Oatmeal Fast: A Metabolic Reset — The Results Are In, by Roxana Soetebeer MHP PHC



Oatmeal Fast: A Metabolic Reset — The Results Are In

The oatmeal fast is an unconventional approach in a world where dietary dogmas often persist. Designed as a short-term metabolic reset, it has its roots in the work of Dr. Carl von Noorden, a pioneer of very-low-carb diets. In this blog, I share my personal experience with the oatmeal fast, including surprising results, some science, and lessons learned along the way. Whether you're curious about improving metabolic flexibility or simply looking for tools to break through a plateau, this might just be the experiment for you.

I promised to share the results—good or bad. Now, after completing the experiment, I'm excited to report back. This blog is a follow-up to my initial post, where I outlined my intentions and expectations.

Beyond Keto — Options to Improve Metabolic Health

When I first mentioned the oatmeal fast, reactions were intense. As someone who's followed a very-low-carb ketogenic lifestyle for over five years, the notion of introducing oats into my diet was unthinkable to some. People accused me of "losing my way" or using this as an "excuse to eat carbs." As if I would choose oatmeal as an excuse to eat carbs.

Their dogmatic reactions reminded me of the tribal nature of modern dietary camps—which I am used to from the vegan camp but didn't expect so much from the keto camp. As I suggested a change from the accepted belief set, nasty comments kept rolling in. Surprisingly, not on X, but on my Facebook page. If my experience with keto taught me anything, it's that nothing is written in stone. Even seemingly outlandish ideas should not be outright ignored, especially not when backed by solid science.

When I adopted keto, my entire understanding of nutrition changed. I realized much of what I'd been taught—like eating 300 grams of carbs daily, 3 meals and 3 snacks to supposedly keep glucose levels stable, or fearing saturated fat—was deeply flawed. Keto taught me to challenge conventional wisdom and check out what truly works for my body. So why not apply that same open-mindedness to the oatmeal fast?

Why Call It a Fast?

Some have questioned why the oatmeal fast is called a "fast" since it involves eating. While traditional fasting means abstaining from all food, in this context, it refers to a highly controlled, minimalist protocol aimed at achieving specific metabolic benefits. Like fasting, it reduces overall caloric intake, stabilizes glucose, and prompts metabolic flexibility. It's a focused reset rather than a long-term dietary plan.

Interestingly, no one ever seems to bat an eye about the term "egg fast" or "sardine fast," yet the oatmeal fast unleashed quite a debate. Understand, it's just a figure of speech. Time to move on. I'll keep calling it a fast—because that's exactly how I see it.

Why the Oatmeal Fast?

I first heard about the oatmeal fast at a Keto Retreat in Austria organized by Mag. Julia Tulipan, MSc und Daniela Pfeifer. Yes, I was skeptical. I asked them if this was for real. To my surprise, the concept wasn't some trendy gimmick. It's based on science and even has historical roots. Dr. Carl von Noorden, a German physician and one of the earliest advocates of very-low-carb diets for diabetes, developed the oatmeal cure as a short-term intervention to improve blood sugar and metabolic health. It wasn't meant to replace a very-low-carb diet but to complement it as another tool in the box. Occasional that is.

Again, and I feel this needs to be repeated, the oatmeal fast is not a diet. I am not on a mission to make oatmeal a keto staple.

Dr. von Noorden developed the oatmeal fast about 100 years ago. Here's a link to a more recent study.

The oatmeal fast intrigued me. It's not about stuffing down carbs down my neck, but about leveraging a specific protocol for metabolic reset. I explained the potential benefits in my earlier blog (Original Post).

My Protocol
  • Two meals of steel-cut organic oats, a total of 220g, sprinkled with some cinnamon, two drops of Monkfruit, and soaked for about 10 minutes in boiling hot water, plus a teaspoon of butter.
  • To my first meal, I added an Americano with a tablespoon of heavy cream.
  • Even though the original protocol allows for some fruit, I didn't add any to my version of the oatmeal fast.
Macros (via Carb Manager):
  • Calories: 944
  • Fat: 27g
  • Net Carbs: 127g
  • Protein: 28g
Expectations vs. Reality

1. Ketosis: One of my avid critics predicted I would no longer be in ketosis. I agreed that the carbs would kick me out of ketosis entirely. While I wasn't in ketosis immediately after meals (when glucose spiked), I measured ketones before meals. On day 1, I saw 0.2 mmol/L (1.8 mg/dL); by day 3, it had climbed to 0.5 mmol/L (4.5 mg/dL). My metabolic flexibility was intact.


2. Fat-Adaptation: The same critic explained I would also no longer stay fat-adapted. This, of course, was wrong. Fat adaptation is not something we drop in and out of. It's a metabolic flex that I didn't lose. This was confirmed because, despite eating a hypocaloric diet, I never felt hungry. Not even after an 18-hour fast. I seamlessly switched to "fat-burning" even with the introduction of carbs.

3. Hunger and Cravings: I worried the oatmeal fast might trigger carb cravings and hunger. Instead, the plain taste of oats—enhanced with just a bit of cinnamon, Monkfruit, and butter—kept meals satisfying without sparking cravings for more. For the entire oatmeal fast, I was fully satiated.

4. Glucose Spikes: Glucose spikes were expected, and they happened—but with an interesting twist. On day 1, my post-meal glucose spiked to nearly 12 mmol/L (216 mg/dL), but by day 3, the peak had dropped to around 9 mmol/L (162 mg/dL). Even better, glucose consistently returned to baseline (around 5.5 mmol/L or 99 mg/dL) within two hours. By the end, my baseline glucose had trended downward overall.

For context, a little over 5 years ago, I was an insulin dependent type 2 diabetic, also on a high dose of Metformin. All that with very poor control. My A1c was at 8.5%. 7 months into keto, I no longer needed insulin or Metformin, and my A1c averaged 5.2% since.


5. Reactive Hypoglycemia: One major concern was reactive hypoglycemia. My pancreas, accustomed to minimal or zero carbs, might overcompensate and cause my blood sugar to crash. However, this never happened. My glucose remained stable, not having any hypos.

6. Digestive Comfort: Switching from an mostly meat diet to an all-oatmeal diet could have wreaked havoc on my digestion, but it didn't. I experienced no bloating, discomfort, or changes in bathroom habits. Another surprise!

Labs and Results
Test Before Oatmeal Fast After Oatmeal Fast Units Normal Range Comments
Total Cholesterol 282 231 mg/dL <200 mg/dL A significant drop likely due to carbohydrate intake after keto.
HDL 57 43 mg/dL ≥40 mg/dL Expected decrease due to reduced omega-3 intake.
LDL 187 147 mg/dL <100 mg/dL Drop aligns with effects of carb inclusion after keto.
Triglycerides 140 164 mg/dL <150 mg/dL Increase consistent with low-calorie interventions.
Insulin 20.1 18 mIU/L <25 mIU/L Improved sensitivity, considering a coinciding drop of glucose baseline.

The lab results showed some expected changes due to the oatmeal fast. The significant drop in total cholesterol, from 282 mg/dL to 231 mg/dL, aligns with the effects of carbohydrate inclusion after keto, which typically reduces LDL and total cholesterol levels. However, HDL also dropped from 57 mg/dL to 43 mg/dL, which was expected due to the absence of omega-3-rich foods like fatty fish and beef during the fast.

Triglycerides increased slightly from 140 mg/dL to 164 mg/dL, a known effect of low-calorie diets and metabolic adjustments. My trigs tend to be in the high range despite eating close to no carbs. I think this may be related to my dysfuncgtional thyroid. Insulin levels decreased from 20.1 mIU/L to 18 mIU/L, indicating improved insulin sensitivity, because baseline glucose levels were also lower. It's worth noting that the German lab results showed much higher insulin levels compared to my LabCorp’s tests in the recent past (typically around 10 mIU/L).

Weight Loss

One of the outcomes of the oatmeal fast was a noticeable change in my weight. I lost 4.4 pounds during the fast (5 days), which I fully understand is mostly water weight. What surprised me, however, was that I regained only 1 pound after returning to my regular diet—ketovore. This suggests that the fast may have contributed to more than just temporary changes, potentially resetting aspects of my metabolism or reducing inflammation. While weight loss wasn't my primary goal, it's an encouraging side benefit worth noting.

What Surprised Me Most

The biggest shock was how good I felt. No, not a sugar rush from the glucose in oatmeal. I didn't expect my baseline glucose to trend downward. I didn't expect satiety levels comparable to keto or carnivore. And I certainly didn't expect to somewhat get back into ketosis between meals. But the results were clear: my body responded well to this short-term intervention.

Bonus Surprise: A Lasting Effect

A surprising benefit of the oatmeal fast revealed itself on my flight back home. I enjoyed a variety of higher-carb meals: Labskaus (a traditional dish with corned beef, potatoes, and beetroot, served with pickled herring), beef with mashed potatoes and fruit, and later, fish with even more fruit. To my amazement, my blood sugar barely budged. Despite consuming about 30g of carbs in meals 2 and 3, my glucose levels remained stable, rising only a little. Not even a spike. This unexpected outcome hinted at a lasting effect of the fast—greater metabolic flexibility and the ability to eat some fruit without the dramatic blood sugar surges often experienced by keto folks. The images of my meals and glucose levels tell the story better than words ever could. For context, the tiny apple symbols at the top of the chart indicate the time of each meal.


Lessons Learned
  • Be Open-Minded: Nutrition isn't one-size-fits-all, and no single approach has all the answers.
  • Avoid Dogma: Whether you're keto, carnivore, vegan, or anything else, don't let rigidity blind you to other possibilities.
  • Metabolic Flexibility Matters: Being fat-adapted allowed me to navigate this experiment without hunger or cravings.
  • Science > Bias: The oatmeal fast isn't about binging carbs; it's a strategic, science-backed intervention.
Final Thoughts

I ventured outside the keto echo chamber, and it paid off. The oatmeal fast wasn't just a metabolic reset—it was a reminder that there's always more to learn. My hope is that this inspires others to explore nutrition with curiosity rather than dogma. The body is adaptable, and the right tools can unlock incredible potential.

To the doubters: I don't enjoy saying, "I told you so"—but this time, I kind of do. Stay curious and don't let bias blind you.

Written by Roxana Soetebeer, MHP, PHC
Published January 18th, 2025

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