Eat Stop Eat 24-Hour Dinner-to-Dinner Fasting Schedule Formula: 5 Weekly Caloric Deficit & Autophagy Window Calculations

1. Calculation 1: The Dinner-to-Dinner 24-Hour Clock Window Formula

As practitioners frequently discuss in r/intermittentfasting once-weekly 24-hour fast threads and 16:8 vs 24-hour fasting comparisons, attempting a midnight-to-midnight fast fails psychologically because going to sleep on an empty stomach elevates evening cortisol and orexin (wakefulness) signaling. By anchoring the fast to the final forkful of dinner at timestamp \( t_{\text{end,Day 1}} \) and breaking it at \( t_{\text{break,Day 2}} = t_{\text{end,Day 1}} + 24.0\text{ hrs} \), your total fasting window \( \Delta t_{\text{fast}} \) spans:

To prevent your dinner time from creeping later each week (for example, finishing dinner at \( 7:00\text{ PM} \) on Monday, starting your Tuesday dinner at \( 7:00\text{ PM} \), and finishing at \( 7:45\text{ PM} \)), most experienced practitioners apply the 23:1 Practical Anchor: close Monday's eating window at \( 7:00\text{ PM} \), fast for \( 23.0\text{ hours} \), and sit down to eat Tuesday's dinner from \( 6:00\text{ PM} \) to \( 7:00\text{ PM} \).

2. Calculation 2 & 3: Net Weekly Caloric Deficit & Post-Fast Hyperphagia Compensation

Why doesn't a 24-hour fast eliminate \( 100\% \) of a full day's Total Daily Energy Expenditure (\( \text{TDEE} \))? Because on your fasting day (e.g., Tuesday), you still eat your normal evening dinner at \( 7:00\text{ PM} \). Let \( \text{TDEE} \) represent your maintenance daily intake, \( N_{\text{fast}} \in \{1, 2\} \) represent the number of 24-hour fasts per week, \( f_{\text{dinner}} \approx 0.38 \) represent the fraction of daily calories normally consumed at dinner, and \( \alpha_{\text{comp}} \approx 0.10\text{ to } 0.15 \) represent unintentional portion expansion at the break-fast meal. Your True Net Weekly Caloric Deficit (\( \Delta E_{\text{week}} \)) is:

For an adult with a maintenance \( \text{TDEE} = 2{,}400\text{ kcal/day} \) where dinner normally provides \( 38\% \) of daily energy (\( 912\text{ kcal} \)) and the break-fast dinner expands by \( +12\% \) (\( 1{,}021\text{ kcal} \)), each 24-hour dinner-to-dinner fast eliminates exactly \( 2{,}400 - 1{,}021 = \mathbf{1{,}379\text{ kcal}} \) (or \( \mathbf{1{,}680\text{ kcal}} \) if dinner is held strictly at \( 700\text{ kcal} \)). Performing two non-consecutive 24-hour fasts per week (Monday-to-Tuesday and Thursday-to-Friday, as modeled in r/intermittentfasting 2x weekly 24-hour schedules) creates a sustainable \( 2{,}758\text{ to } 3{,}360\text{ kcal/week} \) deficit—equivalent to \( 0.79 \) to \( 0.96\text{ lbs} \) of pure adipose tissue mobilization per week while eating completely at maintenance on the other 5 days.

3. Calculation 4: Hepatic Glycogen Depletion & Lipolysis Transition Curve

During a standard 16:8 schedule, the body spends hours \( 0 \) through \( 12 \) digesting exogenous nutrients and drawing down roughly \( 60\% \) of its \( 90\text{ g} \) to \( 110\text{ g} \) liver glycogen reserve (\( \approx 360\text{ to } 440\text{ kcal} \)). Extending the fast from hour \( 16 \) to hour \( 24 \) forces liver glycogen depletion past \( 85\% \), dropping circulating plasma insulin to baseline nadir levels and accelerating free fatty acid (FFA) oxidation and ketone body (\(\beta\text{-hydroxybutyrate}\)) synthesis from \( 0.2\text{ mmol/L} \) at hour 12 up to \( 0.8 - 1.4\text{ mmol/L} \) by hour 24.

4. Calculation 5: Lean Mass Preservation & Resistance Training Pairing

Brad Pilon's core rule for Eat Stop Eat is pairing your 2 weekly fasts with \( 2 \) to \( 3 \) weekly resistance training sessions and hitting an adequate weekly protein floor so weight loss comes \( 100\% \) from fat mass rather than skeletal muscle. Across a 7-day cycle where you eat \( 15 \) total meals instead of \( 21 \) (skipping \( 4 \) daytime meals across two 24-hour fasts), your Per-Meal Protein Target (\( P_{\text{meal}} \)) for body weight \( W_{\text{kg}} \) is:

For an \( 80\text{ kg} \) (\( 176\text{ lb} \)) individual targeting \( 128\text{ g/day} \) (\( 896\text{ g/week} \)) of protein, each of your \( 15 \) weekly meals should deliver approximately \( 42\text{ g to } 45\text{ g} \) of complete leucine-rich protein (plus a \( 20\text{ g} \) high-protein snack on non-fasting days), and you should supplement \( 1{,}500\text{ mg} \) to \( 2{,}000\text{ mg} \) of sodium (electrolyte water or pink salt) plus \( 300\text{ mg} \) of magnesium during hours \( 12 \) to \( 24 \) of each fast.

5. Recommended Fasting Electrolytes & Metabolic Tracking Tools

• LMNT Raw Unflavored Zero-Sugar Electrolyte Packets (1,000mg Sodium, 200mg Potassium, 60mg Magnesium) — Zero calories and zero sweeteners to prevent cephalic-phase insulin spikes during hours 12–24.
• Keto-Mojo / Keto-BM Blood Ketone & Glucose Monitoring Kit — Verify your Glucose Ketone Index (GKI) and \(\beta\text{-hydroxybutyrate}\) transition at hour 20 to 24.
• Eat Stop Eat: The Flexible Periodic Fasting Guide — Reference protocol for combining non-consecutive 24-hour fasts with strength training.