Why one daily macro number isn't enough

A static macro target works for general fitness. For endurance training, it falls apart in two places: rest days look identical to hard days (so you over-eat), and the plan never adapts as your training builds (so you under-fuel as volume grows). Periodization fixes both problems by scheduling macros against the actual demands of each session.

How the engine builds your mesocycle

You enter body weight, baseline TDEE, training phase, mesocycle length, training days per week, and high-intensity days per week. The calculator returns a full week-by-week grid with five day types:

• Rest days: Calories at TDEE minus 20% carbs.
• Easy days: Z2 sessions, calories at TDEE, moderate carbs.
• Moderate days: Tempo or threshold work, +10% calories, +25% carbs.
• Hard days: Intervals or long sessions, +20% calories, +50% carbs.
• Race days: Maximum carb load (8 to 12 g/kg) and +15% calories.

Across the mesocycle, carb intake ramps progressively through base and build phases, peaks during peak phase, then drops during taper as training volume falls.

Working with the output

Treat the grid as a target band, not a precision dose. Match each day in your training calendar to the closest day type. If a session goes long or gets cut, shift the day type up or down. This is fueling at the level of training intent, not gram-counting.