The hydrating aspects outweigh the small diuretic effect
Speaking about a day of drinking just tea and coffee, Webster said: “You’ll probably be extremely over-caffeinated!”
She continued: “When consumed in large doses – about the amount in five cups of coffee – caffeine can induce a small diuretic effect, meaning that our bodies increase urine production to remove more fluid.”
However, she said this doesn’t necessarily mean they’re less hydrating.
“The hydrating aspects of tea and coffee outweigh the minor increase in fluid offloading, so these drinks have a net positive effect on hydration,” she said.
“In addition, building up a caffeine tolerance – like what happens when your morning cup of coffee becomes your morning three cups of coffee – will lower the diuretic effect.”