Why I Decided to Fast in January
Fasting has always intrigued me. Not just the idea of skipping meals, but the science behind what happens when you do—and how it could help balance hormones, improve brain function, upgrade your microbiome and reset your metabolism.
So, this January, fresh off the festive season and straight into a new year (with my birthday on the 4th—timing, eh?), I dove headfirst into a self-led fasting and keto experiment. What followed was part curiosity, part biohacking, and a whole lot of learning.
Here’s the full story, including the highs, the headaches, and how this experience inspired me to create a practical program for anyone wanting to explore fasting in a sustainable, informed way.
The Set-Up: No Prep, Just Curiosity
Let’s just say I didn’t exactly ease into it. January 4th was my birthday (read: celebration, cake, and no preparation whatsoever), so on January 5th, I started cold turkey.
My goal wasn’t weight loss per se—I wanted to better understand my body’s response to different fasting methods, measure ketones and blood glucose with a simple monitor, and draw inspiration from resources like Fast Like a Girl by Dr Mindy Pelz, Dr Datis Kharrazian’s insights on metabolic types of fasting, and Metabolic Freedom by Ben Azadi.
I really enjoyed both Fast Like a Girl and Metabolic Freedom books. They inspired me to dig deeper into fasting and learn more. From my experience in clinical practice I'd found intermittent fasting worked well for lots of men that just found it easy to skip breakfast but that women struggled to maintain intermittent fasting and it's benefits. This is perhaps because women need certain tweaks and need to find their own ideal fasting method.
Intermittent fasting wasn't something I'd taught, just something I'd listened to with client's experiences. I still love the 3 meals a day that Metabolic Balance teaches but have now found ways to incorporate different types of fasting into the maintenance phase for the additional health benefits.
My aim wasn’t just physical—it was about listening to my body, tracking real-time data, and testing what I’d been learning. Armed with a blood glucose and ketone monitor, I began.
Day-by-Day Breakdown of My 7-Day Fasting & Keto Experiment
Day 1 (Jan 5): Diving In
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Weight: 55.15kg. I don't usually share my weight as it isn't helpful. I'm a small frame with naturally fairly low muscle mass so my weight is lower than many people of my height and age. However, it is one of the key markers of this experiment so I've included it.
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Food: Mainly water, plus a cup of Dad’s homemade chicken and veg broth at lunch and some beef bone broth at dinner for Fenwick but I just stuck with water. About 2.5L of water throughout the day.
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Extras: Added electrolytes—my go-to is the Keto Cocktail (thanks Ben Azadi!) with apple cider vinegar, cream of tartar, and sea salt. We (hubby was also dragged along on this experiment as well) also had black coffee. Because there was no lead in I'd have struggled with coffee withdrawal headaches so this was a definite this time round.
No ketone or glucose readings yet—I was just finding my rhythm and to be honest forgot to do them.
Day 2 (Jan 6): Headaches & Learning the Limits
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Weight: 54.4kg
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Keto: 0.5 mmol/L (just in ketosis)
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Blood glucose: 4.7 mmol/L
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BP: 97/65 (super low but my blood pressure is often around this so I wasn't concerned but I did need to keep an eye on it).
This was when things got real. I woke with a headache and low energy—classic signs of electrolyte imbalance and carb withdrawal. I tried to push through with black coffee and more electrolytes, but by lunchtime, I had to give in as had client calls all afternoon. I ate 2 eggs, some avo, celery and radish. Relief.
In hindsight? I could’ve had half that and been fine. It reminded me of what Dr Kharrazian teaches: fasting isn’t about pushing your body to extremes—it’s about listening to its signals. Next time I do this experiment it will be on non-work days!
Day 3 (Jan 7): Deeper Ketosis, Brain Fog
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Weight: 53.8kg
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Keto: Morning 4.4 mmol/L
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Blood glucose: Dropped to 3.1 mmol/L
- BP: 94/59 getting a but low even for me so had salty cashew and some electrolytes
Woke up light-headed again and had a few cashews which helped. Then came the coffee. Still felt sluggish, so I ate a light keto style lunch again to stay functional for work calls. I noticed a pattern: I had no hunger in the mornings, but when my brain needed to switch on for work, food was essential. It was then easy to skip dinner.
Dr Mindy Pelz often talks about “intuitive fasting”—especially for women. We’re not meant to fast like men (or machines). Hormones fluctuate, and so should our fasting windows.
Day 4 (Jan 8): In Ketosis & Feeling Good
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Weight: 53.05kg
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Keto: 2.6 mmol/L
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Blood glucose: 4.3 mmol/L
Now that I was eating low carb but higher fat, I stayed in ketosis and felt great. Perhaps I'd better with shorter fasts and resetting with Keto for a few days. Breakfast was my go-to: eggs, goat’s cheese, avo on paleo bread, plus almond milk coffee.
Dinner out with friends that we'd organised previously—a test of willpower. My husband had beer and pizza, this is the exact example I've given over the years on how not to come off a detox never mind a water fast, but hey he completed the fast without any food and felt his commitment to my cause was done. I had water and salad. Not exactly textbook “how to break a fast,” but I was experimenting with no rules, just observing. Refeeding properly matters, something both Metabolic Freedom and Fast Like a Girl highlight. We'll both do it differently next time.
Day 5-7 (Jan 9–11): Transitioning Gently
I stayed in ketosis for a few more days, even while reintroducing fruit and slightly higher carb meals. My body responded well, and I felt energised, grounded, and focused. By January 11th, I was out of ketosis, but I’d learned what my body needed—and how powerful fasting could be when done properly.
Top 5 Lessons I Learned From My Fasting & Keto Week
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There’s No One-Size-Fits-All Fast
Dr Datis Kharrazian breaks fasting into metabolic types. I learned I thrive on an one meal a day when I need a reset and occasional 24-hour fasts with good prep—not longer extremes. -
Women Should Fast With Their Cycle
Dr Mindy Pelz’s advice about adjusting fasting windows around your cycle made so much sense. Don’t ignore the luteal phase! Even though I'm in my 50's I still have a natural cycle and the fast just happened to fall in my follicular phase. Next time I'll ensure it does. -
Track What Matters, But Keep It Simple
A basic ketone/glucose monitor taught me when I was truly in ketosis and helped me spot when I needed fuel. For me recording my blood pressure was also necessary as I have low blood pressure to start with. -
Food Quality & Electrolytes Are Key
Bone broths and plenty of water kept me going. Electrolytes were a game-changer—especially when symptoms popped up. -
It’s Not About Restriction—It’s About Rhythm
This wasn’t punishment. It was a way to reset and reconnect with my hunger cues after the more indulgent holiday period.
Introducing My New Flexible Fasting Program
After this experiment and speaking to lots of you, I realised how many people want to fast but aren’t sure where to start—or have tried and felt awful.
That’s why I’m creating Flexible Fasting: a practical, hormone-informed, science-backed program that makes fasting work for you.
Program will include:
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The 6 fasting types (based on Dr Kharrazian's work)
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Hormone-aware fasting for women (Dr Pelz-style!)
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Refeeding guidance for energy & gut health
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Simple tracking—no fancy tech needed
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Delicious, nourishing recipes & schedules
Whether you’re a curious beginner or an intermittent faster wanting more structure, you’ll learn how to fast intuitively and sustainably.
Final Thoughts: Fasting That Adapts With You
Data gave me the numbers—but my body gave me the truth.
Fatigue, brain fog, low blood pressure—those signals mattered more than my ketone readings. A small keto meal did more for my clarity than pushing through just to “complete the fast.”
This isn’t about following rigid rules. It’s about learning your rhythm, listening closely, and adjusting as you go. That’s the difference between forcing a fast and using fasting as a tool for health.
I didn’t feel empowered because I fasted perfectly—I felt empowered because I understood what my body needed.
Now, I’m creating a program to help you do the same—with structure, flexibility, and a whole lot more self-trust.
