How much water should we actually drink every day?

It is common knowledge that drinking as much as two liters or 8 cups of water per day (sometimes called “8 x 8” for short) is healthy. It supposedly contributes to weight loss and healthy skin, and even fights cancer and kidney stones. It is also advised that such a water amount should be consumed in addition to our normal food and liquid intake, as some (such as caffeinated drinks) are considered diuretic (any substance that promotes the production of urine). But is it really true? Is there any scientific evidence to support such advice? According to Heinz Valtin and his study published in the American Journal of Physiological—Regulatory, Integrative and Comparative Physiology, there is no scientific proof to support the “8 x 8” recommendation. What’s more, caffeinated drinks such as coffee, tea, and soda, as well as mild alcoholic beverages like beer, may be counted toward the daily total water intake. However, such a conclusion is limited to healthy adults who live a sedentary life in a moderate climate. The “8 x 8” recommendation is still valid for the treatment or prevention of some diseases, or for vigorous work and exercise in hot climates.

The above study supports the approach “drink to thirst.” In fact, drinking too much could have fatal consequences, causing (among other things) hyponatremia or water intoxication, which happens when we drink a lot and additionally lose sodium during sport activities.

So, what should we drink?

The choice of soft drinks nowadays is enormous. Brands are competing to get new clients and trying to increase their share in the market by releasing new tastes, colors, and names. The sizes of containers seem to be increasing too.

Since its invention in the 1970s, high-fructose corn syrup has become the best friend of the soda industry. First of all, it is cheap, as corn cropping was subsidized by the federal price support. Secondly, high-fructose corn syrup is liquid and can be directly added to any drinks.

In 2011, Americans drank 32 gallons (121 liters) of soda per year per person and 14 gallons (53 liters) of other sweetened drinks (teas, sports ades, vitamin waters, energy drinks).

A single 12-oz (355 ml) can of Coca Cola contains 39 grams of sugar, which is far above the daily sugar limit. Unfortunately, the human body has difficulty identifying the calories in sweet liquids as well as it can do in solid foods. In other words, the body cannot protect itself against uncontrolled intake of calories from drinks, resulting in excessive weight gain.

The sole conclusion is that sweetened drinks contribute to weight gain, while the increase in sugar intake may lead us straight to diabetes.

What choices do we have apart from soda?

Natural fruit juice (fresh-squeezed, not from concentrate—pure with nothing added except possibly citric acid as a conservative). Juice with fruit pulp is better than filtered juice, as it is a rich source of fiber. You may try to dilute your juice with water just to save some calories for stronger cravings. If you dilute it with sparkling water and add some lemon, the cocktail can be quite a treat, but remember that the amount of sugar in fruit juice is as high as in most sodas.

12 oz can (approx.. 370g) Coca cola Orange juice Apple juice Grape juice Grapefruit juice
Energy (kcal) 331.6 328 328 320 333.7
Carbohydrates (g) 39.2 38.7 42.0 56 34.1
Fiber (g) 0 0.7 0.7 0.8 0.4
Sugars (g) 39.8 31.3 35.8 53.9 33.7



Tea and coffee, as mentioned above, are diuretics, but are not as dangerous for body hydration level as we used to think. There are many types of coffee and tea, and many have benefits. We will write more about them soon.

Water with lemon has almost no sugar and an almost certainly beneficial influence on the body. It hydrates you, flushes out toxins, and rejuvenates the skin. Lemon water is alkaline, so it balances the pH into more alkaline, which is healthier.

Apart from this, lemon water:

  • is a great source of vitamin C, which boosts the immune system.
  • balances the pH level of the body.
  • flushes out toxins.
  • helps digestion
  • helps the production of bile
  • is a source of citric acid, polyphenol, and ascorbic acid.
  • is a source of copper (which facilitates iron uptake), calcium (which builds strong bones and enables cell transport), and potassium (which regulates blood pressure and helps muscles work).
  • is antibacterial.

Mineral water (still and sparkling) rich in basic elements such as sodium, calcium, and potassium is great for the acid-alkaline balance of our body. You can also add mint leaves, strawberries, or slice of orange, all of which will certainly add great flavor.

Distilled water is produced by distillation, deionization, or reverse osmosis. Basically, those processes remove impurities from water and water’s minerals. It is fantastic for steam irons but not for us—humans or animals. Drinking distilled water, especially while fasting, contributes to a loss of electrolytes such as sodium, potassium, and chloride, and may cause problems with heartbeat and blood pressure. As distilled water is mineral-free, it tends to absorb minerals from whatever it comes into contact with; our body will lose minerals if we drink it. Distilled water will also absorb carbon dioxide from the air and become more acidic. More alarmingly, distilled water is popularly used in the production of soft drinks. Drinking soda, therefore, instead of mineral water will never hydrate the body, but it will definitely remove huge amounts of minerals from the body.

Stick to mineral water as often as possible.


Source: Valtin, H., 2002. “Drink at least eight glasses of water a day.” Really? Is there scientific evidence for “8 x 8”? American journal of physiology. Regulatory, integrative and comparative physiology, 283(5), pp.R993–R1004.