Gravitational astrophysicists have long-since determined that Dark Energy and Dark Matter must account for over 96% of the mass of the universe, or else their pet theory would fall flat on its face.
Pioneering physiologists are now beginning to come to the conclusion that if this ratio holds true in space, then it must hold true on our scale as well. They have proposed a revised Body Mass Index that brings their theory in line with that of astrophysics. Move over water, Dark Matter and Dark Energy are the primary constituents of the body now.
Since the 1930's, astrophysicists have known that their theories had holes of cosmological proportions. The actual observations didn't fit the theory.
But, by peppering in some 'extra' mass in the form of inventive maths (dubbed Dark Matter) and some anti-gravity (dubbed Dark Energy) based on things observed not to exist, the problems were solved and plenty more problems were created to fund research through the end of the century.
Fast forward about a century, and astrophysicists have determined with high precision just how much mass is nonexistent and just how much anti-gravity effect they've invented. The ratios are around 75% Dark Energy, 21% Dark Matter and 4% actual observable reality.
"But, what about here on Earth?" asked physiologists. We have no such dilemma, which is a contradiction... So, those enterprising physiologists applied some logic to the problem and have come to the conclusion that if the universe as a whole is 75/21/4% Dark Energy/Dark Matter/Actual Observable Reality, the ratio must hold here on Earth as well.
Physicians have suggested that a new Body Mass Index should be created to demonstrate the assumed proper proportions of bodily constituents such as Dark Energy, Dark Matter, Water, Fat, Muscle, etc. No doubt the new guidelines would implicitly rewrite the rules on obesity. (Some unscrupulous hucksters, having obtained a pre-print of the research, have already begun sending around Nigerian Pharmacy SPAM preying on the gullible, assuaging their guilt over being obese and assuring them they're not really fat, per se, they've just picked up too much extra Dark Matter from eating too many Dark Energy dense foods and claiming their miracle pills will help take off the extra mass without resorting to diet, exercise or other pills.)
Applied to the human body, this means that 75% of our Body Mass must consist of Dark Energy (recalling that energy and mass are interchangeable, according to Einstein), 21% of our mass must be in the form of Dark Matter and the remaining 4% is the portion we can actually observe (water, fat, vitamins, minerals and the dime that baby Joseph just swallowed last night).
Move over water, the human body is actually mostly Dark Energy (physiologists and astrophysicists think this makes sense insofar as gravity is a strictly attractive force, thus there must be a considerable amount of Dark Energy in the body to counteract all that gravitating mass and keep us from collapsing into a singularity at any given moment in time) and a bit of Dark Matter.
By physiologists' calculations: water, previously thought to compose 55-78% of the body, now composes only 55-78% of the 'other 4%' (or approximately 2.20-3.12% of total Body Mass).
However, physiologists are confused by these results, since we can directly measure the body's total mass and the mass of just the body's water and these results are clearly contradictory. Physiologists have begun to suspect that astrophysicists are just pulling their legs.
But, refusing to believe that their chains are being yanked, a few enterprising physiologists have taken up the gauntlet not just dropped but clearly abandoned by the astrophysicists. What if, they ask, all matter (water included) is composed of 70% dark energy, 21% dark matter and only 4% actual observable matter.
But, this too poses problems, because we can very accurately measure the mass of observable particles too, which agree with existing theories of the observable world.
So, for now, the physiology world is evenly divided. Without a 'simple majority' show of hands, they can't vote dark energy and dark matter into the hallowed halls of physiology.
For now, they've decided to dump the big steaming pile of research back on the doorstep astrophysicists, in a brown paper bag, with a big yellow sticky note on it that says "Admit it! You're shitting us, right?"