Water and Drinks: What to Sip and What to Skip

The short version

There's no magic number. Most healthy adults do fine by drinking when thirsty and aiming for pale yellow urine.
Cutting liquid calories is one of the easiest ways to lose weight.
Drinking water before meals may help a little, especially in older adults.
Up to about 400 mg of caffeine a day is generally considered safe for healthy adults.

How much do you need?

US reference values suggest about 2.7 liters of total water per day for women and 3.7 liters for men, including water from food, which often provides about 20%. That doesn't mean you need to force eight glasses. Needs vary widely depending on your size, activity and climate.

Simple signs you're getting enough:

You rarely feel thirsty.
Your urine is pale yellow.

Coffee and tea count. The mild diuretic effect doesn't undo the fluid you're drinking.

Does water help you lose weight?

A little, maybe. In one small trial, older adults on a diet who drank about 2 cups of water before each meal lost about 44% more weight over 12 weeks than those who didn't. It's worth trying, since it's free. But the main effect of water is simply replacing higher-calorie drinks.

Liquid calories add up

Drinks don't fill you up the way food does, so people tend not to eat less to make up for them.

Drink	Approx. calories
12 oz soda	150
16 oz sweetened iced tea	120 to 180
8 oz orange juice	110
Large smoothie	300 to 600+
16 oz flavored latte with whole milk	250 to 400+
20 oz sports drink	130 to 150
12 oz regular beer	150
5 oz wine	120
Margarita	250 to 500+
Water, seltzer, black coffee, plain tea	0

If you drink two sodas a day and switch to seltzer, you've saved around 300 calories a day without changing a single meal.

Your best drinks

Water and seltzer. Add lemon, lime, cucumber or mint if plain gets boring.
Coffee and tea. Unsweetened or lightly sweetened.
Milk or unsweetened plant milk. Count them as food, not as a drink you can have without limit.
Diet soda. Better than regular soda, and a fine stepping stone. See sweeteners.
Juice. Small glasses, if at all. Whole fruit is much better.

Caffeine

The FDA says up to about 400 mg a day isn't generally linked to negative effects in healthy adults, or about two to three 12-ounce cups of coffee. Energy drinks and large coffee-shop cups can contain much more. Caffeine after mid-afternoon can hurt your sleep. If you're pregnant or have a heart condition, ask about lower limits.

Can you drink too much water?

Yes, though it's rare. Very large amounts over a short time can dilute your blood sodium to dangerous levels. Endurance athletes and people in water-drinking contests are most at risk. Don't try to drink many liters in a few hours.

Sources

This guide is general information, not medical advice. Please check with a clinician before making big changes, especially if you have a health condition, take medication, or are pregnant. Read the full disclaimer.