Please consult with your Doctor before
starting any diet plan
The
Wonders of Water
How much you really need - and how it can
help you lose weight.
Water is one of the most basic elements of life but figuring out how
much we ought to drink hasn't always been so simple.
Most of us grew up thinking we needed to drink eight glasses of water
each day, in addition to any other drinks we might choose. But the latest
recommendations say that we no longer need to worry about drinking
specific amounts of water. Instead, we can simply satisfy our thirst with
any beverage.
The New Fluid Guidelines
A 2002 study published in the American Journal of Physiology
questioned the old recommendation of 8 ounces of water, eight times a day.
After a thorough review, researcher Heinz Valtin concluded there was
inadequate evidence that healthy adults -- living in temperate climates
and not engaged in rigorous activities -- need large amounts of water.
For normal, healthy adults, Valtin recommended simply drinking when
thirsty. And he reported that even caffeinated drinks can count toward
satisfying our fluid requirements.
In February 2004, the Institute of Medicine (IOM) issued new
recommendations that agree with Valtin's findings. The new guidelines
remove the eight-glasses-a-day recommendation, and say healthy adults may
use thirst to determine their fluid needs. Exceptions to this rule include
anyone with a medical condition requiring fluid control; athletes; and
people taking part in prolonged physical activities or whose living
conditions are extreme.
How Much Is Enough?
The IOM report did not specify requirements for water but made general
fluid intake recommendations of 91 ounces (that's 11-plus cups a day) for
women and 125 ounces (15-plus cups a day) for men. Remember, these
guidelines are for total fluid intake, including fluid from all food and
beverages.
Approximately 80% of our water intake comes from drinking water and
other beverages, and the other 20% comes from food. Assuming these
percentages are accurate for most of us, the recommended amount of
beverages, including water, would be approximately 9 cups for women and
12.5 cups for men.
While 20% may seem like a lot of fluid to get from food, many common
food items are mostly water. Here are some foods with high water content,
according to the American Dietetic Association:
|
Food
|
Percentage Water
|
|
Lettuce (½ cup)
|
95%
|
|
Watermelon (½ cup)
|
92%
|
|
Broccoli (½ cup)
|
91%
|
|
Grapefruit (½ cup)
|
91%
|
|
Milk (1 cup)
|
89%
|
|
Orange juice (3/4 cup)
|
88%
|
|
Carrot (½ cup)
|
87%
|
|
Yogurt (1 cup)
|
85%
|
|
Apple (one medium)
|
84%
|
Physical activity, heat, and humidity can increase our fluid needs. In
these situations, keep water bottles close at hand and drink frequently to
avoid dehydration. If you're going to be physically active for long
periods, consider sports drinks that hydrate and provide easily usable
sugar and electrolytes.
Illnesses accompanied by increased body temperature, excessive
perspiration, vomiting, frequent urination, or diarrhea can also increase
our fluid needs. Be sure to drink plenty of liquids if you have one of
these conditions, and see a doctor if your fluid losses are excessive or
prolonged.
How Much Is Too Much?
Scientists on the IOM panel did not set an upper limit for water.
"Water intoxication is very rare, although it has been seen in
fraternity pranks. That can be very serious and result in death" says
David Perlow, MD, an Atlanta-based urologist.
One recent study of Boston Marathon runners showed that one in three
marathon runners was drinking too much water during a race -- probably
because they were following recent advice to drink as much as tolerated.
If you follow your thirst, you won't go wrong, Perlow says. He notes
that pre-modern man never ran around sipping on a water bottle. A dry
mouth indicated it was time to run to the stream for a drink.
"Trust your thirst instinct to make sure you get enough fluids
and, of equal importance, void frequently," suggests Perlow.
Perlow says the bladder is like a balloon. When you make infrequent
trips to the bathroom, it can become overstretched -- which can result in
problems with incomplete emptying, he explains.
He recommends 7-12 trips to the toilet daily for most healthy people.
Water and Weight Control
For years, drinking water has been recommended for
weight loss -- despite the fact that it satisfies thirst and not hunger.
Barbara Rolls, PhD, an expert on thirst and satiety, points out that
thirst and hunger are regulated by entirely different mechanisms
A recent study by Rolls and colleagues at Penn State University looked
at whether people who drank water with lunch took in fewer calories than
those who drank other low-calorie beverages. They found that drinking
water had little effect on total calorie consumption at the meal.
"In all of our research, we have never been able to show that
water can cause weight loss," says Rolls. The only way drinking water
can help you lose weight is if you substitute it for higher-calorie
beverages or foods, she explains.
However, eating foods with high water content can help dieters, by
increasing the fullness factor.
"When you add water to a bowl of vegetables as in soup, the soup
has greater satiety than when the vegetables are eaten alone with a glass
of water," explains Rolls, author of The Volumetrics Eating Plan
and The Volumetrics Weight Control Plan. "When water is
incorporated into food or shakes, satiety is increased and subjects
ultimately eat less food."
The weight loss benefits of water stem from several facts:
- Foods that incorporate water
tend to look larger.
- The higher volume of these
foods provides greater oral stimulation.
- Most important, when water is
bound to food, it slows down absorption and lasts longer in the belly.
A soon-to-be-published study by Rolls and colleagues shows that a
high-volume eating plan resulted in more weight loss than a low-fat eating
plan.
If you want to lose weight, Rolls recommends an eating plan that
includes plenty of high-volume foods such as fruits, vegetables,
broth-based soups, and oatmeal, along with adequate fluids to satisfy your
thirst.
Bottom Line
The experts agree: Drinking water -- either sparkling or flat and
perhaps with a twist of citrus -- is a great, noncaloric way to satisfy
your thirst.
But if you struggle with drinking water, you're off the hook as long as
you:
- Enjoy plenty of high-volume
foods, including fruits and vegetables.
- Satisfy your thirst with a
variety of healthy, low-calorie beverages such as 100% fruit juice,
skim or low-fat milk, tea, and, of course, water.
- Pay attention to signs of
dehydration, such as dry mouth and concentrated urine, which indicate
a need for more liquids.
SOURCES: American Journal of Physiology, Aug. 8,
2002
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