When healthy young men eat a lot of phosphate for five days, their body doesn’t change the levels of several key hormones — so scientists think a different hormone called FGF23 is the main one responding to the extra phosphate.

If healthy young men eat more phosphate-rich food for just five days, their blood phosphate levels go up—and so does a hormone called iFGF23 that helps control phosphate in the body.

When healthy young men eat a lot of phosphate, their body makes more FGF23, which seems to lower the active form of vitamin D and raise a hormone called PTH — like the body is trying to balance things out.

If young men eat a lot of phosphate for five days, their body makes less of a special hormone called Klotho that helps keep bones and kidneys healthy — so too much phosphate might quiet down this helpful hormone.

If young men eat a lot of phosphate for five days, their bodies start peeing out less calcium—probably because the phosphate and calcium stick together in the gut before they can be absorbed.