Client Macro Calculator
Protein set by phase, fat to a floor, carbohydrate takes the remainder, and a fibre target most macro calculators omit entirely.
Your results
Within a personal trainer's scope: general healthy eating guidance, protein and calorie targets, and helping a client interpret their own tracking. Outside it: bespoke prescriptive meal plans, and anything involving a medical condition — those need a registered nutrition professional. Knowing where that line sits protects you and your client.
Why protein rises in a deficit
Protein requirements go up when calories come down, which is the opposite of what most diets do. Reviews of fat-loss phases in resistance-trained athletes recommend 2.3–3.1 g per kg of fat-free mass — which lands around 2.0–2.6 g/kg of body weight for a reasonably lean client.
Three reasons it matters more in a cut: it is the strongest dietary protection against muscle loss, it is the most satiating macronutrient, and it has the highest thermic effect. All three help exactly when a client needs them most.
Plant-based clients get roughly 15% more, because plant protein is lower in leucine and slightly less digestible.
The two things this calculator enforces
A fat floor at 0.5 g/kg. If the chosen percentage falls below it, fat is raised and carbohydrate reduced. Below about 15% of calories is where the evidence on low-fat diets and hormones starts to matter — and for female clients, very low fat combined with low total energy shows up as menstrual disruption rather than as a hormone number. If a client's cycle changes during a diet, that is a reason to raise calories, not to push harder.
A fibre target at roughly 14 g per 1,000 kcal. Most macro calculators ignore fibre, and dieting clients are exactly the group who benefit most: it is one of the two levers (with protein) that makes a given calorie level tolerable. It is also the thing a protein-focused diet loses by construction, since no protein source contains any.
Common questions
How much protein for a client in a deficit?
Around 2.3 g per kg of body weight, or 2.3–3.1 g per kg of fat-free mass. Higher the leaner they are.
What macro split should I prescribe?
Set protein and a fat floor, then let carbohydrate take the remainder. The exact carb-to-fat balance is largely client preference.
Should I give clients exact gram targets?
Targets and general guidance are within scope. A prescriptive meal plan built around them is not.
Why include a fibre target?
Because dieting clients need it most and protein-focused diets lose it by construction. It is one of the two levers that makes a deficit bearable.
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Track the numbers, not just calculate them
MyFitsy stores your weight, measurements and every session, so the figures above become a trend instead of a one-off.
