Does cold water slow metabolism? No. It barely does anything. It’s the dietary equivalent of clapping for a change in the weather.
So drink your water however you like—cold, warm, or with a tiny umbrella in it. Your metabolism will chug along just fine, ignoring your beverage choices with majestic indifference.
Now, if you’ll excuse me, I’m off to drink a lukewarm glass of water and blame my slow metabolism on my real nemesis: Monday mornings.
Cheers (or brrr?).