kcal

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kg
Daily target: kcal
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grams/day
Protein
— kcal
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grams/day
Carbohydrates
— kcal
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grams/day
Fat
— kcal
Protein — %
Carbs — %
Fat — %
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Understanding macronutrients

Macronutrients — protein, carbohydrates, and fat — are the three main sources of energy in food. Each plays a distinct role in the body, and getting the right balance for your goals can significantly affect your performance, body composition, and energy levels.

Protein (4 kcal/g)

Protein is essential for building and repairing muscle tissue, supporting immune function, and producing enzymes and hormones. For most active adults, 1.6–2.2g per kg of body weight supports muscle building or preservation. During a calorie deficit, keeping protein high — up to 2.4g/kg — helps prevent lean muscle loss while fat is burned. Unlike carbohydrates and fat, protein cannot be stored as a reserve fuel, which makes consistent daily intake important.

Carbohydrates (4 kcal/g)

Carbohydrates are the body's preferred fuel source, especially for high-intensity exercise. They are stored as glycogen in muscles and the liver, providing readily available energy. Low-carb approaches can work for fat loss but typically impair high-intensity training performance. Fibre-rich whole grains, vegetables, and legumes are far preferable to refined sugars for sustained energy and metabolic health.

Fat (9 kcal/g)

Dietary fat is essential for hormone production, fat-soluble vitamin absorption (A, D, E, K), and cellular membrane integrity. Very low fat intakes — below 20% of total calories — can impair hormonal function. At 9 calories per gram compared to 4 for protein and carbs, small amounts of fat contribute significantly to total calorie intake.

How macro ratios are set

This calculator sets protein first based on body weight, then distributes remaining calories between carbohydrates and fat according to your selected goal. Fat loss goals use higher protein to preserve muscle. Muscle-building goals use higher carbs to support training intensity. Ketogenic splits set carbohydrates under 10% to promote fat adaptation. These are evidence-based starting points — individual response varies, so track your results over 4–6 weeks and adjust if needed.

Frequently asked questions

Do I need to track macros to lose weight?
No. Weight loss requires a calorie deficit regardless of macro composition. However, tracking macros — especially protein — can make hitting that deficit easier by keeping you full and preserving muscle. Many people find tracking useful for 4–8 weeks to build awareness, then transition to intuitive eating based on what they've learned.
What's the best macro split for fat loss?
High protein (1.8–2.4g/kg) with moderate carbs and fat is consistently supported by research. The exact carb-to-fat split matters less than hitting your protein target and calorie goal. A common starting point is 40% protein, 30% carbs, 30% fat — adjusted based on individual preference and activity level.
Should I eat the same macros every day?
Not necessarily. Many athletes use macro cycling — eating more carbohydrates on training days and fewer on rest days. This can improve training performance while maintaining overall calorie balance. For beginners, consistent daily targets are simpler and equally effective.
How accurate is this macro calculator?
It provides a research-based starting point. Actual needs vary based on individual metabolism, training intensity, sleep, and stress. Use the output as a starting point, track results over 3–4 weeks, and adjust by 10–15% in either direction if you're not seeing expected progress.
Not medical advice. Macro recommendations are general estimates for healthy adults. Consult a registered dietitian for personalised guidance, especially if you have diabetes, kidney disease, or other conditions affected by diet.
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