We've all heard it's important to drink plenty of fluids, especially in the summer when we sweat more. But not all fluids are created equal, especially if you're watching your waistline. Our nutrition expert Leslie Beck tells us what to drink and what to avoid.
Q: First, how much water should we be drinking each day?
According to the Institute of Medicine of the National Academy of Sciences adult males need to drink 13 cups (3 litres) of water each day and women need 9 cups (2.2 litres). Kids' needs vary with age: 4 to 8 year-olds require 5 cups (1.2 litres), 9 to 13 year olds need 8 cups (1.8 litres), teenaged girls should drink 8 cups (1.8 litres), while older boys need 11 cups (2.6 litres)of water per day.
Daily Water Requirements
Kids, 1-3 years 4 cups (1 litres)
Kids, 4-8 years 5 cups (1.2 litres)
Kids, 9-13 years 8 cups (2 litres)
Teens, 14-18 years 8-11 cups (2 to 2.7 litres)
Women, 19+ years 9 cups (2.2 litres)
Men, 19+ years 13 cups (3 litres)
These guidelines don't take into account factors that drive up your daily water requirements. Hot and humid weather cause your body to sweat more and increase your fluid needs. And there's also the exercise factor. Physical activity generates heat in your muscles which your body releases through your skin as sweat. If you don't drink enough before, during, and after exercise your body can't properly release this heat. As a result your heart beats harder, your body temperature rises, and ultimately your performance suffers.
Q: What happens if you don't drink enough water? What are the signs of dehydration?
If you don't consume enough fluid to replace losses you'll start to feel dizzy, lightheaded, fatigued and may get a headache and develop muscle cramps. Other signs of mild to moderate dehydration include thirst, decreased urine output, flushed skin, dry mouth and eyes, nausea and loss of appetite.
If dehydration progresses, extreme thirst, lack of sweating, low blood pressure, rapid heartbeat, muscle spasms and heat injury can occur. Heat injury results from drinking too little fluid combined with heavy exercise and sweating. Symptoms can range from mild heat cramps to potentially life threatening heat stroke (when the body's sweating mechanism shuts down and the body is depleted of fluids).
Some people are at greater risk from suffering the effects of dehydration and need to pay close attention to their water intake. Young children, older adults, people working outdoors in hot weather, and people with poorly controlled diabetes and other chronic illnesses are more susceptible to becoming dehydrated.
Q: What beverages count towards your daily water intake?
Well here's the good news: all beverages, with the exception of alcoholic beverages, count towards your daily water requirements. Even tea and coffee count towards your daily fluid intake. Although caffeine - found in coffee, tea, chocolate, colas and some medications - causes the kidneys to excrete water, there's no evidence that habitual intakes cause a deficit of body water over the course of a day.
Q: So which beverages are better than others?
There are definitely better fluid choices, particularly if you're counting calories. Research suggests that we don't register the calories we drink as well as the calories we eat. Liquid calories add on to, rather than displace, food calories thereby increasing our total daily calorie intake. The fact that liquid calories can easily lead to weight gain prompted a U.S. research panel to publish a "Beverage Guidance System" that ranks beverages based on their calorie and nutrient content.
Plain water outranked all over beverages because it has no calories, no sugar, no sodium and may provide some calcium, magnesium and fluoride. Water was followed by, in order, unsweetened coffee and tea, low fat milk and soy beverages, diet drinks, calorie beverages with some nutrients (e.g. fruit juice, sports drinks), and lastly sugary beverages (soft drinks, fruit drinks). To prevent getting too many calories from fluids, here is the panel's recommendation:
#1 Water 0 calories 4 to 6 servings per day
#2 Unsweetened tea and coffee 0-3 calories 0 to 5 servings per day
#3 Low fat milk 100-150 calories 0 to 2 servings per day
#4 Diet drinks 0 calories 0 to 4 servings per day
#5 Caloric drinks w/ nutrients 75-250 calories 0 to 1 serving per day
#6 Sugary drinks w/o nutrient 100 -175 calories 0 to 1 serving per day
One serving = eight ounces (250 ml)
To prevent consuming too many calories from beverages, the panel recommends limiting drinks to at most 10 percent of daily calories. In other words, you shouldn't sip more than 200 calories, if you follow a 2000 calorie diet.
