Nutrition
As of 2026-04-24
How Macro Cycling Calculator works
Methodology for the Macro Cycling Calculator: formulas, coefficients, data sources, assumptions, and known limitations.
Scope
Creates separate macro targets for training days and rest days, implementing carb cycling around workouts.
Formula
training_day_carbs = base_carbs + carb_shift. rest_day_carbs = base_carbs - carb_shift. Average across week = original calorie target.
Coefficients
| Parameter | Value | Note |
|---|---|---|
| Typical carb shift | +50–100 g on training days, -50–100 g on rest days | |
| Fat shifts inversely | to keep weekly calories constant |
Data sources
- Ivy JL. Regulation of muscle glycogen repletion, muscle protein synthesis and repair following exercise. J Sports Sci Med. 2004;3(3):131-138. — PMID 24482590.
- Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29 Suppl 1:S17-S27. — PMID 21660838. Source of the pre/post-training carb guidance.
- Impey SG, Hearris MA, Hammond KM, et al. Fuel for the work required: a theoretical framework for carbohydrate periodization and the glycogen threshold hypothesis. Sports Med. 2018;48(5):1031-1048. — PMID 29453741. Underpins the training-day vs rest-day carb split.
Assumptions
- Protein is held constant across both day types; fat and carb shift inversely.
Approximation range
Weekly calorie average is unchanged; cycling is a distribution, not a deficit.
Limitations
- Individual response varies — some lifters feel no difference between cycled and flat macros.
- Not appropriate during hypocaloric phases for lifters who need stable mental energy day-to-day.
Reproducibility
Base 250 g carbs, shift +75 g. Training day: 325 g carbs, -33 g fat. Rest day: 175 g carbs, +33 g fat.
Change log
- 2026-04-24: methodology page first published.
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