There’s no shortage of information online about intermittent fasting.
There’s no shortage of advice about plant-based diets.
And there’s certainly no shortage of opinions on athletic performance.
But combine all three?
Very little exists that explores plant-based eating, advanced intermittent fasting, and structured performance training together, in a measured way.
This is my structured experiment combining plant-based nutrition, intermittent fasting, and athletic performance training.
Seven years into plant-based eating, I realised something uncomfortable.
I still couldn’t clearly explain what my own body was doing, despite training consistently,
fasting consistently for over 3 years, and eating a clean, whole-food diet.
Discipline wasn’t the issue, but I was experiencing:
Persistent bloated belly
Inconsistent morning scale weight swings
Uncertainty about food timing and physical appearance
Confusion around whether carbs, fibre, salt, or fat were responsible
Performance plateauing despite effort
There was an uncomfortable tension:
I was doing all the “right” things, but I couldn’t explain cause and effect.
And that really started to frustrate me.
By profession, I work in UX and Conversion Rate Optimisation (CRO).
At its core, CRO is simple:
You don’t guess.
You test.
You form a hypothesis.
You control variables.
You measure outcomes.
You iterate.
It struck me one evening:
What if I stopped consuming more nutrition advice, and instead applied structured experimentation to myself?
That was the start of what became Beyond 20:4.
Most intermittent fasting content lives in the 16:8 world (16 hours off: 8 hour eating window).
I’d moved well beyond that.
After gradually extending fasting windows over time, I was operating around a 20:4 structure, and eventually began testing 48-hour fasts within a training routine.
But I wasn’t measuring anything properly.
And without measurement, progress (and slippage) is very hard to quantify.
So I began systematically tracking:
Weight (daily)
Waist circumference
Relaxed belly vs tensed belly
Training sessions
Food composition
Sodium timing
Fibre density
Water and alcohol
Subjective hunger signals
Some observations were immediate.
Scale weight fluctuated dramatically based on sodium timing, processed carbs and alcohol (more on that another time).
Evening fibre affected next-morning appearance.
High-oil plant-based meals (which had previously been common) seemed to prolong bloating more than carbohydrate intake did.
Fasted runs did not reduce performance and in some cases, they improved pacing discipline.
As there is in CRO, the data revealed patterns that allowed me to stop guessing and identify where choices were sabotaging progress, and taught lessons to improve future performance.
A few things genuinely challenged assumptions.
Extended fasting did not erode strength when the refeed structure was deliberate, and limited.
I removed added oils entirely during Phase 1.
What changed wasn’t dramatic, but abdominal consistency became more predictable.
Whether that relates to overall fat density, digestive load, or my own genetic predisposition is still something I’m exploring.
Electrolytes were less important than sodium timing in isolation.
Without understanding how foods influence my body, the best of intentions often back-fired.
Protein timing, particularly in later phases, appeared more influential than simply chasing total daily grams.
And perhaps most interestingly:
Performance sometimes improved when eating less frequently, not more.
Assuming “plant-based” automatically meant optimised. It turns out that plant-based doesn’t automatically mean performance-optimised. (I've learnt a lot about plant-based performance nutrition, which I will share insights into another time).
Large fibre-heavy meals, late evening sugar, when clean carbs and protein had already filled glycogen stores, high-fat “healthy” meals (like nut dense overnight oats for example), that felt virtuous, but behaved differently physiologically.
Cutting out salt completely when layering physical exertion sessions.
Gradually, patterns formed.
Feeding before fasting, and after (refeeds), became structured rather than reactive.
Carbohydrates were specifically chosen around performance sessions (as some work better than others)... as were salt doses.
I began to understand the nutrient load in different food types, and structure my meals differently to give my body what it really needed - as opposed to vegetable bulk volume.
Finding I could tie high sugar desserts to midday meals without sacrificing significant water retention the next day, AND avoiding the afternoon crash they normally caused when eaten singularly.
Strategies to avoid over-eating post fast strengthened and became second-nature.
No transformations at this point, but definitive improvements.
A downward trend in waist measurements
Predictable water fluctuation during 48-hour fasts
But after 11 weeks, stubborn fat was still clinging to my gut.
So I began to plan Phase 2, which introduced a protein focus on meals, and additional strength intensity training to surge physical development and push fat out.
Currently I'm about to enter week 15, which is week 3 of 8 in Phase 2, and exploring:
Protein density thresholds within plant-based meals
The upper limit of fasting windows alongside strength development
Sodium placement before different session intensities
Whether visible body composition can improve without increasing total calories
Where recovery ceilings begin to show
The experiment continues.
Because adaptation never stops.
What works for me may not work for you.
Your training load, hormonal profile, stress exposure, digestion patterns, sleep quality and lifestyle will all shape outcomes differently.
This is not prescription, but exploration.
The most valuable shift wasn’t dietary.
It was psychological.
Instead of reacting to scale numbers, I was able to understand and predict them based on food intake and timings. This elevation of perspective not only protected my sanity, but allowed me to forge ahead testing other variables.
What would happen if you applied structured experimentation to your nutrition instead of consuming more advice?
What would you learn about your own physiology?
That question is what continues to drive this project.
And it’s why this blog exists.
To document lived testing at the intersection of:
Plant-based eating
Advanced intermittent fasting
Athletic performance
Not as theory.
But as measured experience.
The experiment continues.