Fat Loss Formula

Macro Cycling Formula

Macro cycling matches daily carbohydrate intake to daily training demand. Hard training days get higher carbs (6-10 g/kg); easy or rest days get fewer (3-4 g/kg). Protein stays constant at 1.6-2.2 g/kg every day. Fat fills the remainder. Burke & Hawley 2018 framework reflects glycogen recovery research — chronic over-feeding carbs on rest days adds calories without benefit; under-feeding carbs on training days impairs session quality.

4 VARIABLESPublished May 14, 2026Live Content

By Orbyd Editorial · AI Fit Hub Team

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Formula 4 variables Worked example Variations

Education · Not medical advice. Output is deterministic math from your inputs.Editorial standards Sponsor disclosure Corrections

Formula

Copy the exact expression or work through it step by step below.

 carb_g_training = mass_kg × (6 to 10) g/kg
carb_g_rest    = mass_kg × (3 to 4) g/kg
protein_g       = mass_kg × (1.6 to 2.2) g/kg   [constant across days]
fat_g           = remaining calories / 9   [fat is the slack]

Variables

carb_g_training

Training-day carbs

Higher dose to fuel session glycogen needs + replace post-session loss. Range: 6 g/kg (moderate training) to 10 g/kg (multi-hour endurance days).

carb_g_rest

Rest-day carbs

Lower dose since metabolic demand is lower. Range: 3 g/kg (sedentary rest) to 4 g/kg (active recovery — walking, mobility work, easy spin).

protein_g

Protein (constant)

ISSN 2017 evidence-based range: 1.6-2.2 g/kg/day. Higher end (2.0-2.2) during fat-loss phases or for strength athletes; 1.6 for general fitness. Keep CONSTANT across training and rest days — protein protects against muscle loss most effectively when daily.

fat_g

Fat (remainder)

After protein + carbs, fat fills the remaining calories. Floor at 0.8 g/kg for hormone health (testosterone, ghrelin/leptin signaling). On hard-training days fat tends to be lower; on rest days higher.

Step By Step

1

Identify your training schedule. Categorize each day: hard training, moderate, easy/rest.

Week: Mon hard lift, Tue easy run, Wed hard lift, Thu rest, Fri hard lift, Sat moderate cardio, Sun rest. So 3 hard days, 1 moderate, 1 easy, 2 rest.
2

Set protein target. Same every day.

80 kg × 2.0 g/kg = 160 g protein/day (every day).
3

Set hard-day carb target: 6-10 g/kg based on duration/intensity.

Hard lift (60-90 min): 6 g/kg → 80 × 6 = 480 g carbs.
4

Set rest-day carb target: 3-4 g/kg.

Full rest: 3 g/kg → 80 × 3 = 240 g carbs. Easy run day: 4 g/kg = 320 g.
5

Fill remaining calories with fat. Compute total calories per day type from TDEE.

Hard lift day: 160 × 4 + 480 × 4 = 640 + 1,920 = 2,560 from P+C. TDEE 2,800. Remaining: 240 cal → 27 g fat. Rest day: 160 × 4 + 240 × 4 = 1,600 from P+C. TDEE 2,300 (no exercise). Remaining: 700 cal → 78 g fat. Compare: hard-day low fat + carb-loaded; rest-day higher fat.

Worked Example

80 kg recreational lifter, 3 hard sessions/week + 1 moderate + 1 easy + 2 rest, maintenance kcal cycle

Body mass

80 kg

TDEE hard day

2,800 kcal

TDEE rest day

2,300 kcal

Protein constant

2.0 g/kg = 160 g/day

Hard day: 160P / 480C / 27F (kcal 640+1920+243 = 2,803) Mod day (4 g/kg C): 160P / 320C / 47F (kcal 640+1280+423 = 2,343) Rest day: 160P / 240C / 78F (kcal 640+960+700 = 2,300) Weekly avg: (3×2,803 + 1×2,500 + 1×2,343 + 2×2,300) / 7 = 2,535 kcal/day

Weekly average maintenance with daily variance. Total weekly carbs: 3,200 g (vs 4,200 g if 480 carbs every day). Saved ~1,000 g carbs/week = ~4,000 fewer kcal across the week. Allows a slight surplus on hard days (supporting recovery + training quality) without exceeding weekly maintenance.

Common Variations

Train-low / sleep-low (Burke 2017): occasional sessions performed with low glycogen to trigger mitochondrial adaptation. 2-3 sessions/week max. Performance during the low-glycogen session is impaired; adaptation upside is the benefit.

Refeed / diet break (Helms 2014, MATADOR trial Byrne 2018): planned 1-2 week refeed every 4-6 weeks of dieting to restore leptin/thyroid signaling. Carbs spike to 5-6 g/kg, calories at maintenance.

Carb back-loading (Kiefer): 80% of daily carbs concentrated post-training. Not well-supported empirically — total daily carbs matters more than timing for most outcomes (Aragon & Schoenfeld 2013).

Targeted ketogenic (cyclical keto): 5-6 days ketogenic + 1-2 days high-carb. Research thin; popular among physique competitors who already have lower carb tolerance.

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Sources & References

Burke et al. (2018). Toward a common understanding of diet-exercise strategies to manipulate fuel availability for training and competition preparation in endurance sport. — International Journal of Sport Nutrition and Exercise Metabolism — periodized nutrition framework
Burke et al. (2017). Re-examining high-fat diets for sports performance: did we call the 'nail in the coffin' too soon? — Sports Medicine — train-low protocol evidence
Byrne et al. (2018). Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study. — International Journal of Obesity — diet break / refeed evidence
Aragon & Schoenfeld (2013). Nutrient timing revisited: is there a post-exercise anabolic window? — JISSN — timing vs total daily intake