What Are Macronutrients?
Macronutrients are food components we need to take in daily to ensure our bodies are working properly. If you're interested in macros for weight loss or weight gain, you will be focusing primarily on the three types that produce energy:
- Proteins — build muscles and regulate metabolism and hormones. Found in meat, fish, dairy products, nuts, and beans. 1 gram = 4 kcal.
- Carbohydrates — the main energy source. Complex carbs (fruits, vegetables) keep you full longer than simple ones (white bread, sugar). 1 gram = 4 kcal.
- Fats — the most calorie-dense macro. Serve as long-term energy reserve. Found in oil, nuts, avocados. 1 gram = 9 kcal.
What Should My Macros Be?
General guidelines for daily macronutrient distribution:
- Protein: 10–35% of total calories. A common recommendation is ~0.8 g/kg of body weight per day (minimum), or up to 1.6–2.2 g/kg for active individuals.
- Carbohydrates: 45–65% of total calories. Limit simple sugars to no more than 10% of your diet.
- Fats: 20–35% of total calories. Prefer unsaturated fats (nuts, avocados, olive oil) over saturated and trans fats.
How to Use the Macronutrient Calculator
Our macro calculator uses the Mifflin-St Jeor equation to determine your Basal Metabolic Rate (BMR):
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
The BMR is then multiplied by your activity factor to get your Total Daily Energy Expenditure (TDEE) — the number of calories needed to maintain your current weight.
Activity Level Multipliers
| Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise | 1.2 |
| Slightly Active | Light exercise 1–2 days/week | 1.4 |
| Moderately Active | Moderate exercise 2–3 days/week | 1.6 |
| Very Active | Hard exercise 4–5 days/week | 1.75 |
| Extra Active | Very hard exercise / physical job 6–7 days/week | 2.0 |
| Professional Athlete | Training multiple times per day | 2.3 |
How to Calculate Macros for Weight Loss
For weight loss, the calculator applies a 500 kcal/day deficit from your TDEE (never going below 1,200 kcal). This produces an estimated weight loss of about 0.5 kg (1 lb) per week — a safe and sustainable rate.
The macro split for weight loss is set to 30% protein / 40% carbs / 30% fat to preserve muscle mass while in a caloric deficit.
What Is the IIFYM Diet?
IIFYM (If It Fits Your Macros) is a flexible dieting approach where you can eat any food as long as it fits within your daily macro targets. Rather than forbidding specific foods, IIFYM focuses on hitting your protein, carbohydrate, and fat goals each day.
Pros: Flexible, sustainable long-term, no banned foods, teaches portion control.
Cons: Requires tracking, doesn't distinguish food quality, can be time-consuming at first.
Important Disclaimer
This calculator is for informational purposes only and is not intended to serve as a substitute for medical consultation. No online tool can replace a personalized consultation with a professional dietitian. If you're planning on losing or gaining a significant amount of weight, be sure to schedule an appointment with an expert before attempting a drastic change in your eating habits.