How many calories are in one gram of hot water?

Compromising up to 60% of the human adult body, water is vital for life.

It regulates body temperature, transports nutrients, provides structure to cells and tissues, and removes waste.

With various types of water on the market, you may wonder whether some of these products have calories.

This article discusses whether plain and other types of water contain calories and provides tips on how much water you should drink per day.

Plain water is calorie-free.

Calories come from three nutrients in your diet — carbs, fats, and proteins. Alcohol — while not considered a nutrient — contributes calories as well.

Plain water is devoid of these nutrients and thus contains no calories.

Still, it contains trace amounts of minerals, including calcium, magnesium, sodium, zinc, and copper (1).

In fact, one study found that by drinking 68 ounces (2 liters) of water per day, adults may fulfill 8–16% of their Daily Value (DV) for calcium and 6–31% of their DV for magnesium (2).

In the United States, fluoride is added to water to reduce tooth decay (3).

Summary

Plain water is calorie-free and contains traces of minerals like calcium, magnesium, sodium, zinc, and copper. In some countries, fluoride is added to reduce tooth decay.

If you don’t like the taste of plain water, you may prefer flavored or carbonated varieties.

Though some of these options are calorie-free, many contain negligible to moderate numbers of calories.

Carbonated waters

Carbonated water, also known as club soda, seltzer, sparkling, or tonic water, contains carbonic acid formed from dissolved carbon dioxide.

It’s what gives carbonated water its fizz and tang.

Carbonated waters may be plain or contain natural flavors or minerals to enhance flavor.

While these types are generally calorie-free, tonic water is often sweetened with sugar.

Thus, a 12-ounce (355-ml) bottle of tonic water may pack 124 calories and 32 grams of added sugar, though the exact numbers may differ by brand (4).

On the other hand, diet versions of tonic water are calorie-free.

Fruit-infused or fruit-flavored waters

Fruit-infused or fruit-flavored waters contain herbs and sliced fruits that have been infusing the water for several hours.

Common combinations include:

• blueberry and mango
• cucumber and orange
• grapefruit and rosemary
• raspberry and lime
• strawberry, lemon, and basil
• watermelon and mint

Even if you eat the fruit after drinking the water, you’ll only ingest minimal calories from drinking these waters, as fruits are naturally low in calories.

What’s more, water-soluble vitamins, such as vitamin C, may leech from the fruits into the water, providing additional nutrients.

Lemon water is another popular beverage that’s made from water mixed with fresh lemon juice for flavor. The juice from an entire lemon provides just 11 calories (5).

On the other hand, fruit-flavored water sold in stores may be sweetened with sugar or fruit concentrates and contain more calories. Therefore, it’s important to check the nutrition label.

Protein waters

Protein water contains whey protein isolate, an ingredient that packs a lot of pure protein.

These drinks have become increasingly popular as people look for convenient ways to increase their protein intake. Mounting evidence suggesting that protein plays an important role in weight management, immune health, and healthy aging (6, 7, 8).

Protein waters are great low-calorie, high-protein alternatives to traditional protein shakes.

Per bottle, protein water products typically offer 70–90 calories and 15–20 grams of protein. They’re usually sweetened with natural flavors or sweeteners like stevia (9, 10).

Summary

Tonic waters contribute calories in the form of sugar, while protein waters contribute calories in the form of protein. Fruit-infused waters have few to no calories, but some sweetened waters may not be calorie-free.

There is no formal recommendation regarding how much water you should drink each day.

Your individual needs depend on where you live, how active you are, what you eat, and your body size and age (11).

Still, the National Academy of Medicine established the following general recommendation for daily water intake (12):

• Women: 91 ounces (2.7 liters) of total water per day
• Men: 125 ounces (3.7 liters) of total water per day

Keep in mind that these recommendations include water from all beverages and foods.

About 80% of people’s total water intake comes from water and other drinks, with the remaining 20% coming from food (12).

Foods high in water include fruits and vegetables like watermelon, citrus fruits, cucumbers, and tomatoes.

Caffeinated drinks like coffee and tea also contribute to fluid intake when consumed in moderation, though they’re thought to be dehydrating due to their caffeine content (13, 14).

Summary

How much water you need per day depends on several factors, including where you live, how active you are, what you eat, as well as your body size and age.

Water is needed for temperature regulation, digestion, joint lubrication, waste removal, and nutrient absorption.

While plain water has no calories, tonic and protein waters contribute some calories to your diet. When in doubt, refer to the nutrition label for calorie information.

Daily water needs vary from person to person but can be met through a variety of foods and beverages.