Continuous Glucose Monitors (CGMs) are becoming an increasingly popular tool for assessing and optimizing individual health and nutrition. However, a recent study, “Imprecision Nutrition? Intraindividual variability of glucose responses to duplicate presented meals in adults without diabetes,” raises important questions about their precision and reliability in individuals without diabetes, particularly when assessing postprandial glucose (PPG) responses. The study highlights significant variability in glucose responses to the same meals, emphasizing the complexity of individual metabolic responses and cautioning against overreliance on CGM data without proper contextualization.
One key takeaway from the study is that glucose responses can vary even when duplicate meals are consumed by the same individual under seemingly identical conditions. This variability may arise from a multitude of factors, including stress levels, physical activity, gut microbiota diversity, sleep quality, hormonal fluctuations, and even subtle differences in the timing of meals. Such findings underscore the idea that CGMs provide snapshots of glucose trends rather than definitive metrics that alone dictate precise nutritional adjustments.
The Role of Key Influencing Factors
- Exercise: Physical activity can dramatically alter glucose regulation. A meal following a period of exercise may produce significantly different glucose responses compared to the same meal consumed during sedentary periods.
- Meal Order and Composition: The sequence in which foods are eaten—e.g., consuming fiber or protein before carbohydrates—has been shown to impact glucose responses. CGMs highlight these effects, revealing patterns that inform dietary strategies for better glycemic control.
- Sleep and Stress: Sleep quality and duration, as well as acute or chronic stress, influence glucose metabolism via hormonal changes like cortisol and insulin sensitivity. Variability in CGM readings can often reflect these states rather than dietary differences alone.
- Other Non-Quantifiable Factors: CGMs also indirectly capture effects from factors like gut microbiome diversity, hormonal shifts (e.g., during different phases of the menstrual cycle), and immune health, even though these influences might not be easily quantifiable through glucose data alone.
When considering a CGM sensor, it is important to recognize the following points. CGM’s are not 100% precise or accurate for every individual. The utility of these devices lies in their ability to reveal long-term trends rather than single or sporadic readings. Data collected over two to three months—or more—offers a more accurate depiction of a person’s overall metabolic health and response patterns. Isolated readings, while not fully reliable for drawing sweeping conclusions, can still offer valuable insights. For instance, a sudden spike in glucose may indicate stress, a gut health imbalance, or heightened sensitivity to specific foods, while a steady trend could help evaluate the efficacy of dietary or lifestyle modifications.
CGMs, when used thoughtfully with a qualified dietician, nutritionist, physician or other qualified healthcare provider, can also inform patients about actionable steps they can take in real time. For example, if a meal unexpectedly spikes glucose levels, it could signal the need for a higher-protein, fiber-rich subsequent meal or encourage a physical activity break to improve glucose uptake. Similarly, poor glucose control during specific time periods may point to lifestyle areas for improvement, such as enhancing sleep quality or stress management techniques. While these moments of insight are useful, they are most meaningful when framed within the broader context of trends and paired with additional clinical evaluations like blood work, hormonal assessments, nutritional intake and lifestyle patterns.
The findings from this study should not discourage the use of CGMs but rather temper expectations about their precision and highlight the importance of proper interpretation. Variations in glucose response among individuals to identical meals reflect the profound individuality of metabolism—a concept central to functional and integrative medicine. Food sensitivities, gut health, hormonal states, blue light exposure and even immune function play significant roles in determining blood glucose levels. Recognizing these nuances can enhance how CGMs are integrated into precision nutrition planning without overestimating their standalone value.
As a tool, CGMs can empower patients to become more engaged in their health by providing dynamic feedback. Yet, their insights are most effective when combined with other health data points, such as biomarkers for inflammation, lipid profiles, and assessments of physical activity and stress. When viewed through a holistic lens, CGMs serve as a helpful guide, not an absolute arbiter, in crafting sustainable and personalized dietary strategies.
While CGMs may not deliver absolute precision in every scenario, they remain a valuable resource for understanding glucose dynamics and metabolic trends over time. Educating patients about their potential and limitations ensures that these devices are used appropriately and constructively. By integrating CGM data with other contextual health metrics, clinicians and patients can make more informed decisions about diet, lifestyle, and overall health management. Properly leveraging CGMs in this balanced manner offers the potential to bridge the gap between data collection and actionable, meaningful health outcomes.
Moving forward, it would be important to do a comparative analysis of the existing technology and highlight the CGM companies providing more accurate biological data to further support trend analysis for better health outcomes. While this study included only two different sensors, there are over five current CGM companies on the market. A comparison of these devices has yet to be reported.
At our practice, we support patients with prediabetes, diabetes, insulin resistance and metabolic health optimization. Our personalized approach integrates tools like CGMs with a comprehensive evaluation of dietary habits, lifestyle factors, and metabolic health. If you’re interested in learning more about how we can work together to optimize your health and well-being, please reach out to us at 646.627.8000, fill out this form for a complementary discovery call, or email Bridget@drbojana.com.
Reference:
1. https://ajcn.nutrition.org/article/S0002-9165(24)00814-1/fulltext