Does coffee or tea count as water intake?
The old idea that coffee and tea “dehydrate you” is mostly a myth for people who drink them regularly in moderate amounts. They count toward your daily fluid. Water is still the simplest choice.
What the NHS says
The NHS says water, lower-fat milk and lower-sugar drinks, including tea and coffee, all count as part of your daily fluid intake. It also advises having caffeine in moderation.
What the studies found
- In a 2014 study, healthy men who regularly drank coffee had four cups a day for three days and water on another three days. Researchers found no difference in hydration markers between the two (Killer et al., PLoS ONE).
- A 2016 trial compared how much of a litre of different drinks the body kept over four hours. After coffee, tea, cola and several other drinks, urine output was not different from water (Maughan et al., American Journal of Clinical Nutrition). Drinks with some milk, protein or salt were kept slightly better.
Both studies used moderate amounts in healthy adults. They do not mean every drink is the same as water.
Where caution still applies
- Alcohol increases urine output; it is not a way to stay hydrated.
- Sugary drinks add fluid, but also sugar. The NHS suggests limiting them.
- Caffeine has limits of its own. EFSA considers up to 400 mg a day safe for healthy adults (less in pregnancy). The concern there is caffeine itself, not hydration.
How Water Tracker counts
Water Tracker V1 counts plain water only, because that is the habit most people want to build. If you want coffee or tea to count toward your own goal, log them with the Other button — it is your goal and your log.
Sources
- NHS. Water, drinks and your health.
- Killer SC, Blannin AK, Jeukendrup AE (2014). No evidence of dehydration with moderate daily coffee intake. PLoS ONE 9(1):e84154.
- Maughan RJ et al. (2016). A randomized trial to assess the potential of different beverages to affect hydration status. Am J Clin Nutr 103(3):717–723.
- EFSA (2015). Scientific Opinion on the safety of caffeine. EFSA Journal 13(5):4102.
General information with sources, not medical advice.