Glucose Monitoring: Perfecting Your Low-Carb Keto Diet

The ketogenic (keto) diet is a high-fat, low-carb diet that helps with weight loss and blood sugar control. When following a keto diet, blood glucose readings trend downward. This is because eating fewer carbs means you're decreasing the available glucose that can be absorbed into your bloodstream, so your blood sugar levels will be lower.

To track how the keto diet impacts your blood glucose levels, you can use a continuous glucose monitoring (CGM) device. This is an FDA-approved tool that takes sample readings of glucose levels every fifteen minutes by measuring the glucose in the interstitial fluid beneath your skin.

While your body is in ketosis, you can expect your CGM device to report readings of 70-90 mg/dL (3.9 mmol/L) or slightly below these values.

How to measure blood glucose

Blood glucose measurement is a screening tool for diabetes mellitus (diabetes). It is also an important tool for assessing unwell patients, especially the young or old. Potentially life-threatening extremes of blood glucose can be detected, enabling the patient, carer, or health worker to respond to high (hyperglycaemia) or low (hypoglycaemia) blood glucose by adjusting the diet or using insulin.

When to Measure Blood Glucose

Blood glucose should be measured whenever a patient with diabetes is feeling unwell. It should also be measured before surgery to ensure the patient does not become unwell during or after the procedure. In newly diagnosed diabetes patients, more frequent measurements are needed until blood glucose is stable.

Patient Safety and Comfort

It is important to be aware of what 'normal' blood glucose levels are. Find out what is 'normal' for individual patients by asking them and/or checking their notes or file. Take universal precautions when handling blood and use aseptic techniques when puncturing the skin. While it would be unusual for infection to occur, patients with diabetes tend to heal less well and may not deal as well with infection.

Wash your hands and put on gloves. Choose the site for the blood sample: usually the side of a finger, but the arm or thigh may be used (change the site if frequent measurements are needed). Use an alcohol swab to clean the site and let the alcohol dry.

Insert a test strip into the monitor, following the instructions. Use a single-use lancet or a lancing device to draw blood and dispose of it in a sharps container. Apply the blood to the testing strip; some strips need the blood drop to be over the whole test pad, while others suck up the blood directly from the site of the bleeding.

Place an alcohol swab or a piece of gauze over the site and hold it there, or let the patient hold it there until the bleeding stops. Monitor for excess bleeding. Read and record the result, reporting and/or responding to abnormal readings. Tell the patient what the result is, explain it, and discuss options. Dispose of all used equipment safely, in line with hospital or healthcare policies.

Calibrating the Blood Glucose Monitor

Calibrate the monitor and each new pack of test strips together. Calibrate the monitor each week. Place the control solution on a test strip and check that the value shown on the monitor matches the value on the bottle (or the pack of strips it accompanies). Record the calibration readings. If one is provided, use the check strip to ensure that the meter is working.

Blood Sugar, Insulin Resistance, and Disease

Insulin resistance is a condition in which the body does not respond adequately to insulin, a hormone produced by the pancreas that is essential for regulating blood sugar levels. Insulin is responsible for moving glucose from the blood into cells, where it is used for energy or stored for later use. In a state of insulin resistance, cells in the muscles, fat, and liver do not respond effectively to insulin, resulting in elevated blood glucose levels.

The primary marker for determining diabetes risk is blood glucose levels. As blood glucose levels rise, the risk for various life-threatening conditions, most notably heart disease, also increases. Since the 1950s, diabetes rates in the US have increased more than sevenfold, driven by a dramatic increase in sugar consumption. However, the relationship between dietary sugar intake, high blood sugar, and diabetes is more complex than a simple cause-and-effect relationship.

Insulin resistance develops when the body is consistently overloaded with sugar, leading to a state where insulin is no longer able to effectively store blood sugar in muscle and liver cells. This results in high blood sugar levels for prolonged periods, which is the hallmark of Type 2 Diabetes. Additionally, insulin resistance is a key underlying factor in many other chronic diseases, including heart disease, cancer, and Alzheimer's disease.

The good news is that insulin resistance can be managed and even reversed through lifestyle modifications. Strategies such as regular exercise, fasting, adopting a ketogenic diet, and getting adequate sleep can improve insulin sensitivity and help regulate blood sugar levels. Furthermore, measuring blood glucose levels through continuous glucose monitoring can provide valuable insights into how different foods and lifestyle factors influence blood sugar, enabling individuals to make informed choices to support their health.

In summary, insulin resistance is a complex condition that can have significant health consequences. However, by understanding the underlying causes and implementing appropriate lifestyle changes, it is possible to manage and even reverse insulin resistance, thereby reducing the risk of developing Type 2 Diabetes and other chronic diseases associated with this condition.

Adaptive Glucose Sparing

On a ketogenic diet, the body's cells are fuelled by fatty acids and ketones instead of glucose. This means that the body's requirement for glucose is much lower. The majority of glucose is spared for tissues with an absolute requirement for it, such as the brain.

As a result, muscle tissue "refuses" glucose to keep it available for the brain, leading to slightly elevated glucose levels circulating in the blood, especially in the morning. This is a healthy and normal response to a very low-carbohydrate intake.

People on a ketogenic diet may experience higher fasting blood glucose levels, but this does not necessarily indicate issues with blood sugar control. In fact, a ketogenic diet is often recommended for people with type 2 diabetes as it can help enhance metabolic flexibility, reduce insulin levels, and manage glucose levels.

To fully understand metabolic health, it is important to measure not only blood glucose levels but also HbA1c (average blood glucose over 2-3 months) and insulin levels. This is because the relationship between glucose and insulin is crucial in maintaining stable blood sugar levels.

In summary, adaptive glucose sparing is a natural adaptation that occurs when the body has been on a long-term ketogenic diet, and it helps ensure that the brain has sufficient glucose to function properly.

How Long Does it Take for Keto to Improve Insulin Resistance?

The ketogenic diet has been shown to improve insulin resistance in a short amount of time, with some studies showing a 75% increase in insulin sensitivity. The degree to which this improvement is maintained in the long term depends on the individual. Factors such as the duration of insulin resistance and physical activity levels may play a role in determining an individual's level of carbohydrate tolerance after a successful period on a well-formulated ketogenic diet.

The ketogenic diet works by reducing the intake of carbohydrates, which are broken down into glucose and used as energy by the body. By limiting carbohydrates, the body is forced to use alternative sources of energy, such as fatty acids, which are converted into ketone bodies. This process is known as ketogenesis, and it replaces glucose as the body's primary source of energy.

The ketogenic diet has been found to be particularly effective in treating insulin resistance in obese and overweight individuals, as well as those with type 2 diabetes. In addition, the ketogenic diet has been shown to lower fasting insulin levels compared to moderate and low-fat diets in these populations.

The ketogenic diet has also been found to be beneficial for endurance athletes concerned about insulin resistance or elevated glucose levels. A 2014 study found that a low-carbohydrate ketogenic diet helped lower insulin levels and improve recovery in athletes.

Optimal fasting blood sugar ranges

If your fasting blood glucose level is 100 to 125 mg/dL (5.6 to 6.9 mmol/L), it usually means you have prediabetes. People with prediabetes have up to a 50% chance of developing Type 2 diabetes over the next five to ten years.

If your fasting blood glucose level is 126 mg/dl (7.0 mmol/L) or higher on more than one testing occasion, it usually means you have diabetes.

How to Measure Fasting Blood Sugar

Fasting blood glucose is your blood glucose level after an overnight fast of around 12 hours. To get an accurate reading, it's best to wait an hour or more after waking up to take your fasting blood glucose, and longer for people with insulin resistance.

Managing Your Fasting Blood Sugar

• Exercise: Physical activity increases insulin sensitivity, the opposite of insulin resistance. Both endurance exercise and weight training have been shown to have positive effects.
• Fasting: Nothing lowers blood glucose and insulin levels like not eating. Start with 16-hour intermittent fasts, and work your way up as comfort and schedule permit.
• The keto diet: The ketogenic diet severely limits carbs, helping minimize the blood sugar response.
• Measure your blood glucose: Knowing how blood sugar fluctuates with different foods helps you make smarter choices.
• Spice and supplement: Spice your food with turmeric and cinnamon, or consider supplementing with berberine, to limit your blood sugar response.
• Sleep well: Sleep is crucial for insulin function. Prioritize it.

Frequently asked questions