Healthy Breakfast Quest: A Tale of Two Oatmeals

Bill takes two things seriously, breakfast and data, and he explores his options in this article.

Oatmeal breakfast and glucose
Bill Tancer
— Signos
Chief of Data Science
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Reviewed by

Bill Tancer
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Updated by

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Science-based and reviewed

May 17, 2024
August 10, 2021
— Updated:
April 27, 2022

Table of Contents

I take two things very seriously, breakfast and data, so when I undertook the task two years ago to find a healthy breakfast—no, actually, the healthiest breakfast—I turned to peer-reviewed research to find some evidence-based guidance. What I settled on, based on my research, was rolled oats, cooked with water, not milk, topped with flax meal, blueberries, almond butter, nuts, and banana. Fiber—check, antioxidants—check, healthy fats and protein—check.

Sure it was a carby meal, but my research indicated that oatmeal (without added sugar) is a blood sugar-stabilizing food. So, I was off to the races. For two years, I ate my variation on my well-researched healthy breakfast theme.

Healthy Breakfast Test: My Glucose Response to Oatmeal 1

Fast forward to April 2020, I applied a continuous glucose monitor and began monitoring my glucose levels. Given what I had found in the research, I was prepared for a boring first meal glucose graph. What showed up on my Signos app, however, was anything but boring—albeit a bit discouraging.

My glucose level went from an acceptable 80mg/dL to a spike of 187mg/dL. For reference, a fasted blood sugar of 127 is considered to be diabetic.

<p class="pro-tip">Read more: Why your blood sugar can be higher in the morning?</p>

I've been trying to lose 10 pounds for the last two years and thought that I was eating a smart, healthy breakfast. I was eating smart for the average person, but as it turns out I was eating completely wrong considering my body’s response and resulting glucose levels.

How Glucose Affects Your Weight

So why does blood sugar matter when you’re trying to lose weight? The simplified answer is that your body has three choices when it comes to the food you eat:

  1. it can use the food for energy
  2. it can excrete it
  3. it can store the glucose from the food for later use.

When we eat sugar in excess, those calories are stored as fat. By keeping your blood sugar low after meals, you’re able to lose fat versus gaining fat.

Back to my breakfast. I wasn’t willing to give up my morning oatmeal (I’d grown to be a fan), so I turned to the Signos app, which provided a suggestion: remove the banana.


According to the NutritionData site, a medium-sized banana contains 14g of naturally occurring sugars<sup>1</sup>, but the glycemic load for that same banana was scored a very low 10 (or 1/100th of your daily recommended glycemic load). Based on the low glycemic load, I didn’t think the change would make a difference.

<p class="pro-tip">Read more about oatmeal and weight loss</p>

Healthy Breakfast Test: My Glucose Response to Oatmeal 2

I was wrong. The very next morning I decided to test out the suggestion. I carefully measured all of the oatmeal’s ingredients sans banana and added raspberries for extra sweetness. The result: for the two-hour period following breakfast, my blood sugar barely budged from a glucose level of 85mg/dL.

Why didn't the glycemic index and existing research on oatmeal and bananas match my anecdotal results?

In 2015 a study published in Cell demonstrated that, largely due to microbiome differences in individuals, the glycemic response to a food might differ from person to person<sup>2</sup>. Perhaps what I was seeing. I am more sensitive to the sugars in a banana than those who participated in research behind the Glycemic Index.

As a side note, I’ve eaten oatmeal sans banana since April with no blood sugar spikes and lost 14 pounds in the process.

After reading an article on the sugar-blunting properties of resistant starch (green bananas contain a good amount of resistant starch) I have added underripe bananas to my healthier breakfast. I cook the green bananas with the oatmeal and water in the microwave. My revamped oatmeal keeps my blood sugar low. Cue thunderous applause.

Now, back to breakfast.

<p class="pro-tip">Read more: Should you work out before eating breakfast?</p>

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About the author

Bill Tancer is a New York Times best-selling author. He is a co-founder and the chief data scientist at Signos and the creator and host of Signos’ podcast, Body Signals.

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