Fasting glucose (blood sugar) is tracked in the progression and maintenance of diabetes, but we often follow medical advice regarding these numbers without truly understanding their meaning. Blood glucose is the main sugar that the body makes from the food in the diet. Glucose is carried through the bloodstream to provide energy to all cells in the body. Cells cannot use glucose without the help of insulin. A fasting glucose test is a measure of the amount of glucose (sugar) in the blood after an overnight fast. Insulin is a hormone that is produced and stored in the beta cells of the pancreas. Insulin helps transport glucose from the blood to within cells, thus helping regulate blood glucose levels, and has a role in lipid metabolism. A serum insulin test measures the amount of insulin in the blood.
Fasting glucose (blood sugar) is tracked in the progression and maintenance of diabetes. A fasting blood sugar over 125 mg/dL on two separate occasion is considered diabetes. Fasting blood sugar 100-125 mg/dL is considered elevated and is now given the diagnosis of “pre-diabetes.” Less than 100 mg/dL is considered normal.
The fundamental flaw of this tracking metric is that high blood sugar does not CAUSE diabetes. High blood sugar is the RESULT of the true cause of diabetes, insulin resistance. When we eat things that raise our blood sugar, insulin is released to clear that glucose from the blood. This is the natural response of the body. However, when we constantly eat things that spike our glucose, more and more insulin is released. Eventually, the insulin receptors will no longer respond to the insulin. This is called insulin resistance. As a result of insulin resistance, the glucose will not be cleared from the blood effectively, resulting in high blood sugar. The problem with only tracking fasting glucose is that insulin resistance begins long before we develop elevated blood sugar. The earlier we can become aware of dysfunction, the easier it is to intervene with lifestyle changes to stop, and even reverse, the progression. Tracking insulin, therefore, gives a better picture of the true underlying cause of the problem. If your fasting glucose is 98, you would be given a “normal” checkmark on the diabetes scale and sent on your way. Although this is considered normal based on medical diagnosis, there are likely signs of insulin resistance already in place to have a number this high on the “normal” scale. Having all the information is crucial to understand your health and how lifestyle changes are impacting your health. By monitoring insulin levels, you will have a better understanding if you are experiencing insulin resistance.
It’s also crucial to understand that your lifestyle (i.e. diet and exercise) is the only thing that can directly impact insulin sensitivity, not medications. If you fall into the pre-diabetes category, lifestyle changes should be the number one priority. However, medications are more commonly prescribed to help lower those blood sugar levels. What’s the issue with this? Lowering those numbers with medication does not address the underlying issue. Medications do not improve insulin sensitivity, they simply control the symptom (high blood sugar). This would be like having a broken bone and taking pain medication. The pain medication may reduce the symptom (pain), but it is not fixing the cause of the pain (broken bone).
Fasting is one key to controlling insulin. Refined sugars spike insulin the most, followed by other carbohydrates and proteins. Fat has little effect on our insulin. The low-fat craze our society adopted has led to an increase in carbohydrate consumption, which is likely responsible for the increased insulin resistance we are seeing. We also eat constantly throughout the day, often from the minute we wake up until we go to bed. Our bodies are never given periods of time to truly rest and digest. Our blood sugar will naturally fluctuate throughout the day, however maintaining as stable a level as possible and avoiding the big spikes is best. When we fast, we avoid blood sugar spikes, which gives our bodies time to reset and is one of the best things we can do to prevent insulin resistance. Regular exercise also improves insulin sensitivity and helps manage blood glucose levels.
It’s important to remember elevated blood glucose is not the cause of diabetes, it is the result of insulin resistance. When insulin receptors are not functioning properly, glucose will not be cleared form the blood and blood sugar levels will rise. By the time clinically “high” blood glucose is present, years of metabolic damage has been done to the body. Tracking blood sugar is certainly important, especially during times of fasting and when managing diabetes. However, we should be intervening long before the “pre-diabetes” phase. As your levels approach the high end of normal, you are likely experiencing insulin resistance. Tracking insulin levels and making lifestyle changes that will increase insulin sensitivity is the only way to prevent diabetes.