugars to glycogen and other forms, etc. The main point I am trying to communicate is that we don't want to take in excess sugars so as to overload our blood circulation, which is what happens when one is following a highly processed diet. The amount of sugar circulating in one's bloodstream at any given time does not represent all of the sugar (glucose, glycogen, acetyl coA, etc.) in the body. Generally, the more active a person is and the more skeletal muscle a person has, the more natural sugars he or she can afford to take in through diet and remain healthy. I hope this helps.

Hello. I have been reading where tiger nuts are a resistant starch the aids in healing of the colon, decreases gut permeability and doesn't spike blood sugar. I would like some advice on using these in a daily diet, and what is the correct way to prepare and consume them safely. There is tiger nut flour, tiger nut snacks, tiger nuts shelled, unshelled, etc. and it is confusing. Thank you.

I'm sorry, Nancy, I am not familiar with tiger nuts. I hope you are able to find reliable information on them and their use.

Very interesting article on blood sugar levels. I am encouraged to alter my ways

I am a vegetarian, rarely if ever eat any sweeets and have totally given up sugar, except I put maple syrup in my coffee - and or honey. Is that something I should not do, or is it ok to use raw organic honey (the maple syrup is also organic) ???
Thank you for this article. I am not diabetic and never expect to be but want to stay healthy when possible. and thank you for allowing my question.

Jean, if you are feeling well and your blood tests show that your glucose and glycated hemoglobin are in healthy ranges, then moderate use of raw organic honey and maple syrup should be fine. The more active you are and the more lean tissue mass you maintain, the more natural sugars your body can use while remaining healthy.

Thanks Dr. Kim for this article, addressing what I regard to be the most pressing issue in our chronic disease epidemics. Keeping blood sugar and insulin low is the one stone that can kill many many health problems simultaneously. I speak as a recovered sugarholic. Our taste buds can ABSOLUTELY POSITIVELY change- I am living proof. As a child I could eat frosting straight up; now, things like tomatoes, corn and even walnuts are perfectly sweet to me! Never going back-not even tempted to! *Even those who don't think they have a sweet tooth may still have blood sugar problems just from eating refined grains, salty carb-rich foods, and even seemingly savory foods that contain lots of hidden sugar. These all raise blood sugar quickly even though not technically sweet to the taste. Flood your body with nutrients (eat the most nutrient-dense foods you can, like colorful veggies, greens, salmon, nuts, avocado, fruit) and after the adjustment phase, you will feel so well and nourished that you will never want to go back! (Of course NOT BUYING junk in the first place helps too. Have family members 'hide' their junk foods from you-out of sight out of mind.) For me, eating real, nutrient-dense, mostly low-carb food has improved weight, mood, energy and oral health.