Macro Calculator for Protein, Carbs, and Fat Targets

What macro targets are for

Macros split a calorie target into protein, carbohydrates, and fat. They can make meal planning more concrete, especially when you are trying to keep meals steady while also thinking about IBS, SIBO, or Low FODMAP choices.

• Protein helps make meals more filling and supports muscle maintenance.
• Carbohydrates provide practical fuel for activity, training, and daily energy.
• Fat supports hormones, brain function, and absorption of fat-soluble vitamins.

How this calculator estimates macros

The calculator first estimates BMR with the Mifflin-St Jeor equation, then multiplies it by an activity factor to estimate maintenance calories. It adjusts calories for the selected goal and converts macro percentages into grams using 4 kcal per gram for protein and carbohydrates, and 9 kcal per gram for fat.

• Fat loss uses a 500 kcal reduction from estimated maintenance.
• Maintenance keeps the estimated TDEE as the calorie target.
• Muscle gain uses a 300 kcal increase from estimated maintenance.

Macro splits used by goal

The goal presets mirror common practical macro splits: higher protein during fat loss, balanced macros for maintenance, and higher carbohydrates for muscle gain or training support. They are starting points, not mandatory rules.

• Fat loss: 30% protein, 40% carbohydrates, 30% fat.
• Maintenance: 25% protein, 45% carbohydrates, 30% fat.
• Muscle gain: 25% protein, 50% carbohydrates, 25% fat.

How to use macros with digestive symptoms

Macro targets do not tell you which foods your gut tolerates. A meal can match macros and still be difficult if it contains personal triggers, large portions, or several FODMAP contributors. Treat the number as structure while food choices stay tied to tolerance and guidance.

• Familiar tolerated foods can make the estimate easier to apply.
• Macro targets should not justify overly restrictive food choices.
• Track symptoms separately from calories and macros so patterns stay clearer.

Common mistakes with macro tracking

The most common mistakes are treating the numbers as exact, choosing an activity level that is too high, cutting calories too aggressively, or changing too many foods at once. If tracking increases anxiety or restriction, use the result as a loose reference instead of a daily scorecard.