A Change in BMI?...

Dr Ian Robinson with the NPL watt balance

NPL (National Physical Laboratory) has produced technology capable of accurate measurements of Planck's constant, which is a significant step towards changing the international definition of the kilogram – currently based on a lump of platinum-iridium metal kept in Paris, France.

I doubt it will change our BMI, but "hope springs eternal"...

NPL: One step closer to a new kilogram