Let's say someone's weight is 132 lbs.
It is defined by taking the fixed numerical value of the Planck constant h to be 6.
If you weigh it, it weighs almost 25 pounds.
Prior to the current definition, the kilogram was defined as being equal to the mass of a physical prototype, a cylinder made of a platinum-iridium alloy, which was an imperfect measure.
After rounding off to two decimal places it is equal 1.
This is at least in part due to the inconsistencies and lack of coherence that can arise through use of centimeter-gram-second systems, such as those between the systems of electrostatic and electromagnetic units.