Single-Variable Nutrition Log
Change one food variable at a time and record how your body responds
- Difficulty
- Easy
- Time to result
- ~weeks to results
- Steps
- 4
- Confidence
- 96%
Aspinall is careful to say he is not a nutrition expert and does not prescribe a universal diet. His practical method is a personal log: write down what you eat, change one thing, and record how you feel. Over time, he says this helped him identify similar foods and timings that work reliably for his body, including when he personally wants more carbohydrates around intense sessions. The useful mechanism is not the specific foods he eats; the transcript does not list them. It is reducing simultaneous changes, preserving observations in writing, and looking for repeated personal patterns rather than relying on memory. This is a routine-optimization tool, not a medical diagnostic method, and symptoms or significant dietary changes warrant appropriately qualified advice.
Origin
Extracted from The Diary of a CEO
Core principles
- 01Individual responses can differ
- 02Written observations beat vague recall
- 03Changing one variable improves interpretability
- 04Stable routines should follow repeated personal observations
How to run it
- 1
Create a baseline
Write down your food, timing, training context, and a few relevant observations such as energy or comfort.
Pro tip Use the same small set of observations each day.
Watch out Do not interpret the log as a medical diagnosis.
- 2
Change one variable
Remove, add, or retime one item while keeping other major factors as stable as practical.
Pro tip One change makes the result easier to interpret.
Watch out Avoid unsafe restriction or major dietary changes without qualified advice.
- 3
Record the response
Note how you feel and perform rather than relying on later recall.
Pro tip Include the training intensity because the same meal may feel different in a different context.
- 4
Look for repetition
Compare multiple observations and keep only patterns that recur rather than reacting to one day.
Pro tip Build a stable routine from repeated useful responses.
Watch out Seek professional advice for persistent symptoms.
In the wild
Aspinall says he wrote down what he ate, removed or added items, and noted how he felt. He now eats similar things at similar times because he has observed how his body responds.
→ He developed a repeatable personal routine rather than offering a universal diet.
A recreational athlete records lunch timing, afternoon training, energy, and stomach comfort for several days. She then changes only lunch timing and repeats the observations before deciding whether to keep it.
→ The decision is based on repeated personal observations with fewer confounding changes.
Common mistakes
Changing everything together
If foods, timing, sleep, and training all change at once, the log cannot show which variable mattered.
Turning anecdotes into prescriptions
Aspinall explicitly limits his claims to personal experience and says bodies differ.
Is it for you?
Best for
Healthy adults refining an established routine around training or daily energy.
Not ideal for
Diagnosing symptoms, treating a medical condition, or making restrictive changes without qualified guidance.
From the transcript
“Write down what you eat in a day and eliminate one thing for the next day and write how you feel.”
“Every person's body is different.”
From the episode
Tom Aspinall: The UFC Doesn't Want You To Know This! Jon Jones Wasn't Living Like An Athlete!