9
Chapter Features
Chapter 13 Healthy Weight Management
315
Losing Excess
Body Fat
People who are overweight due to
excess body fat would improve their
health by reducing their fat stores.
Creating an energy imbalance is
required for weight loss. Numerous
strategies for accomplishing this goal
are promoted in books and magazines.
Some of these strategies are safe
and effective, others are dangerous.
Knowing some basic information can
help overweight people make sound
weight-management decisions.
People should consider several
factors when thinking about beginning
a weight-loss program. One factor is
health status. Women should not try to
lose weight during pregnancy. Nutri-
tious foods and a minimum weight
gain are required to ensure the health
of a developing fetus. People who are ill
avoid restricting calories to lose
weight. The body needs an adequate
of nutrients to restore health.
Meeting these nutrient needs
when calories are severely
restricted.cultdiffiis
Age is another issue to keep in
mind when considering a plan to
reduce body fat. Weight loss is not
recommended for children and teens
who are still growing. Losing weight
could permanently stunt their growth.
The recommendation for children and
teens is to hold weight steady and grow
into it. If a child is extremely obese,
then health care supervision is needed.
People need to evaluate their
motivation and body structure when
considering weight loss. The main goal
of weight management is good health.
People who try extreme weight-loss
methods to achieve an unrealistically
slim appearance may put their health
at risk. Remember, weight above a
standard range is a health risk only if it
is due to excess body fat. Weight due to
muscle mass is not a cause for concern
and does not indicate a need for weight
loss.
13-5
Students need to balance time
spent in sedentary study with time spent in
physical activity.
Sports Nutrition Consultant
Sports nutrition consultants work under contract
with healthcare facilities or in their own private
practice. They perform nutrition screenings for their
clients and offer advice on diet-related concerns
related to sports nutrition. Some work for wellness
programs, sports teams, and coaches.
Education:
Sports nutrition consultants need at
least a bachelor’s degree. Licensure, certification, or
registration requirements vary by state.
Job Outlook:
Applicants with specialized training,
an advanced degree, or certifications beyond the
particular state’s minimum requirement should enjoy
the best job opportunities. Employment is expected to
increase.
Career boxes
explore the
education requirements
and job outlook for various
careers in the nutrition and
wellness industries
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Chapter 10 Water: The Forgotten Nutrient
245
Fluid Imbalance
The thirst mechanism is not always
a reliable indicator of fl
uid needs.
During hot weather or heavy exercise,
the body may lose a fair amount of
fl
uid before signaling thirst. When the
body either loses or takes in too much
water, fl
uid imbalances result.
Effects of Water Loss
Because fl
uids make up a high
percentage of your body weight, when you
lose water, you also lose weight. Someone
who wants to drop a few pounds may
think this is good news. However, the
weight you want to lose is fat, not water.
Water weight is quickly regained when
body fl
uids are replenished.
Even a small percentage weight
drop due to water loss will make you
feel uncomfortable. When you lose two
percent of body weight in fl
uids, you
will become aware of the sensation of
thirst. Both the brain and the stomach
play a role in making you aware there
is a water imbalance. If you do not
replace water losses, you may become
dehydrated.
Dehydration
is a state in
which the body contains a lower-than-
normal amount of body fl uids.
When dehydration occurs, the
body takes steps to help conserve
water. Hormones signal the kidneys to
decrease urine output. Sweat produc-
tion also declines. As the volume of
fl
uid in the bloodstream drops, the
concentration of sodium in the blood
increases. The kidneys respond to
the higher blood sodium level by
retaining more water. These water-
conserving efforts cannot prevent all
fl
uid losses from the body. If fl
uids are
not replaced, the damaging effects of
dehydration will begin to take their toll.
Some older adults do not always recog-
nize the thirst sensation. In cases such as
these, it is important not to wait for the thirst
signal to begin consuming liquids. Older
adults may need to make a point of drinking
even when they do not feel thirsty.
Replacing lost water is important
for peak athletic performance. Athletic
performance levels decline after a
3 percent loss in water weight. When
water is lost from working muscles,
blood volume decreases. The heart
must pump harder to supply the same
amount of energy. Mental concentration
is affected as fl
uid losses increase. Some
clear signs of dehydration are fatigue
and lack of energy. Other symptoms
may include dizziness, headache,
Taryn is a 15-year-old girl who lives in Denver,
Colorado—also known as the “Mile High City.” Taryn
loves to spend many hours playing basketball outside
in the summer months. It is hot, sunny, and dry in the
summer. There is a water fountain in a building near
the basketball court, but she does not bother to take
the time to drink. Her friends tell her to bring a water
bottle with her. She usually forgets the water and
thinks it is not that important anyway. Sometimes she
remembers on her way to the game and buys a can
of soda from a vending machine.
Taryn is often disappointed with her game. She
finds that she runs out of energy by mid-game and
often gets a headache. She wants to improve so that
she can make the high school team next year.
Case Review
1. What do you think is contributing to Taryn’s
disappointing performance on the basketball court?
2. Why do you think Taryn believes that water is not
important?
Case Studies
illustrate
chapter concepts with
real-life scenarios and
follow-up questions
242
Part Three The Work of Noncaloric Nutrients
an increased volume of body fl uids
to support their developing babies.
Lactating women need fl
uids to
produce breast milk. People on high-
protein diets require extra water to
rid their bodies of the waste products
of protein metabolism. A buildup of
these waste products can cause kidney
damage.
Older adults have the same need
for fl
uids as young adults. The thirst
mechanism of older adults can change
and fl
uid intake can be affected. Some
older adults choose to limit water
intake if they have urinary inconti-
nence problems. This requires medical
treatment to avoid dehydration.
Adequate fl
uid intake is necessary for
continued good health through the
aging years.
Supplying the Body’s Water
Needs
Drinking liquids generally supplies
the greatest amount of fl
uids. Of course,
plain water is a pure source of this vital
nutrient. However, milk, soft drinks,
juices, broth, tea, and other liquids also
have high water content.
You may be surprised to learn
foods supply almost as much of your
daily water needs as liquids. Most foods
contain some water. Some foods are
higher in water content than beverages.
As an example, summer squash is 96
percent water, whereas orange juice
is only 87 percent water. Even foods
that look solid are a source of water.
For instance, bread is 36 percent water.
Butter and margarine contain water, but
cooking oils and meat fats do not,
10-5.
Roughly 12 percent of your water
needs are met through metabolism.
When carbohydrates, fats, and proteins
are broken down in the body, some
water is released. Your body can
then use this water in other chemical
reactions.
Making Conversions
According to the Dietary Reference Intakes for
water, the AI for 14- to 18-year-old males is 3.3 liters
per day and 2.3 liters per day for females in this
age range. Liters (L) and milliliters (mL) are metric
system units used to measure volume. The following
are common U.S. and metric system conversions:
1 L = 1000 mL
30 mL = 1 fl. oz.
8 fl. oz. = 1 cup
4 cups = 1 quart
1. Convert the AIs for 14- to 18-year-old males
and females from liters to fluid ounces.
(round up to one decimal)
2. Convert the fluid ounces to cups for both
groups.
10-4
Infants need more water per unit of
body weight than children and adults.
Chapter
Fluid Imbalance
The thirst mechanism is not always
a reliable indicator of fl
uid needs.
During hot weather or heavy ext ercis e,
the body may lose a fair amoun
of
fluid
before signaling thirst. When the
these, it is
impo
signal to begin
adults may nee
even when
the
Repla cin
for p
eak athl
performance
3 cent los
Math Links
provide
opportunities to develop
related math skills