Why weight is the cheapest early-warning system
Weight is the rare health signal that is objective, free to measure, and drifts early in dozens of conditions — thyroid disease, kidney disease, diabetes, dental pain, parasites, heart disease. It also drifts invisibly: living with an animal daily is the worst vantage point for noticing gradual change, which is how a cat loses fifteen percent of itself between annual visits without anyone lying. The scale sees what the eye adapts to.
Weighing dogs and cats at home
Small pets (under ~15 kg): the hold-and-subtract method — weigh yourself on a bathroom scale, weigh yourself holding the pet, subtract. Accurate enough for trend-watching, and it costs nothing.
Cats specifically: a baby scale or kitchen-style pet scale reads to 10 grams and is worth owning for cats on weight plans or seniors, where a quarter-kilogram genuinely matters.
Big dogs: the clinic walk-on scale is free at nearly every practice — walking in monthly just to weigh is normal, encouraged, and doubles as pleasant desensitization to the building.
How often is useful
- Healthy adults: monthly — frequent enough to catch drift, rare enough to sustain
- Puppies and kittens: weekly or biweekly during growth phases; the curve itself is the health record
- Seniors: biweekly to monthly — late-life conditions announce themselves here first
- On a diet or gaining plan: weekly, same day and time, so the plan gets a real feedback loop
Reading the trend like a vet would
Single readings are noise: hydration, meals, and scale differences move a reading a few percent by themselves. Trends are the signal. Percentages beat absolute numbers — half a kilogram is a rounding error on a Great Dane and a tenth of a cat. Rules of thumb worth keeping: unplanned change of five percent says pay attention, ten percent says book a visit, and in cats — where weight loss is disproportionately meaningful — treat any confirmed steady decline as vet-conversation material even under those thresholds. Speed matters as much as size: a drop over three weeks is more urgent than the same drop over a year.
Body condition: the other half of the picture
The scale cannot tell muscle from fat or say what this animal's ideal is — body condition scoring fills that gap. The home version: ribs should be feelable under a light layer without pressing, a waist should be visible from above, and a belly tuck from the side. Ribs invisible under fingers means overweight territory; ribs visible from across the room means under. Vets score this 1–9 at visits — ask where your pet lands and what number to aim for, then your scale trend has a target.
A weight log worth keeping
Four fields: date, weight, which scale, and context (post-diet-change, after illness, summer coat). Context is what makes an odd reading interpretable in a year. Keep the log where trends draw themselves — a printable weight log works on the fridge, and Pawmi charts weight entries per pet over time, puts the curve next to health notes, and refuses to blend kilograms and pounds into a fake trend, so a drifting line and its possible cause sit in the same view your vet sees.