Your body changed the rules. The math didn't.
Falling estrogen pulls muscle off your frame faster than any diet ever did — and the scale keeps lying to you about it. We raise your protein floor, hold your calories above starvation, and tell you exactly how fast you can lose without losing you.
Here's what she told the calculator.
In about two minutes, this is exactly what you'll fill in for yourself.
That's the whole input. No logging. No fasting schedule. Just who you are today and where you want to be.
Same calories. Same food. Different body.
Estrogen decline accelerates muscle loss, rewrites how you store fat, and steals the metabolic margin you used to rely on. The diet you did at 30 won't just stop working — it will actively hurt you. The math tells you what to do about it.
- A protein target that protects lean tissue.2.0–2.2 g per kg of lean body mass. Non-negotiable when estrogen is falling — hungry or not.
- A calorie floor that stops the spiral.Under 1,200 Cal and the body clings to fat, sheds muscle, and wrecks sleep. We hold the line.
- A loss-rate alarm tuned to your biology.Over 0.8% body weight per week and protein becomes urgent. We warn you before the mirror does.
The scale moves faster than your fat does.
If you've dropped 5 kg in a week before, you know the feeling. Real — but not fat. Here's what actually comes off, and in what order.
The one you want gone. 9 Cal per gram. Can't be lost faster than the math allows — about 0.5–1 kg per week at a sane deficit.
Carbs are stored with 2 g of water per gram of carb. Drop carbs, drop the water with them. Comes off in days. Goes back on in a meal.
The one you don't want gone. Lost when protein is too low or deficit is too steep. Especially at risk on GLP-1s, where appetite makes hitting protein hard.
Excess water the body holds while processing junk food. Clean up the diet, inflammation drops. Not fat, but genuinely makes you look leaner.
This is why fast-loss diets look miraculous for a week, then stall. You flushed water and glycogen — cheap to lose, cheap to put back on. Fat is the expensive one at 9,000 Cal a kilo, and the only one that actually changes how you look. The calculator above is calibrated to the expensive one.
Four steps. Three minutes. Zero fluff.
Age, height, weight. Two taps pick your activity level. Fifteen seconds.
How many kilos off. By when. No vague "feel better" targets. A number, a date.
BMR. Maintenance. Diet calories. Macros. Refeed. Eight lines. Everything.
Track in any app. MyFitnessPal, Cronometer, napkin. The number does the rest.
$7. Once. Forever.
Your numbers change as your weight does. Lifetime access means you come back, recalculate, and carry on — no resubscribing, no upsells, no funnel. One price, done.