Start with an appropriate daily energy estimate, choose a protein target, then work out how carbohydrate and fat fit. The calculation is a planning tool, not a guarantee of muscle gain.
First, separate resting energy from daily needs
The Mifflin–St Jeor equation estimates resting energy expenditure. It does not directly calculate everything you burn across a day. Movement, work and training add to your needs, and a calculator cannot measure those precisely.
For an introduction to estimating total intake, read how many calories you need. Avoid treating a calculator result to the nearest calorie as an exact prescription.
Choose protein, then do the arithmetic
The ISSN protein position stand suggests 1.4–2.0g/kg/day for most exercising adults. Our protein guide explains the evidence and limitations. Do not choose the highest number simply because it looks more serious.
For illustration only, imagine an 80kg adult using a 2,500kcal daily budget and 1.6g/kg of protein. That gives 128g of protein. Suppose they allocate 80g to fat; the remaining energy can be allocated to carbohydrate. These choices demonstrate the calculation, not what every 80kg person should eat.
| Macro | Amount | Energy calculation |
|---|---|---|
| Protein | 128g | 128 × 4 = 512kcal |
| Fat | 80g | 80 × 9 = 720kcal |
| Carbohydrate | 317g | (2,500 − 512 − 720) ÷ 4 |
| Total | — | 2,500kcal |
This uses the conventional approximate energy values of 4kcal per gram for protein and carbohydrate and 9 for fat. Food labels may not total perfectly from those figures because of rounding and other components such as fibre.
A spreadsheet is not the whole diet
It is possible to hit three numbers and still have an unvaried diet. Leave room for foods you enjoy and check the broader pattern against the Eatwell Guide. If tracking makes eating feel stressful, use a simpler meal routine and seek appropriate advice.
Put the calculation to practical use
- Look at a normal day before changing it. Include drinks, snacks, oils and sauces.
- Compare portions using the same basis: per serving or per 100g.
- Choose meals that fit your routine; do not assume a “bulk” label supplies your entire day’s needs.
- Review your plan with a qualified professional if you are unsure whether the energy budget is appropriate.
Munch Now shows meal-level information on the menu. It helps with food choices, but the service does not calculate an individual muscle-gain diet or promise a particular rate of progress.
Written by Munch Now for general information. Nutrition guidance is for adults and is not an individual diet plan or medical advice. Sources are linked below. For advice tailored to your health or training, speak to a registered dietitian.
Sources and further reading
See the meals, ingredients and macros before choosing your plan.
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