Mr Z

AI Prompt for Body Recomposition: Free, by an 18-Year Coach

Francesco Zen, founder of ZTraining · Published 3 July 2026 · Updated 3 July 2026

The prompt

Copy-paste prompt, built from 18 years of coachingAct as my body recomposition coach, not a generic diet or bulk generator. Before giving me anything, ask me for: my height, current weight, a rough body-fat estimate, my training experience, how many days a week I can realistically train, and whether I am newer to structured training or returning after time off (recomposition works best for those two groups). Once you have that: 1. Calculate my lean body mass: weight x (1 - body fat % / 100). 2. Set my daily protein target from lean mass, not total bodyweight, using roughly 0.7-0.8g per lb of lean mass, on the higher end since protein is the priority macro for recomposition. 3. Set a daily fat target of roughly 40-50g a day, adjusted slightly for my sex and bodyweight. 4. Set calories close to maintenance rather than a clear deficit or surplus. Recomposition works through training stimulus and protein, not aggressive calorie manipulation. 5. Give me the remaining calories as carbohydrate to fuel training. Do not cut them to force faster scale movement. 6. Tell me clearly that the scale may barely move for weeks while my body composition genuinely changes, and what to track instead: waist measurement, how clothes fit, and whether my training numbers are going up. 7. Build training around the days I actually gave you, with a clear progression plan, not the same session repeated. 8. If I miss a session, adjust from where I actually am, do not make me restart. 9. Be honest about how long real recomposition takes. Do not oversell a fast result. Ask me the setup questions now, before giving me any numbers or a training structure.

Why this prompt works

Recomposition fails in most generic prompts because they only know two settings, cut or bulk, and recomposition is neither. This prompt holds calories near maintenance and pushes protein toward the higher end of what someone's lean mass and training level can justify, since protein and training stimulus, not a calorie deficit, are what actually drive the muscle-up, fat-down effect.

It also front-loads the expectation that the scale will barely move. Fat leaving and muscle arriving at similar rates can hold total weight flat for weeks while the mirror changes completely. Watching the wrong metric is the single biggest reason people abandon a recomposition that is working.

A real-world example

Take a 41-year-old returning to training after two years off: 85kg, around 24% body fat, three available days. His protein target is set high relative to his lean mass, calories held at maintenance, and the remainder given to carbohydrate across three progressive full-body sessions.

Six weeks in, the scale might show 84kg and look like failure. The waist tape showing real change and every lift up is the actual report card, and the prompt instructs the AI to say exactly that before he even starts.

Where a single prompt hits its ceiling

Recomposition is the slowest, most easily misread process in training, which makes it the worst possible match for a tool with no memory. The AI cannot notice that your waist is down and your lifts are up while the scale sat still, unless you collect all of that yourself, every time, and ask it to interpret the picture from scratch.

Without that ongoing read, the most likely failure is not a wrong plan. It is a correct plan abandoned in week six, right before the visible change tends to arrive.

Common questions

Can you build muscle and lose fat at the same time?

Yes, it is called body recomposition, and it works best for people newer to structured training or returning after a break. It runs on calories near maintenance and a high protein target, not a hard cut or bulk.

Why isn't the scale moving during body recomposition?

Because fat loss and muscle gain at similar rates can leave total weight unchanged while your body genuinely changes. Waist measurement and training performance are the reliable signals, not the scale.

How long does body recomposition take?

Longer than a straightforward cut. Real, visible change is measured in months, not weeks, which is why realistic expectations need setting before you start, not after the scale disappoints you.

Francesco Zen is the founder of ZTraining and ZLIFE, with 18 years of coaching experience working with executives across the UK, US, and UAE. He built Mr Z, an AI coach trained on his methodology to bring the same approach to a wider audience.