Macros sound complicated, but the maths is honestly GCSE level. If you can work out a tip at the pub, you can calculate your macros. Here is the calm, practical approach we use at FitNEXT, with a worked example so you can copy the method rather than faff with six different apps.
Key Takeaways
- – Estimate your TDEE using bodyweight in kg multiplied by an activity factor
- – Take a 15 to 20 percent deficit for steady fat loss, not more
- – Set protein first at 1.6g per kg of bodyweight
- – Set fat at around 0.8g per kg, then fill the rest with carbohydrate
- – Recalculate every 4 to 6 weeks as your weight changes
Step 1: Estimate your TDEE
Your Total Daily Energy Expenditure is the calories you burn in an average day. The simplest sensible estimate is bodyweight in kilograms multiplied by an activity factor.
- Desk job, little walking: bodyweight kg x 28
- On your feet, 2 to 3 gym sessions: bodyweight kg x 32
- Active job or daily training: bodyweight kg x 36
For our 80kg worked example with a desk job and three gym sessions a week, that is 80 x 32 = 2,560 kcal.
Step 2: Apply a sensible deficit
A 15 to 20 percent deficit gives roughly 0.5 to 0.7kg of loss per week without wrecking your energy, sleep or mood. Anything more aggressive and adherence collapses within a fortnight.
80kg example: 2,560 x 0.82 = 2,100 kcal (rounded). That is the daily target.
Weigh yourself three mornings a week and take the average. Single-day swings of 1kg are normal and mean nothing.
Step 3: Set protein first
Protein protects muscle in a deficit and keeps you full. The evidence-based target is 1.6g per kg of bodyweight. Our 80kg person therefore needs 128g of protein per day, which is roughly 512 kcal from protein.
If you are unsure where to get it, our practical UK protein guide breaks down the cheapest sources by supermarket.
Step 4: Set fat, then carbs
Fat should sit around 0.8g per kg for hormone health and satiety. For 80kg that is 64g of fat, or 576 kcal.
Whatever remains becomes your carbohydrate allowance:
- 2,100 kcal target minus 512 (protein) minus 576 (fat) = 1,012 kcal for carbs
- Divide by 4 to get grams: 1,012 / 4 = 253g carbs
Final split for an 80kg adult: 2,100 kcal, 128g protein, 64g fat, 253g carbs.
Step 5: Track, review, adjust
Track honestly for two weeks, weigh in three times a week, and only adjust if the four-week average has not moved. Do not slash calories further the moment the scale stalls on a Tuesday.
Pair this with strength work from our beginners strength training guide and you will hold muscle whilst the fat comes off. If the whole idea of tracking feels like too much, start with our beginner nutrition basics instead and come back to macros later.
Ready to put this into practice?
Pair your macros with a structured four-week plan.
See the first-month plan