British tap water is mostly free of the bugs that cause gastric infections and waterborne diseases
　　Can water make you fat? It sounds absurd, the kind of suggestion peddled by some New Age psycho-babble diet.
　　After all, can there be anything in our diet that equals the critically important role played by water in maintaining our health?
　　Water is the foundation of life, the major content of most organisms, the primary component of our cells and is responsible for aiding thousands of chemical processes in the body.
　　What is more, there is surely nothing more refreshing than a long, cool, sparklingly clear glass of water poured straight from the tap?
　　As a doctor of more than 20 years' standing, the answer has to be a resounding no.
　　Yet when we do drink it, how many of us get the healthy water we deserve?
　　Thanks to the possible pollutants that are so difficult to remove from our water supply, it has been linked to a number of health complaints - and yes, it may even trigger weight gain.
　　Even calorie-free water can affect our body fat levels if chemicals that disturb hormonal activity leach into our supply and drive up our chances of putting on weight.
　　Celebrities trying to keep trim and maintain a youthful look drink up to 3 litres of water a day.
　　WATER WITH EXTRAS
　　Our tap water is, by and large, safe and mostly free of the bugs that cause the gastric infections and waterborne diseases in other parts of the world.
　　The main purification processes are good at freeing our supply of these potentially harmful microorganisms --although a recent report found that 40 per cent of water in London still has a lead content that is higher than European regulations. (Lead in water has been linked to abnormal brain development in unborn babies.)
　　Indeed, though I live in beautiful rural Yorkshire, where you'd think the water would come sparkling out of the tap, it is a fairly unappetising colour thanks to the old (though not lead) pipes that serve my home.
　　Problems such as this arise because filtration does not always sift out up to 60,000 dissolvable chemicals that can get into our water supply.
　　Among these are the so-called gender-bending chemicals such as Bisphenol A (BPA) - used in the manufacture of plastics such as babies' bottles - which various studies have linked to reproductive difficulties, as well as cardiovascular disease and diabetes.
　　A recent study by Harvard School of Public Health found that those who drank from bottles made with BPA showed a two-thirds increase of the chemical in their urine
　　WHY WOMEN ARE TO BLAME
　　Other chemical derivatives to get into our water include oestrogen compounds.
　　These can come from pesticides and herbicides that wash off from soil into our rivers.
　　Oestrogen is the hormone that stimulates female characteristics in women at puberty.
　　Synthetically it is used in the oestrogenbased oral contraceptive pill. Again this is excreted in urine and gets into our water supply.
　　An excessive amount of oestrogen in the body not only drives certain cancers such as specific types of breast cancer, but also affects the way we accumulate fat.
　　So the more we are exposed to oestrogen, or chemicals that act like it, the harder it is to lose body fat. And an increase in body fat has been linked to many illnesses including heart disease and cancer.
　　Meanwhile, we have to consider the population-wide drop in sperm concentration which has plummeted, according to the British Fertility Society, by about 30 per cent, as well as the fact that Britain seems to be gripped by a fertility crisis.
　　One in six couples have difficulty conceiving and nearly 37,000 people a year are having IVF. Chemicals in our water could be driving this reproductive calamity.
　　FILTER OUT THE ENEMY
　　Buying a water filter may help remove heavy metals from our water supply, but filters may not catch all dissolvable chemicals and micro-organisms.
　　I believe the best way to serve ourselves the cleanest water possible is to use a reverse osmosis purification kit.
　　This is attached to your pipes and works by filtering water through a semi-permeable membrane that stops most contaminants passing through.
　　It can be expensive - from £125 to £3,000 - but is a small price to pay for healthy water.
　　Of course, it would make more sense for our suppliers to introduce this method at source, but the processes required to remove chemicals and pharmaceuticals at this level are not financially viable for the water authorities at present.
　　IS BOTTLE BEST?
　　Some would argue that it is simply better to drink bottled water. But aside from the plasticising chemicals-that are used in some bottles, there is a potential health issue.
　　When you open bottled water, it is no longer sterile and so sits like a stagnant pond attracting bacteria.
　　If you want to bottle your tap water once you have filtered it, an alternative is to buy an eco product such as the Bottle for Life, a BPA-free stainless steel bottle that you can fill up and keep in the fridge.
　　Remember that water is only as good as the route of its delivery. There's no point in any of us trying to eat healthily and exercise if we don't do something about our water. It's something we should all drink to.