3 Unexpected Lessons from My (Failed) High-Carbohydrate Diet Experiment

Maybe carbohydrates are not the preferred fuel after all

I am a huge fan of 30-day challenges. They are a great way to test new habits, work routines, and diet patterns.

The concept is simple. Decide to change one aspect of your life for 30 days. If you like the results, you can keep going. If you don’t like the results, you can simply drop the habit or diet.

Either way, you learn something.

I have used 30-day challenges to experiment with productivity routines and various diets. In December 2022, I embarked on a high-carb diet challenge to see if this was an eating pattern I would like.

Before The High-Carb, Low-Fat Diet Experiment

I have a long history of diet experiments. From 2006–2012 I ate a strict vegan diet. Then I switched to a strict zero-carb diet that I followed until 2015.

In the years that followed, I ate primarily low-carb with periods of ketogenic eating thrown in. In 2021, I experimented with more carbs, which I thought would help my ultrarunning performance.

However, I struggled with Irritable Bowel Syndrome (IBS) and returned to keto for a while. In March 2022, I ran the 24h German Championships on a ketogenic diet and won 2nd place in my age group.

After that, I quit keto again and included more vegetables, fruit, and starches.

Why I Decided To Try A High-Carb, Low-Fat Diet

I have been struggling with IBS since my teens. After I adopted a vegan diet in 2006 (for environmental reasons), it got progressively worse.

Eating an all-meat diet helped, but I found this way of eating hard to sustain.

After eating more carbs in 2021, my gut health worsened again, and I started to have sharp pains.

While the colonoscopy didn’t show anything to be concerned about, blood tests showed that my liver enzymes were elevated eight times above the normal range.

They have since dropped but are still slightly elevated. The liver specialist thinks I might have contracted Hepatitis in 2021 but couldn’t figure out why my liver enzymes remain elevated instead of dropping further.

So he suggested I try a low-fat diet. And since a low-fat, low-carb diet is possibly the worst thing you can do for your health, I decided to try a high-carb, low-fat diet.

Also, reports of people healing their inflammatory bowel diseases intrigued me.

If this diet could help put Crohn’s disease and Colitis Ulcerosa into remission, maybe it could also help reduce my IBS symptoms.

Perhaps the nuts and soy products in my first vegan attempt were the problems.

“Let’s give this vegan diet another try,” I thought.

What I Ate

During the first two weeks of the experiment, I focused on fruit, dried fruit, rice cakes, white rice, potatoes, and vegetables. Every now and then, I also had whole-grain bread.

Before and during my morning runs, I opted for honey.

None of these foods were a new addition to my diet. During the second half of 2022, I already included more starchy foods, fruit, and various vegetables.

The difference now was that I cut out all nuts, oils, and animal products. I tried to adhere to the guidelines of prominent vegan doctors like Neil Barnard or the team behind “Mastering Diabetes.”

However, after two weeks, I came down with a cold. I decided to eat whatever my body craved instead of adhering to a strict diet and stressing it out even more.

I trusted that my body knew better than my rational mind what it needed to heal.

I indulged in eggs, cheese, soy yogurt, bakery bread, and Tofu sausages. The rest of the month, I tried to adhere to the low-fat guidelines but ended the experiment on Christmas — a few days earlier than planned.

For one, I simply wanted to enjoy the days with my loved ones without worrying about food.

And secondly, it had already become apparent that a high-carb, low-fat diet was not for me.

What I’ve Learned

1. Choose an appropriate month for your 30-day challenge

The first lesson I learned was to avoid trying a 30-day challenge during a month when you have holiday celebrations. I didn’t think about this too much before starting, but in hindsight, it was clear that I couldn’t commit to the full 30 days.

2. Too many carbs make me sluggish

Secondly, it seems my body doesn’t like eating that many carbs. I developed a ringing in my ear that never went away during the experiment.

I was also exhausted a lot more. Even when I wasn’t sick, I slept between nine and ten hours per night and still didn’t feel fully refreshed.

Oddly, my runs didn’t feel as good, and I was less motivated to run. Especially when I had rice the day before, my morning runs felt heavy.

I also thought about food a lot more. My hunger pangs were much more intense, and I could eat massive amounts of carbohydrates and still not be satisfied. I remember having four bananas, five oranges, and 250g dried dates one night and still not feeling satiated. My tummy was full, but I was still not satisfied.

Honestly, I don’t know how fruitarians do it. But my body sure needs more protein and fat 😅.

3. My brain needs more fat and protein

And not only my body needs more protein and fat, but also my brain. Technically your brain is a part of your body, but it often gets left out of the discussion. Only a few researchers and nutritionists acknowledge that we also need to eat to nourish our brains.

And this is the final lesson I have learned during this experiment. That my brain doesn’t function well on an all-carb diet.

I was more irritable and had trouble keeping focused on work. I was also feeling more anxious.

I have been dealing with anxiety since childhood and have found ways to calm my mind and focus. Journaling, daily exercise, and meditation are three of those tools.

And it seems that avoiding eating too many carbohydrates is another.

Final Words

I admit that the setup of the experiment could have been better. I didn’t track my food, and I decided to change my eating habits during a time filled with celebrations and special treats.

However, I think the three weeks of high-carb eating have shown me that this diet isn’t for me.

Does that mean the concept is flawed? Not necessarily. Many people are thriving on a high-carb, low-fat vegan diet.

I don’t think that there is one diet that is right for everyone. And I don’t think you need to stick to one diet for the entirety of your life.

After all, our bodies change, our stress levels, and our life circumstances change.

I am learning more and more to trust my body and honor my appetite. I trust that my body knows best what it needs at any given moment.