Act as my fat loss coach, not a crash diet generator. Before giving me anything, ask me for: my height, current weight, a rough body-fat estimate, my activity level, how many days a week I can realistically train, what equipment I have, and how quickly I am hoping to lose weight.
Once you have that:
1. Estimate my maintenance calories from my stats and activity level, and show me how you got there.
2. Set a moderate deficit from that maintenance figure, not an aggressive one. Tell me the rate of weekly weight loss it should produce, and be honest if what I asked for is unrealistic or unsafe.
3. Work out my lean body mass from my weight and body-fat estimate, and set my protein target from that, not from my total weight. Protect protein first, and take the deficit from fat and carbohydrate.
4. Keep strength training in my week, built around the days and equipment I gave you, so I hold on to muscle while I lose fat.
5. Tell me what to track besides the scale: waist measurement, how clothes fit, and whether my training numbers are holding.
6. Tell me this deficit is not fixed. As I lose weight, maintenance drops too, so the same calorie target becomes a smaller deficit over time unless it is recalculated.
7. If I tell you progress has stalled, do not just cut calories further as the first move. Ask about training, sleep, stress and adherence before assuming the deficit itself is the problem.
8. Be direct if my expectations for speed do not match a sustainable approach.
Ask me the setup questions now, before giving me a number.
Why this prompt works
The most common fat loss mistake is not a slow deficit, it is an aggressive one that costs muscle and adherence long before it costs meaningful extra fat. A deficit that protects protein and stays moderate holds on to lean mass and training performance far better than a steep one, which is why this prompt sets protein first and takes the deficit from the remaining macros.
Maintenance calories also drop as body weight drops, so a deficit calculated once at the start quietly shrinks over a phase of several months. It is one of the most common reasons a fixed calorie target stalls, and it is often misread as a plateau in the body when the target simply needs recalculating.
A real-world example
Take someone hoping to lose 1kg a week from a starting maintenance in the low 2000s. That rate typically implies a deficit steep enough to threaten muscle and training quality, and a coach-built prompt should say so directly rather than simply computing the number requested and handing it over.
The honest answer here is usually a smaller weekly loss target with protein and training protected, which is slower but is the version that is still working in month three.
Where a single prompt hits its ceiling
Maintenance calorie estimates are exactly that, estimates, generated from formulas that carry real error margins even with accurate inputs. The number this prompt gives you is a sensible starting point, not a precise measurement, and should be adjusted based on what actually happens to your weight over the following weeks.
It also cannot diagnose a genuine stall. A plateau can come from adherence drifting, sleep or stress changing, or water retention masking real progress, and telling those apart requires watching a pattern over time, not reading one week's number.
