Nutrition
As of 2026-04-24
How Intermittent Fasting Window Planner works
Methodology for the Intermittent Fasting Window Planner: formulas, coefficients, data sources, assumptions, and known limitations.
Scope
Picks eating and fasting windows for common protocols (16:8, 18:6, 20:4, OMAD, 5:2) and renders a 24-hour timeline.
Formula
eating_window_start = wake_time + fast_extension. eating_window_end = start + eating_window_hours.
Coefficients
| Parameter | Value | Note |
|---|---|---|
| 16:8 | 16 h fast / 8 h eat | |
| 18:6 | 18 h fast / 6 h eat | |
| 20:4 | 20 h fast / 4 h eat | |
| OMAD | ~23 h fast / 1 h eat | |
| 5:2 | 5 normal days + 2 ~500 kcal days |
Data sources
- Patterson RE, Laughlin GA, LaCroix AZ, et al. Intermittent fasting and human metabolic health. J Acad Nutr Diet. 2015;115(8):1203-1212. — PMID 25857868.
- de Cabo R, Mattson MP. Effects of intermittent fasting on health, aging, and disease. N Engl J Med. 2019;381(26):2541-2551. — PMID 31881139.
- Varady KA, Cienfuegos S, Ezpeleta M, Gabel K. Clinical application of intermittent fasting for weight loss: progress and future directions. Nat Rev Endocrinol. 2022;18(5):309-321. — PMID 35194176. Contemporary review of IF weight-loss outcomes.
Assumptions
- Total daily calories and macros are controlled; fasting schedules without calorie awareness do not automatically cause weight loss.
Approximation range
Meta-analyses find IF matches continuous calorie restriction for weight loss when calories are matched.
Limitations
- Not appropriate during pregnancy, lactation, or for people with a history of eating disorders.
- Long fasts can impair hypertrophy adaptation in lifters — protein timing still matters.
Reproducibility
Wake 7:00, 16:8 with 2 h post-wake fast extension: eating window 9:00–17:00.
Change log
- 2026-04-24: methodology page first published.
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