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Intermittent Fasting

A practical, evidence-based introduction to intermittent fasting covering the three major protocols, hormonal and metabolic mechanisms, and a step-by-step guide to starting and troubleshooting your own fasting practice.

Adults with no prior fasting experience who want to understand the evidence behind intermittent fasting and implement a sustainable protocol safely.

Course content

Fed vs. Fasted State: What Changes and When45m
Hormones Beyond Insulin: GH, Cortisol, and Ghrelin45m
Autophagy, Cellular Repair, and the Evidence Base45m
16:8 Time-Restricted Eating: The Most Accessible Protocol45m
5:2 Protocol: Two Modified Fasting Days Per Week45m
Alternate-Day Fasting and Extended Protocols45m
The Two-Week Onramp: Gradual Window Compression45m
What to Eat in Your Eating Window45m
Exercise and Fasting: Timing, Performance, and Recovery45m

Workbook & downloads

Put the course into practice — a printable workbook plus editable templates you can fill in and reuse.

Download workbook (PDF)16 KBDownload (XLSX)8 KBDownload (XLSX)7 KB
Preview the workbook
This workbook accompanies the Intermittent Fasting course and gives you structured exercises, tracking worksheets, and planning templates to move from understanding the science to building a sustainable fasting practice. Complete each section after the corresponding course module. All tracking and planning content is general education — not medical advice; consult a qualified health professional if you have a medical condition before starting a fasting protocol.

The Science of Fasting

Ground your practice in the physiological timeline so that every decision you make about timing, food choice, and training has a mechanistic rationale behind it.
Exercise: Map Your Own Metabolic Timeline
Using the post-meal timeline from Module 1 (0–4 h absorptive, 4–8 h post-absorptive, 8–12 h early fasting, 12–18 h fasting state, 18–24 h extended fast), map where your current eating pattern lands you each day.
  1. Write down the approximate time of your last meal yesterday and your first meal today. How many hours fasted were you? Which metabolic phase does that put you in?
  2. At what time of day do you usually experience your strongest hunger? Based on the ghrelin research, what habitual meal time is conditioning that spike?
  3. Which physiological change during fasting (insulin suppression, GH pulse, glycogen depletion, autophagy) feels most relevant to your personal health goal and why?
  4. Write one if-then statement for the next morning: if I feel hungry before my target fast-break time, then I will ____.
Worksheet: Hormone and Evidence Tracker
After reading the research cited in the module, fill in this reference sheet so you have a quick lookup during your fasting practice.
  • The time window after which my liver glycogen is largely depleted (h):
  • My estimated cortisol awakening response window (approximate morning time range):
  • How long does a ghrelin wave typically last (minutes):
  • Three beverages I can drink during my fast window that will not raise insulin:
  • One fasting claim I have heard before that I now know lacks strong human evidence:
  • One evidence-backed benefit I am most interested in tracking for myself:
Checklist: Science Foundation Checklist
  • I can explain the difference between the absorptive and fasting metabolic phases
  • I understand why insulin needs to be low for fat oxidation to increase
  • I know that ghrelin spikes are habit-driven and adapt within 7–14 days
  • I can identify three beverages that are fast-safe and three that are not
  • I have noted the populations for whom fasting carries medical risk
  • I understand the difference between strong human evidence and animal-model findings

The Three Major Protocols

Compare the three core protocols against your lifestyle and select the one with the highest chance of 90-day adherence.
Exercise: Protocol Fit Assessment
Work through these prompts to arrive at a protocol recommendation for yourself. There is no universally superior protocol — adherence is the primary variable.
  1. Describe your typical daily schedule (work start time, social meal patterns, training time). Which of the three eating window structures — 16:8, 5:2, or ADF — conflicts least with that schedule?
  2. Rate your tolerance for hunger on a 1–10 scale. If under 5, note that 5:2 and ADF require more tolerance for very-low-calorie or zero-calorie days than 16:8. How does your rating affect your protocol choice?
  3. Do you have any of the contraindications listed in Lesson 3 (pregnancy, type 1 diabetes, eating disorder history, underweight BMI)? If yes, which protocol is appropriate only under medical supervision?
  4. Write a one-sentence commitment: I will follow the [protocol] protocol with a [time] eating window starting on [date].
Worksheet: Protocol Comparison Sheet
Fill in the comparison details for each protocol based on what you learned in Module 2, then circle your chosen protocol.
  • 16:8 — eating window hours I would use (e.g. noon–8 pm):
  • 16:8 — my estimated weekly calorie deficit or surplus adjustment needed:
  • 5:2 — which two days of the week I would designate as fast days:
  • 5:2 — my fast-day calorie target (500 kcal women / 600 kcal men):
  • 5:2 — two protein-forward fast-day meals I would plan:
  • ADF — reason I would or would not choose this protocol:
  • My chosen protocol and the rationale in one sentence:
Checklist: Protocol Selection Checklist
  • I have identified my preferred eating window and confirmed it fits my social and work schedule
  • I know my fast-day calorie target if using 5:2
  • I know which beverages are fast-safe and have purchased or prepared them
  • I have identified whether I have any contraindications and, if so, have noted to seek medical advice
  • I have set a start date for my chosen protocol
  • I have told at least one person in my life about my fasting window to create social accountability

Starting Your Fasting Practice

Build your two-week onramp plan, structure your eating window meals for nutritional adequacy, and position your training sessions for optimal performance and recovery.
Exercise: Two-Week Onramp Planner
Using the five-step compression approach from Module 3 Lesson 1, write out your personalised daily schedule for each phase. Be specific about times.
  1. What is your current last-meal time in the evening and your current first-meal time in the morning? Calculate your current average fasting window in hours.
  2. Write your Days 1–6 plan: what time will you close your eating window on Days 1–3, and when will you delay your first meal on Days 4–6?
  3. What will you do specifically when a hunger wave hits during the first two weeks? Describe the exact action (e.g. drink 500 ml sparkling water, set a 20-minute timer, note the time the hunger passed).
  4. How will you align your sleep timing with your fasting window to maximise the overlap between sleep hours and fasted hours?
Worksheet: Eating Window Meal Planner
Plan one full week of meals within your target eating window. Focus on protein anchors, fibre-first structure, and micronutrient coverage.
  • My target eating window (start time – end time):
  • Number of meals I will eat in the window (2 or 3):
  • My daily protein target (bodyweight in kg multiplied by 1.6–2.2 g):
  • Meal 1 (first meal) — time, protein source, carbohydrate source, vegetable, fat source:
  • Meal 2 — time, protein source, carbohydrate source, vegetable, fat source:
  • Meal 3 (optional, evening close) — time, protein source, small carb or fat:
  • Three electrolyte or micronutrient gaps I need to watch (e.g. magnesium, vitamin D, potassium):
  • My plan for addressing those gaps (food sources or supplement):
Checklist: Week 1 Launch Checklist
  • I have written my two-week window compression schedule with specific daily times
  • My kitchen is stocked with fast-safe beverages (sparkling water, black coffee, electrolyte drinks)
  • My first meal of each day is planned to be protein-rich and large enough to avoid compensatory overeating later
  • I have positioned my training session within or immediately adjacent to my eating window
  • I have a specific hunger-wave response plan written down
  • I have removed or reduced access to ultra-processed snacks that might trigger compensatory eating in the window
  • I have set a daily alarm reminding me when to close my eating window

Troubleshooting, Personalisation, and Long-Term Adherence

Diagnose problems as they arise, adapt your protocol to your biology and life phase, and build the measurement and habit systems that keep fasting sustainable past 90 days.
Exercise: Troubleshooting Log Exercise
For each common fasting obstacle, pre-plan your response so you are not making decisions under hunger or fatigue. Then use the log during your first four weeks.
  1. You wake on day 5 with a fasting headache. Based on the course, what is the most likely cause and what is the specific fix (include quantity and timing)?
  2. It is the 10th day and you are experiencing strong afternoon fatigue. Which two nutritional adjustments will you make tonight and tomorrow morning, and what is the expected timeline for the adaptation phase to pass?
  3. A social situation requires you to eat outside your window. Write a decision rule: if I need to eat outside my window for a social event, I will ____. (Hint: consider the difference between a 1-hour vs a 4-hour deviation.)
  4. After 30 days, how will you decide whether to stay on your current protocol, upgrade to 5:2 blocks, or relax to a maintenance 14:10 window? Write the criteria you will use.
Worksheet: 90-Day Progress Tracker Setup
Set up your baseline measurements before Day 1 and your tracking schedule for the first 90 days. Fill in your baseline values and target review dates.
  • Baseline date:
  • Baseline bodyweight (kg):
  • Baseline waist circumference at navel (cm):
  • Baseline resting heart rate (beats per minute, measured on waking):
  • Baseline fasting blood glucose if you have a glucometer (mg/dL or mmol/L):
  • Baseline subjective morning energy rating (1–10):
  • Baseline hunger-wave close time on a typical morning (time hunger passes without eating):
  • Week 4 review date:
  • Week 8 review date:
  • Week 12 (90-day) review date:
  • My definition of success at 90 days (one specific measurable outcome):
Checklist: Long-Term Adherence Checklist
  • I have written at least three if-then implementation intentions for common deviation triggers
  • I have recorded my baseline measurements and scheduled three review dates
  • I have identified whether I need to adjust protein targets for age or training goals
  • I have a plan for hormonal cycle phase adjustments if applicable (e.g. relaxed window in the luteal phase)
  • I know the signs that indicate I should pause fasting and consult a health professional
  • I have read about the 90-day habit automaticity timeline and set realistic expectations for the first two weeks
  • I have planned at least one intentional protocol break (holiday, illness buffer) so deviations do not feel like failures

Your Action Plan

  1. Record your current daily eating window and calculate your baseline fasting hours today
  2. Choose your target protocol (16:8, 5:2, or ADF) based on your schedule and hunger tolerance assessment from Section 2
  3. Set a start date within the next 7 days and write it down with a specific first-day eating window
  4. Stock your kitchen with fast-safe beverages: sparkling water, black coffee, and a calorie-free electrolyte powder
  5. Build your two-week compression schedule using the 5-step onramp, with specific times for each phase
  6. Plan your first three days of eating-window meals in advance, ensuring each day hits your protein target
  7. Record baseline metrics before Day 1: bodyweight, waist circumference, resting heart rate, morning energy (1–10)
  8. Write three if-then statements for your most likely failure scenarios (hunger wave, social event, fatigue crash)
  9. Schedule a Week 4 self-review to evaluate progress markers and decide whether to adjust protocol intensity
  10. Set a 90-day calendar reminder to assess full habit automaticity and re-read your Day 1 goal statement

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