Which of the following beverages is known to act as a diuretic and can increase water loss?

Coffee acts as a diuretic primarily due to the caffeine content it contains. Caffeine stimulates the kidneys to produce more urine, leading to an increase in water loss from the body. This diuretic effect means that while coffee contributes to hydration, it can also promote the excretion of fluids.

In contrast, bottled water, juice, and milk do not typically exhibit a diuretic effect. These beverages can contribute to hydration instead of increasing urine output. Bottled water is simply a source of hydration without any diuretic properties. Juice, although high in fluids, often contains sugars which may have other physiological impacts but do not encourage diuresis. Milk also provides hydration and essential nutrients without the diuretic qualities of caffeine-containing beverages like coffee. Thus, coffee is the only option among the choices presented known for its diuretic effect, making it the correct answer.