How to Use This System
The Black Iron Macro Calculator is your engine. Run it three times, record your numbers, and you have your entire year mapped out.
How to Use FuelPath
You don't need to calculate everything upfront. Just figure out where you are, get your numbers, and start. This system works because it meets you where you are — not where you think you should be.
Find Your Current Phase
Look at the calendar. What month is it? That tells you which phase you're in. January–March is Maintain. April–June is Cut. July–September is Maintain. October–December is Build. Starting mid-phase? That's fine — jump in where you are.
Calculate Your Macros
Use the calculator below. Enter your stats and set the goal to match your current phase. That's it — those are your numbers until the next phase transition.
Follow the Phase Guide
Read the chapter for your current phase. It tells you exactly what to expect, how to train, and what to watch for. When your phase ends, recalculate and move to the next one.
Macro Calculator
Enter your details, then change the goal setting to generate your numbers for each phase.
Your Macro Targets
This isn't a 12-week fix. It's a system you'll use for years. Every phase builds on the last. Trust the process and stay consistent — the results compound over time.
When to Recalculate
Your numbers aren't permanent. Your body changes throughout the year, and your macros should change with it. Recalculate at these key moments.
At Every Phase Transition
When you move from one phase to the next, rerun the calculator with your current weight. Your body has changed — your numbers should too.
If Your Weight Changes by More Than 10 lbs
A significant weight change within a single phase means your TDEE has shifted. Update your inputs in the calculator to keep your targets accurate.
If Your Activity Level Changes Significantly
Starting or stopping a training program, changing jobs from desk to active, or any major lifestyle shift warrants a recalculation.
The Golden Rules
Regardless of which phase you're in, these four principles apply every single day of the year.
Protein is King
In every phase, hit your protein target first. It's the most important macro for body composition, recovery, and satiety. Build your day around protein and fill in carbs and fats around it.
Consistency Beats Perfection
Hitting your macros 80–90% of the time will get you better results than hitting them perfectly for two weeks and then quitting. This is a lifestyle, not a sentence.
Trust the Phases
You will feel tempted to extend your cut or skip the build. Don't. The system works because each phase sets up the next one. Cutting too long tanks your metabolism. Skipping the build limits what your next cut can reveal.
Track, Don't Obsess
Use a food tracking app to log your intake. Weigh yourself consistently — same time, same conditions. But don't let the numbers run your life. The scale is one data point, not a verdict.
Explore Each Phase
Now that you have your numbers, explore the complete guide for each phase of your year.
Ready to Start?
Get FuelPath and take control of your nutrition year-round.
Get FuelPathFounding Member pricing. Limited spots.