Joanna is a registered nutritionist and dietician with a PhD in nutritional science from the University of Sydney. She is the resident nutrition expert for Channel 9’s Today Show, contributor to magazines including Life Etc and Slimming & Health and author of numerous books including Inner Health Outer Beauty, Star Foods and the Low GI Diet.
Drink 8 glasses of water a day. Where did that come from? Despite becoming an accepted dictum, the idea of a set number of glasses of water a day for all of us to consume is nonsensical. How much water you or I need to drink depends on many factors such as:
When you consider how many variables there are, you can see that it is impossible to set one recommendation to cover all our fluid requirements. But there is one sure fire test to see if you are drinking enough — when you go to loo do a colour check. Pale, straw-coloured urine equals good hydration. Conversely the darker it is, the more dehydrated you are.
What is for sure is that many people go through their usual day in a state of mild dehydration. The thing is that our thirst mechanism that drives us to seek out fluid is not all that quick off the mark, nor is it terribly sensitive. By the time we feel thirsty, we are already markedly dehydrated. Being dehydrated by only 1-2% is enough to affect your mental and physical performance. There is little doubt therefore that many of us are almost continually running below par, simply because we are not drinking enough.
Symptoms of being even mildly dehydrated can include fatigue, headaches, trouble concentrating, difficulties in controlling body temperature, dry skin and constipation. The kidneys are also likely to suffer, as they have to deal with a far more concentrated solution and therefore conditions such as kidney stones can result. You may also find yourself more prone to urinary tract infections since less frequent trips to the bathroom allow more time for bacteria to take hold and multiply.
Water is without doubt the best drink for everyday frequent use. It contains no kilojoules, no undesirable additives and does the job of maintaining hydration levels throughout the body. If you also choose to drink Pureau water whenever you can, you are further assured of no chemicals like chlorine, no residual heavy metals like lead, no nasty bacteria or other micro-organisms.
The fact that water is naturally kilojoule free is particularly important. More and more of us battle with our weight each year and drinks can be large part of the problem, even so-called healthy drinks such as fruit juice. The trouble is that liquid kilojoules bypass many of the appetite and satiety systems in place to help our brain control the amount of food that comes in. We need to chew and digest foods for these systems to work properly. Drink too many and your brain continues to instruct you to eat the same volume of food and you wonder why you are slowly gaining weight. Fruit juices, low fat smoothies and other seemingly healthy drinks usually contain just as many kilojoules as soft drinks, sometimes more. Yes they do also provide good nutrients, so needn’t avoid them altogether, but include them as a snack or part of a meal and only once a day.
Tea and coffee does not dehydrate you as commonly thought. Yes caffeine has a mildly diuretic effect, but since you also consume liquid with the drink there is a net gain of fluid. But do try to skip the sugar, the flavoured syrups and full fat milk. All of these add kilojoules few of us need. Learn to enjoy these beverages black or with a little skim milk or dairy alternative.
I’m not going to say too much about soft drinks — you can guess what my views are here! They are loaded with sugar or artificial sweeteners, diet or regular they are acidic and erode your teeth, they almost all contain chemical flavourings, colourings and preservatives, and they encourage a sweet tooth. Enough said.
Water is the fluid of choice to hydrate during most exercise of 90 minutes duration or less. Since most of us exercise at least in part to help us control our level of body fat, the last thing you want to be doing is taking on board kilojoules from sports or other drinks. Stick to water and you will reach your goals more easily.
Sports drinks are however much better at hydrating as they are specifically formulated for fast absorption. The small amounts of glucose and electrolytes are essential during any longer term exercise, or for those who sweat excessively and find it difficult to maintain hydration. In these situations invest in a proper sports drink.
250ml orange juice
1/4 tsp salt
This will make a litre of a hypotonic sports drink — in other words it will be absorbed faster than water and so is best for optimum hydration.
For more prolonged endurance exercise you are best with a drink that provides a compromise between hydration and providing fuel to top up carbohydrate stores. In this case you want an isotonic drink as follows. This will be absorbed as fast as water but with the added benefit of a carb boost:
500ml orange juice
1/4 tsp salt