- Elevated insulin and blood glucose levels are associated with a wide range of health issues including obesity, mental health, cancer, cardiovascular disease, and stroke.
- “Normal” blood sugars are not necessarily optimal for long term health.
- Most people are somewhere on the spectrum between optimal blood sugars and full blown type 2 diabetes.
- Maintaining blood sugars close to optimum is possibly the most important thing you can do to manage your health, reduce body fat, and slow ageing.
- A diet with a low insulin load will lower blood glucose and allow you to access your body fat for energy.
what is diabetes?
“Diabetes” refers to a group of metabolic diseases where a person has high blood sugars over an extended period of time.
Type 2 diabetes occurs when people become insulin resistant and their blood sugars drift higher. The generally accepted diagnosis levels for type 2 diabetes are:
|“normal”||< 100||< 5.6||< 140||< 7.8|
|pre-diabetic||100 – 126||5.6 to 7.0||140 to 200||7.8 to 11.1|
|type 2 diabetic||> 126||> 7.0||> 200||> 11.1|
Currently one in twelve adults worldwide are classified as diabetic based on this diagnostic riteria. This number is forecast to grow by more than half over the next two decades to 592 million people by 2035. 
Approximately ten percent of people classified as diabetic have type 1 diabetes which is a condition where a person’s immune system attacks the cells in their pancreas and from that time on they have to inject insulin to survive.  While less common, we can learn a lot from type 1s who successfully manage their blood sugars.
what are the risks?
Low carb health advocates such as Dr David Perlmutter,  Nora Gedgaudas , Dr Ron Rosedale  and Dr William Davis  tell us that we should restrict carbohydrate for metabolic and brain health as well as to prevent a range of diseases.
Hba1c  is a test that gives an indication of your average blood sugar over the past three months. The chart below shows one of the more confronting charts from Dr Perlmutter’s Grain Brain  demonstrating that the rate of brain shrinkage with age increases with increasing blood sugar.
This chart shows that an increase in HbA1c is also associated with an increased risk of cancer.
This chart shows that here is a very close relationship between insulin secretion and body mass index (BMI).
These charts show that the risk for cardiovascular disease, coronary heart disease and stroke all increase with higher blood sugar levels.
Antidiabetic medication, even if it reduces your blood sugar, doesn’t help reduce your risk of cardiovascular disease, which is the number one cause of death globally.
The link between your blood glucose control and your chance of requiring a cardiac bypass is hard to argue with. 
Keeping your blood sugar under control is possibly the most important thing you can do to manage your health, manage body fat, gut health, reduce your risk of cancer  and slow aging, regardless of whether you have been formally diagnosed with diabetes.  
Diabetes is expensive. In 2012 it cost the US a quarter of a trillion dollars in hospital costs and lost productivity  and the cost of “diabesity” is forecast to triple by 2050 grow and become a major burden our economy.
what are optimal blood sugars?
If you’re not a diabetic getting your HbA1c checked by your doctor regularly you can use your average blood sugar values from a home blood glucose metre to see how you’re tracking compared to optimal. Blood glucose metres are available readily online or at your local chemist. You can pick them up for less than $10. The higher end ones will also measure your blood ketone levels. 
The conversion between HbA1c and average blood sugar are shown in the table below. I have also shown various risk levels based on the cardiovascular disease data above. If you want to calculate your average blood sugar simply take the average of all your blood sugar tests – fasting, before meals and after meals.
|risk level||HbA1c||average blood sugar|
|excellent||< 5.0||< 5.4||< 97|
|good||< 5.4||< 6.0||< 108|
|danger||> 6.5||> 7.8||> 140|
Comparing the diabetes diagnosis criteria in the first table with these optimal levels it’s clear that blood sugars that are considered “normal” are far from optimal.
By the time you’re “pre-diabetic” you’re well into the danger zone. By the time your blood sugars become elevated it’s likely that your pancreas has been trying to pump out extra insulin for some time and you are well and truly losing the battle of metabolic health. Dr Ron Rosedale says that if you’re exposed to modern processed foods then it’s likely that you are somewhere on the spectrum between optimal and full blown diabetes. 
Doctor Richard Bernstein recommends an ideal blood sugar of 83mg/dL (or 4.6mmol/L) for type 1 diabetics.  Paul Jaminet notes that the optimal range for blood sugar is between 70 and 100mg/dL (3.9mg/dL and 5.6mmol/L). 
A type 1 diabetic will carefully balance their carbohydrates and insulin doses throughout the day to try to keep their blood sugar within this narrow range. However this is impossible on the diet recommended to them in line with the Food Pyramid / MyPlate with lots of “healthy whole grains”.
The continuous glucose monitor plot below shows the typical blood sugar roller coaster experienced by a type 1 diabetic. This style of blood sugar fluctuation occurs to some extents in all of us to some degree, depending on our diet and our insulin sensitivity.
what does insulin do?
The hormone insulin allows us to clear excess sugar from the blood and store it for later as body fat. This adaptation was a great advantage for our ancestors who would consume sweet fruits in summer and store some body fat for winter. It’s said that our ability to store fat via insulin enabled your ancestors to survive through the ice age.  The people who couldn’t do this so well aren’t your ancestors, if you know what I mean.
Achieving nutritional ketosis is all the rage these days, but what it means in simple terms is that you have low enough levels of insulin to enable stored body fat to be used for energy.  If your insulin levels are too high you’ll end up storing more of your food as fat. You’ll then need to eat extra to make it through the day. 
In the next article we’ll look at what you can do to normalise your blood glucose levels by choosing foods with a low insulin load.