Weight

Body mass on the scale. It combines fat, muscle, water and gut contents, which is why one reading says far less than the line through many.

Weight trends move with most metabolic markers, and a steady direction over months tells you more about your habits than any single morning.

There is no universal healthy number; what matters is your own trajectory and how it moves with the rest of your panel. Swings of a kilo or two between days are almost always water.

Worth mentioning if you are losing weight steadily without trying to.