Final answer:
A diuretic effect occurs when caffeine intake exceeds 3 milligrams per kilogram of body weight, promoting an increase in urine output and a decrease in water conservation.
Step-by-step explanation:
A diuretic effect has been observed when caffeine consumption exceeds 3 milligrams per kilogram of body weight.
Diuretics are substances that promote the increase of urine output and reduction in water conservation by the body. Common uses for diuretics include the treatment of hypertension, congestive heart failure, and managing fluid retention. Caffeine, in particular, when consumed in large amounts, acts as a diuretic by promoting vasodilation in the nephron, leading to an increased Glomerular Filtration Rate (GFR), and also by inhibiting the Nat/Cl-symporter in the distal convoluted tubule (DCT) and collecting duct, resulting in an increased loss of sodium and water from the body.