Updated 05 October 2015

Water, diet and nutrition

Water maintains and regulates the body's systems, including the gastrointestinal tract, and it acts as a preventative measure against common diseases and disorders.


Water maintains and regulates the body's systems, including the gastrointestinal tract, and it acts as a preventative measure against common diseases and disorders.

Water is one of the body's main foods

Although it has no calories, we need water more than we need any other nutrient. Our bodies use water along with food as fuel to keep them in a good condition.

Water transports trace elements, nutrients and hormones into the cells and intercellular spaces. Water tones up the muscles, keeps the skin supple, regulates the body's temperature, lubricates the joints and keeps the mind alert.

The body has a reserve of nutrients, but it has no reserve of water. The body cannot rehydrate itself and thirst appears as a general warning of dehydration.


Water is the medium which permits the body's various chemical and enzymatic reactions: it carries nutrients, hormones, antibodies and oxygen by means of the blood flow and the lymphatic system.

Digestive system

In order to be useful to the body, most foods and nutrients have to be broken down into simpler substances. This is called digestion.

Solid foods cannot be digested without water. The gastric juices, such as the enzymes in the stomach, transform the food into a homogenous substance, which can then pass into the intestine. Constipation is often a sign of dehydration.

Water also helps the body to eliminate toxins and waste.


The kidneys remove waste, urea and lactic acid from the body. All these substances have to be dissolved in water. When a person is dehydrated, these substances cannot be removed from the kidneys, and this could damage them.

You and thirst

When you feel thirsty, your body is giving the signal that it is feeling dehydrated. We would only be able to survive for a few days without water. It is not necessary to wait until you feel thirsty before you drink water. When you feel thirsty, your body is already dehydrated to a degree.

Getting into a habit of regularly drinking water at certain times of the day will keep you adequately hydrated. It is a good idea to get into the habit of taking bottles of water with you to the gym and to the office – wherever you may need it.

You should drink at least 1.5 litres of water a day, depending on your body weight, the outdoor temperature and your activity levels.

What about drinking at mealtimes?

Contrary to popular belief, drinking at meal times aids our digestive process. Our bodies use water for digestion, absorbtion of nutrients, and for excreting waste. Drinking water at mealtimes is a good way of recouping water losses incurred during the day.


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