Is a CGM our best biofeedback tool yet?
In my nutrition coaching practice, the ‘test, not guess’ ethics rule. I hence keep the guesswork to a minimum by making use of functional testing and biohacking devices such as real-time transmission RPM (remote patient monitoring) body scales, blood pressure monitors, BGMs (simple glucometers) and CGMs, or continuous glucose monitors. These in particular have been gaining a lot of traction in the realm of functional medicine and nutrition since their approval for diabetics in 2005, with more and more healthy people autonomously wearing them - and there is no shortage of reasons for that, given the covert presence of sugars and maleficent substances in our food supply. One might say a lack of trust in the pharma-medical-industrial food confederacy is pushing people to explore defense tactics, to save their own lives.
How a Continuous Glucose Monitoring device works
A CGM is a device that is worn 2 weeks at a time; it consists of a sensor that is easily implanted under the skin (usually on the back of the arm, in the tricep area), a transmitter and a receiver. The sensor has a microfilament that goes under the skin into the interstitial fluid between cells, from which it samples glucose automatically, at set intervals of 5 to 15 minutes depending on the model, 24/7. The info then gets wirelessly transmitted to a monitor, or to your smartphone or tablet. Most new devices also feature a high/low value alarm system, which promptly alerts you to take appropriate action.
This biofeedback tool has the potential of putting the kibosh on the tumultuous propaganda and mass confusion about both nutrition and conventional medical treatments for metabolic issues that we are all victims to now. Truth be told, if everyone with a glucose tolerance problem had access to a CGM, much of the loudly marketed industry of cookie-cutter dieting and ‘breakthrough’ supplements would tank in a glorious minute, along with all the fringe medical and sub-medical businesses thriving on diabetes and its dire consequences. There is simply no match right now for the bio-individual insight a CGM provides into the dynamic and variable action of the body with respect to glucose metabolism and insulin sensitivity. By giving you a continuous reading of glucose fluctuations throughout the day, as opposed to the sporadic readings you might obtain by intentionally pricking your finger at isolated points in time, it tells the whole story, not just cherry-picked bits and pieces of it. But, then again, that might just be why allopathic physicians do not prescribe a CGM until it is ‘medically necessary’, as in ‘profitably late’.
Why should I wear one if I’m not sick?
The first concern my clients raise sounds like ‘my doctor says since I don’t have diabetes a CGM really isn’t necessary, how exactly is this useful then?’ Ok, let’s do this by points.
1. Diabetes does not appear out of nowhere, it is a spectrum disease, meaning before you get diagnosed with diabetes you have likely been progressing along a metabolic degenerative spectrum over the course of years, if not decades. This progression happens because of repeated wrong choices, in terms of both food and lifestyle, that lead to insulin resistance, a condition in which cells do not let insulin haul glucose in for energy. When cells become blunted to the insulin nudge, a skewed feedback signal tells the pancreas to pump out more insulin, in an effort to push that glucose into cells. That repeated flooding of glucose in the blood has disastrous consequences such as NAFLD, or non-alcoholic fatty liver disease, inflammation, oxidation and a phenomenon called glycation, by which the free-floating glucose attaches itself to proteins and lipids, coating these molecules and causing damages such as arterial plaque, neurodegenerative disorders, osteoporosis, retinopathy and rapid aging. By the time you are diagnosed with diabetes, all of this damage is already well under way. Moreover, chronic hyperinsulinemia, or excess insulin, triggers de-novo lipogenesis in the liver (the making of fat from carbohydrates and other substrates), makes adipose cells resistant to thyroid hormone and prevents fat oxidation in the muscles, causing us to gain weight.
2. People have an individual response to different foods, even within the same category of macros like carbohydrates. Gaining subjective body awareness is the one and only preventive strategy for people at risk for diabetes. For instance, an individual may have a high insulin response to white potatoes, even when cooled off and turned into a resistant starch food, while another one can eat potatoes in judicious amounts and not present with glucose spikes that raise flags. Moreover, that same second individual who responds better to potatoes, seems to metabolize them even better if paired with protein and/or fat, while individual #1 has an unfavorable response to potatoes even when he/she consumes other macros along with it. One of my clients can eat an apple with lunch without any upswings, while she gets a spike if she eats one with dinner: we progress towards a state of insulin resistance as the day progresses, and in some individuals this shift is more conspicuous than in others. The production of melatonin at night has an impact on both the pancreatic secretion of insulin and the general sensitivity to it, which means the glucose response at night is an all-around less efficient one; interestingly enough though, even in some less glucose tolerant people, after-dark eating does not create any discernibly different glucose response. A CGM allows us to use dynamic internal biomarkers to correlate our subjective experiences with objective metrics that are easy to interpret autonomously; our glucose response to food is influenced by microbiome composition, hormones, shifts in insulin sensitivity, sleep quality, exercise and activity levels, stress, and circadian rhythm adaptations and changes (as in jet lag). All of this kind of damps down the glycemic index piece, doesn’t it?
3. The readout curve is an important piece of information that is virtually absent in scheduled BGM testing. Glucose fluctuations in different environmental contexts is the missing link we are looking for, and it’s where modifiers that are an integral part of life can all be taken into account, in order to form a complete picture. This is paramount to keeping tabs on the progression of metabolic disease, since glycemic variability (high spikes and sudden dips) are associated with more cellular damage and a higher risk threshold for CVD than consistently high values. This means that certain triggering situations like spikes from overdoing coffee while sitting at a desk, or morning spikes due to carryover insulin resistance from eating late at night, can be corrected thanks to measurable and trackable accountability.
4. A CGM will also show glucose highs and lows that we are not used to seeing; that might be daunting at first but it broadens our awareness of our core metabolic functions. For instance, exercising at high intensity will produce a physiological adaptation that is, from a chemical standpoint, a stress response, albeit a hormetic one: when we exercise, the adrenals pump out catecholamines (adrenaline, noradrenaline, dopamine) and cortisol, which elicit a glucose output by the liver meant to make energy substrates available to the muscles fast in a state of perceived crisis. A CGM will hence register a glucose spike during exercise, but the muscles will uptake that glucose fast and in a non-insulin dependent manner, and burn it off as fuel. Likewise, in a low-carb regimen a morning fasting glucose of 100-105 may be due to a phenomenon known as reverse metabolic inflexibility, the implications of which are still unclear, but may have something to do with an overnight glucagon response. There may be glucose excursions in the post-prandial phase that are different than the numbers seen in the classic half hour and two-hour pattern of fingerprick sampling. However, there is a predictability function that shows up as an arrow right by the number, which shows the predicted upward, downward or flat trend the device foresees for those numbers. An upward or downward arrow indicate an expected increase or decrease by 2 or 3 points per minute.
On a final note, it is always a good idea to discuss value ranges with your healthcare provider. This is true whether you have been diagnosed with diabetes or you would like to wear a CGM to gain control over your dietary choices and lifestyle, for the purpose of preventing negative health outcomes, and as a weight management biohacking tool. I regularly volunteer my clients’ doctors, whether they prescribe biofeedback devices or not, so all baseline intents are aligned. That of course comes with its share of pushback, since insurance does not cover these devices for non-diabetic patients, and many doctors are still stuck in the reactive model they were trained for, but oh well.
Sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296129/