The Impact of Continuous Glucose Monitoring and Food Diaries on Glucose Levels and Lifestyle Choices

Elevated blood sugar levels and post-meal sugar spikes can significantly impact health, potentially leading to the development of chronic diseases over time. I gathered a group of 10 individuals to use continuous glucose monitors (CGMs) for two weeks to demonstrate how glucose impacts our bodies and help people understand how different foods might affect the so-called "glucose roller coaster" or large sugar spikes. By utilizing CGMs, participants can monitor their blood glucose levels in real-time, enabling them to make more precise and informed decisions. This real-time monitoring empowers individuals to take proactive steps towards adopting healthier dietary habits that can benefit them for the rest of their lives. 

Continuous Glucose Monitors (CGMs) provide real-time blood glucose updates via an accurate body-attached device. Many of the blood glucose monitoring regimen feels quite unsustainable, requiring frequent finger pricks and test strips several times a day. Continuous glucose monitoring (CGM) is much more convenient. CGM technology has simplified monitoring from frequent finger pricks to smartphone swipes. Some of the more advanced CGM devices even allow you to bathe and swim while wearing them. Your CGM system will come with an applicator, and though each model is different, the instructions generally include cleaning an area on your arm or abdomen with an alcohol wipe to any oils, letting the alcohol dry while you place the new sensor in the applicator, positioning the applicator on the cleaned area and pushing down on the device or button, connecting the transmitter to the sensor by pressing it into place, and using the included receiver or your smartphone to begin monitoring your glucose levels. The applicator inserts the needle sensor into the subcutaneous adipose tissue (the fat tissue under the skin), where it can contact the interstitial fluid between your cells, which delivers oxygen and nutrients from your capillaries. The sensor then measures your interstitial glucose levels. The accuracy of certain meters is evaluated by determining the MARD (mean absolute relative difference), which measures the difference between a meter’s result and the corresponding laboratory measurement. A MARD less than 10% is considered “good analytical performance.” Clinical data for the freestyle libre, one of the most popular CGM systems, shows a MARD of less than 8%.

Understanding glucose levels is crucial for managing overall health, especially in relation to diabetes. Glucose serves as the primary energy source for the body, vital for functions like brain activity and physical performance (Edwards, 2023). However, disruptions in glucose regulation, such as insufficient insulin production or insulin resistance, can lead to elevated blood sugar levels, a hallmark of diabetes (National Diabetes Statistics Report, 2017). Type one diabetes results from the immune system essentially fighting insulin-producing cells in the pancreas, while type two diabetes involves decreased insulin production and insulin resistance (Mayo Clinic, 2023; UVA Health, 2019). Diabetes affects a grand majority of the population, with over 34 million Americans diagnosed, and it significantly increases the risk of developing cardiovascular diseases and other detrimental conditions including cancer, and strokes. Six in ten Americans grapple with at least one chronic disease (American Diabetes Association, 2023).  Moreover, diabetes has been connected to cognitive decline and an increased risk of developing dementia. This is due to the fact that diabetes and dementia share molecular characteristics and hypoglycemia (Budson, 2021).  Regarding the relationship between sugar and heart health, there are a number of indirect relationships. For example, excessive consumption of sugar overloads the liver. According to Dr. Hu, your liver processes sugar the same way it processes alcohol. It turns dietary carbohydrates into fat, eventually leading to a bigger buildup of fat, which may then develop into fatty liver disease, a factor in diabetes, which increases your risk of heart disease.  Tragically, these persistent health conditions remain the primary causes of death and disability in the United States, placing a significant burden on individuals (JAMA internal medicine, 2014). Dr. Hu and his colleagues’ pursued a 15 year trial and found out that those who consumed 17% to 21% of their calories as added sugar had a 38% higher chance of dying from cardiovascular disease than those who consumed 8% of those calories. Excessive sugar consumption in sugary beverages also contributes to weight gain by tricking your body into turning off its appetite-control mechanism because liquid calories are not as full as calories from solid foods.  As a result, drinking sugary beverages makes it easier for people to increase the number of calories in their regular diet (Harvard health publishing, 2022).

The study assesses glucose levels before meals and the maximum spikes after meals and evaluates the impact of wearing a Freestyle libre CGM and maintaining a food diary on lifestyle choices and health. The study seeks to address gaps in research concerning the effectiveness of personalized dietary strategies, the long-term health implications of real-time glucose monitoring, the impact of glycemic variability on health outcomes, the effectiveness of educational interventions in promoting behavior change, and the integration of CGM technology into clinical practice. The participants ranged from young adults to middle aged individuals with fairly healthy eating habits to individuals with pre-diabetes. For the first week the participants ate as usual (their normal diet) and they recorded their pre and post meal blood sugars and filled a specific food diary where it clearly stated the days of the week, next to it the “meal” and glucose # “before eating” and the “highest peak after eating.” At the end of the first week the participants were given specific strategies and food recommendations to mitigate elevated blood sugar levels and prevent post-meal sugar spikes. During the second week, participants continued to fill out their food diary as in their first week but now they incorporated specific strategies and food recommendations that help mitigate sugar spikes. The strategies included having a well balanced breakfast, like Two-egg omelet with tomatoes and feta, Toast with smoked salmon and cream cheese, Unflavoured Greek yogurt, nut butter, seeds and whole fruit, and Chia seed pudding. Other hacks included adding vinegar. Research shows that drinking vinegar before a meal will curb the glucose spike of what you eat afterwards by up to 30% (without you needing to change anything about the meal you're about to have). Participants that corporated this hack poured one tablespoon of vinegar (any kind of vinegar, except balsamic as it contains extra sugar) in a tall glass of water. Some participants also added veggie starters before meals. When you eat it at the beginning of a meal, the fiber has time to deploy itself in your digestive tracts and create a protective mesh in your upper intestine. This mesh then reduces the absorption of any glucose molecules coming down during the rest of the meal, again meaning that you get to eat the exact same meal as before, but with less of an impact on your glucose and on your body. Some other hacks included using natural sweeteners like Monk fruit and Stevia powder (natural green or refined/white), and taking Supplements to lower the spike. Some supplements included Berberine, Magnesium, Cinnamon, Zinc, Probiotics, and Vitamin D. Hacks that were Recommended for if you are having cravings included Essential oils - lavender, grapefruit, peppermint and or/ fennel oil, Xylitol gum (example: Pur, Spry, Epic), Zevia Soda (stevia sweetened soda), Electrolyte water, and Herbal teas (make sure they’re natural without added ingredients. Some of the best ones to curve your appetite and help your sugar metabolism are ginger, turmeric, fennel, lemon balm.  Both first and second week blood sugar averages and post-meal glucose spikes were then compared. We took the average delta of the first week and compared it to the second week. During the first week, post meal sugar spikes were higher, reflecting their usual dietary habits. In the second week, after implementing personalized dietary strategies, average blood glucose levels decreased (to ____), demonstrating a significant improvement in glucose management. Graphical representations of daily glucose profiles revealed fewer post-meal spikes and more stable trends throughout the day. Participants reported positive experiences with the dietary adjustments, noting better awareness and control over their blood sugar levels. Lastly, participants filled out a questionnaire that is attached in the food diary where 100% of the participants recommended a CGM to family members, and friends. Participants answered other questions like “do you think you eat healthy?” “Will you make healthier food choices?” “Will you incorporate some specific strategies and which ones?” and “Do you believe that wearing a CGM and learning will help you live a healthier and happier life?” Participants reported positive experiences with the dietary adjustments, noting better awareness and control over their blood sugar levels.