Written by Kara Collier
To make the most of your experience wearing a CGM, you need to become an effective N of 1 researcher. In science, when an experiment only has one subject (N=1), this is considered anecdotal and a lower level of evidence. Here; however, N=1 testing is essential, you are here to learn about yourself after all and not just generalized results. To become a proficient N=1 experimenter, we are going to take a step back in time to fifth grade science class and rediscover the tenets of The Scientific Method.
If your memory serves you well, you will recall the following basic steps – formulate a question from an observation, create a hypothesis, test your question, draw conclusions and repeat. Following these basic steps while wearing your CGM will arm you with more reliable and useful conclusions about yourself.
Step One – Formulate a Question
There is no shortage of observations and subsequent questions in the world of health and longevity. These questions may arise from the latest news headline, your great aunt's advice, your favorite podcast, or trends you have noticed about yourself.
For example, you may have observed that grains have become demonized and claim to be bad for glucose levels and overall health, even if they are a whole grain. You particularly love oatmeal and want to see if this is still a good component of your diet, so now your question becomes, will plain oatmeal negatively affect my glucose levels?
Step Two – Create a Hypothesis
Next you suggest a possible answer in the form of a hypothesis. A good hypothesis has two important qualities. One is that it must be testable; an experiment can be set up to test how accurate your prediction is. Second, it must be falsifiable; an experiment can also be devised that might reveal your original prediction is incorrect.
Our hypothesis today is, “If I consume 1 cup of plain oatmeal then I will have a slight increase in glucose, but will stay within normal limits”. This is testable, because we can easily design an experiment to test exactly what is being asked. And it is also falsifiable, we could find that oatmeal actually does push us out of optimal glucose levels.
Step Three – Test Your Hypothesis
When testing a hypothesis, there are a few key factors to keep in mind – controlling your variables and removing confounding factors. This is all to make sure we are truly testing the effect of only oatmeal, and not something else. In this example, oatmeal is the single variable we are studying and there is our independent variable. Our glucose response on the other hand is our dependent variable, because its action depends on the oatmeal.
While testing, it is important to isolate ingredients to tease out confounding factors. If you also put blueberries and peanut butter in your oatmeal, it will be hard to tell what is causing the change in your dependent variable (glucose). If you consume a protein bar 30 minutes after the oatmeal, this will also muddle results. A good rule of thumb is to eat an ingredient in isolation and wait at least 3 hours between eating other foods for a good experiment design.
Introducing other foods into the experiment can muddle the results, and there are many other potential confounding factors to consider as well. Major external factors such as physical activity, sleep, and stress should be held constant as best as possible.
Step Four – Draw Conclusions & Iterate
Now let’s suppose that you design a good experiment and discover that yes indeed, your hypothesis was correct! Glucose levels rose 20 points but remained within normal limits after consuming oatmeal. Now is the science over? Can you firmly proclaim that oatmeal is always good and will never have a negative response? Unfortunately, science is never that simple.
It is essential to be able to replicate your findings.
Let’s propose that you went to repeat your hypothesis and saw that you were not able to produce the same findings – you now have a blood sugar response of 180 (high!) after consuming 1 cup of plain oatmeal.
Now it is time to consider some confounding factors you may have forgotten during your initial experiment design. Running through the mental checklist of influencers is key – physical activity, sleep, stress, hydration, illness, hormones. Suddenly you realize, of course I skipped my morning workout. Now you repeat under more controlled situations (after a workout), and see that your findings were indeed repeated and your glucose remained within normal limits.
Whether your hypothesis was proven correct or incorrect, it always generates a new observation which leads to a new question. From this example, you may produce the following new questions:
Hypothesis #1 – If I do 1 hour of HIIT exercise instead of weight lifting, I will have a lower glucose response.
Hypothesis #2 – If I add 1 scoop of plain protein powder to my 1 cup of plain oatmeal I will have a lower glucose response than without the protein.
Hypothesis #3 – If I consume 1 cup of plain oatmeal as my second meal of the day I will have a lower glucose response than if it is my first meal of the day.
Putting it Together
Thinking like a scientist and testing any idea you may have empowers you with real and valuable data about yourself. The list of ideas to test can go on and on, but below are a few common observations to get your mind thinking about some personal hypotheses.
How do the same portion sizes of carbohydrates from different food affect my glucose? (i.e. carbohydrates from fruit, milk, starchy vegetables, legumes, grains)
How does eating a whole-grain version of a grain change my glucose response compared to eating the refined version? (whole wheat bread versus white bread or steel cut oats versus instant oats)
How does the same portion size of a low versus medium versus high glycemic food affect my glucose? (steel cut oats versus brown rice versus white bread)
How does glucose response to my morning toast change with different toppings? (jam versus peanut butter versus avocado)
How do different types of exercise affect my glucose? (HIIT versus prolonged cardio versus weight lifting)
How do my glucose levels change when I go for a walk after meals?
Does my overall average glucose level change when my workout is in the morning versus the evening?
How do I respond to the same exact meal after 18 hours of fasting versus it being my third meal of the day?
When I eat the same dinner at 5pm versus 10pm, how is my fasting glucose the next morning affected?
Do my overall average glucose levels differ when my time-restricted eating window is between 6am-2pm versus 1pm-9pm?
How does a bad night of sleep affect my glucose levels the next day?
How does an elevated glucose level before bedtime affect my sleep?