Personal Science Week 230525 Glucose Drink
Testing a glucose-lowering soft drink
This is a weekly update for curious people who like to apply the scientific method in their personal lives.
This week we show an experiment wearing a CGM to test a new soft drink. You can think of this week’s post as a followup to the extensive CGM discussion we did back in PS Week 230406.
Personal Scientists love CGM for its always-on, 24x7 data collection and the way it gives immediate feedback about how your body reacts to the food you eat.1
A Food Experiment
A recent PROTO.LIFE review, “No Spike, No Crash”, by Jacopo Prisco reminded us to dig up an old experiment we did a few years ago. Prisco describes his experience with a new soft drink that claims to be a clinically proven way to reduce your body’s glucose spikes after a meal. The drink, Good Idea, is made by the Swedish entrepreneur behind the oat drink, Oatly. With several million dollars’ worth of sales and some new sponsorships, you can expect to hear more about Good Idea, as well as a slough of similar products that promise to help manage your body’s metabolism. But Personal Scientists don’t just listen to the marketing fluff, and we’re skeptical of clinical trials done on other people. After all, who cares whether it reduces glucose in other people — what you really want to know is how well it reduces glucose in you.
To see how well Good Idea works, I ran the following experiment:
Wearing a Freestyle Libre™ continuous glucose monitor (CGM) on five different mornings on an empty stomach, I ate a bowl of Cream of Wheat mixed with 1/4 cup heavy cream and 1 TBS butter. This meal is about 500 calories, including 50g of net carbs and 35g of fat. I wanted a food that is generally considered “healthy”, with no sugar content, but high carb. I served it with a generous amount of fat to avoid significant glucose spikes.
I ran my results through my open source R analysis package cgmr, which lets me read the Freestyle Libre raw data and convert it into the following plot2.
This plot shows how my body’s glucose levels changed over the first two hours after eating these standardized meals. On all five days, I ate exactly the same portions. The only difference was that on one of the days, I also downed a can of Good Idea about fifteen minutes before the meal.
You can see the final score better from the following table which shows the total change in glucose that I experienced over the course of two hours. Min and Max show how much the glucose changed, and Rise is the level change at the end.
IAUC (“Incremental Area Under the Curve”) is a standard method that nutrition scientists use to calculate the overall effect of glucose changes. It uses a simple sum of the area of all the trapezoids under the curve marked out by the various CGM measurements. Generally, lower is better. A value of 0 would mean no change at all.
Bottom line: Good Idea seems to have worked, at least in this very small experiment. Of course, with only one data point that includes the drink, this could easily be a coincidence, so to really prove this I would want to run a few more examples with and without the drink.
Oh, and a short disclaimer: I have no connection whatsoever with the company or the drink. I did this experiment purely for fun.
And one plug: my friends at Tastermonial are always looking for Personal Scientists willing to wear a CGM while enjoying new food products. Sign up at their web site.
About Personal Science
Listen to experts, but be skeptical. That’s the idea behind Personal Science, where we use the techniques of science to understand and solve personal questions. Often, but not always, Personal Science involves quantitative or statistical reasoning based on self-collected raw data, but the overall thought processes can apply to every aspect of daily life.
In general, Personal Science requires a skeptical, yet open-minded curiosity about the world, humility in the face of incomprehensible complexity, and a constant desire to be proven wrong. Personal Scientists, above all, rely on their own direct experience, never taking somebody else’s word for it. Nullius in verba — take no one’s word for it.
As always, if you have other ideas you’d like to cover in a future Personal Science Week, let us know.
You can read much more at our (free) ebook at https://diycgm.com where we remind you: please don’t pay hundreds of dollars for one of those fancy commercial glucose-measuring products. They use the exact same stick-on hardware device you can get at Costco for under $50).