Chapter 10 body weight and management
To estimate your BMI,
BMI, multiply your weight in pounds by 705. Then, divide that number by your height in inches squared.
In 2012, the FDA approved a second prescription drug for long-term use,
Belviq.
Muscle cells use more energy than
Fat cells
What do people with low thyroid hormones experience?
Feel cold, have little energy, be constipated, and gain weight easily.
Although it is not related directly to physical activity, person's body size influences the amount of physical effort needed to move
For example, a person who weighs 120 pounds and another who weighs 175 pounds might spend the same amount of time playing a game of tennis. If both of them play tennis with the same intensity, the muscles of the heavier person require more energy to move than those of the lighter person.
What are the consequences of childhood obesity? According to the Centers for Disease Control and Prevention,42 childhood obesity is linked with the following disorders:
High blood pressure and high cholesterol (risk factors for heart disease and stroke) Type 2 diabetes Breathing problems, such as sleep apnea and asthma Joint problems Fatty liver disease, gallstones, and heartburn Psychological problems, such as depression and anxiety Poor self-esteem Social problems, such as stigma and bullying
therefore, people with greater amounts of muscle mass have
Higher metabolic rates than those with more fat tissue.
Nearly everyone knows what it feels like to be hungry.
Hunger is the physiologic drive to seek and eat food.
Did healthy people meet this objective in 2010?
No
Is the human body fat free?
No
the term overweight to refer to
Overfat
As of 2018, three additional long-term weight-loss drugs have been approved by the FDA:
Qsymia, Contrave, and Saxenda.
Obese older adults who have chronic health problems that are associated with excess body fat can follow the same recommendations for losing weight that younger individuals do:
Select nutrient-dense foods, reduce intakes of fatty and sugary foods, and become more physically active.
Individuals who are overweight can lose body fat and maintain their new weight by following sensible and safe weight-loss plans, which have four major characteristics:
They are medically and nutritionally sound. They include practical ways to engage in regular physical activity. They are adaptable to one's psychological and social needs. They can be followed for a lifetime.
Dissatisfaction with body size is common, particularly among
Western cultures and young women.
gout
a condition that affects joints;
Physical activity alone is not as effective as low-calorie diets for treating obesity because most individuals who are overweight cannot perform enough exercise to create a significant deficit of calories. However, this does not mean that they should
abandon physical activity as a means of losing excess body fat.
The Consumer Health feature "Dietary Supplements: Weight-Loss Aids" provides information
about some popular over-the-counter weight-loss products.
This elevation may result from
an increase in the metabolic activity of muscle cells that occurs after physical exertion.
To measure your waistline, place the tape
around your body just below the ribcage and at the top of the hipbone.
Using skinfold thicknesses to
assess body
Many babies who are overweight at their first birthday slim down by the time they enter school. However, rapid weight gain during the first 2 years of life is
associated with increased blood pressure, BMI, and waist circumference in adulthood.
Events that mark important milestones of life usually include
big meals and special foods.
As a result, cases of obesity are more likely to occur in
certain families.
In developed nations, eating disorders such as bulimia nervosa and binge eating affect
considerable numbers of people, especially girls and women.
You do not even have to leave home to buy food; pizza, Chinese, and other food can be
delivered to your front door.
Some people eat long after satisfying their hunger because they are
excited, anxious, or bored.
As a result, some of the fat in foods is not digested and is eliminated in
feces.
What do people with high thyroid hormones experience?
feel warm, be nervous and shaky, have chronic diarrhea, and lose weight despite eating large amounts of food.
To estimate your daily caloric expenditures, you can add the number of calories needed
for basal metabolism, physical activity, and TEF. I'm
Metabolic rates vary;
genetic factors probably play a major role in setting these rates.
Some fad diets, including the Atkins diet, use carbohydrate restriction as a
gimmick.
Obesity increases one's risk of developing gout,
gout,
Most fad diets do not focus on behavior modification. However, even reliable weight-loss programs that promote behavior modification do not offer
guarantees for long-term success.
Advertisers know the value of making foods look appealing. To stimulate sales, for example, fast-food restaurants show
hamburgers topped with crisp lettuce and bacon extending beyond the bun.
Avocados, olives, and nuts are high in unsaturated fat, which is
healthier than saturated fat.
Very-low-calorie diets or fasts trigger energy- conserving mechanisms in the body that are designed to
help people survive starvation.
The specialists ranked each diet on a scale of 1 to 5 on seven measures: short-term weight loss, long-term weight loss, ease of following, nutrition, safety, performance as a diabetes diet, and performance as a heart diet. U.S. News used scores on all seven measures (not all measures were weighed equally) to compute an overall score for each diet and subsequently ranked the diets from
highest (best) to lowest.
WHat happens if a person eats more food energy than is needed?
his or her fat cells continue storing fat and increasing in size.
The digestive system, brain, and fat cells play important roles in controlling
hunger and satiety.
Genes control the development of many physical characteristics,
including height, fat distribution, and body frame size.
Results of studies do not provide consistent evidence that weight cycling is associated with
increased disease or death.
Since the early 1900s, typical portion sizes of many popular foods have
increased.
Skinfold measurements should be taken at three or more select body sites; averaging these measurements accounts for
individual differences in body fat distribution.
Women who smoke cigarettes or gain too much weight during their pregnancies are more likely to have
infants and young children who are overweight and obese.
Orlistat does not suppress appetite but
interferes with fat digestion.
Women are more likely than men to have
irregular connective tissue under their skin.
Testosterone
is a hormone that stimulates muscle mass development.
When caloric intake is very low, the body burns fat as well as
lean tissue for energy.
Women who are underweight when they become pregnant can expect to gain more weight; those who are overweight may gain
less.
Persons who are lean may have
lower set points than persons who are obese.
Modern technology enables
machines, instead of our muscles, to do much of our work.
Regardless of the type of diet they used to lose excess fat, the majority of persons who were formerly overweight find it difficult to
maintain their reduced body weights.
Children and adolescents need adequate amounts of energy for physical development and activity, but they often eat
more calories than recommended by dietitians.
Small amounts of fat are stored in
muscles, which rely on the fat for energy.
Thus, shedding excess fat to achieve a healthy body weight is
not an easy task.
However, high-fat diets are associated with
overeating and gaining body fat.
These conditions often result from a combination of two behavioral risk factors—
poor diet and physical inactivity.
People who have lost weight with the help of "diet drugs" usually regain it when they discontinue using the
products and following the diet and exercise plan.
6-22% of a healthy adult's weight is,
protein
Although such claims are untrue and not based on scientific evidence, they attract people who are seeking
quick and easy ways to lose their excess body fat.
When people are desperate to lose weight, they are more likely to believe advertisement promises for
rapid weight loss without dietary or physical activity changes.
An objective of Healthy People 2010 was to
reduce the prevalence of excess body fat to 40% of the adult American population.
Improving one's appearance and health were among the reasons subjects gave for deciding to
reduce their excess weight.
People who are physically inactive are likely to gain weight unless they
restrict their food intake.
For example, when people who are lean deliberately overeat to gain weight, they usually lose the extra weight after
resuming their normal eating habits.
Leptin and insulin play important roles in regulating eating behavior, but in people who are obese, these hormones
seem to lose their effectiveness.
Excess body fat, particularly obesity, contributes to many
serious and disabling health problems.
Furthermore, the metabolic rate often remains elevated for
several hours after one discontinues vigorous physical activity.
Our early ancestors probably endured long periods of fasting, interrupted by
shorter periods of feasting.
Fat-soluble vitamins are generally found in fats and oils, so a person taking orlistat will not absorb as many of these nutrients from foods and therefore
should take a vitamin supplement.
Excess body weight can .
stress joints, especially weight-bearing joints in the knees and hips, so they wear out sooner.
Some pregnant women restrict their food intake to limit their weight gain because they do not want to
struggle with losing the extra pounds after the baby arrives.
Certain obese abdominal fat cells (visceral fat) may be more likely to release inflammatory compounds into the blood than
subcutaneous fat cells found in the hips and thighs.
Strands of connective tissue hold
subcutaneous fat in place.
While a person is eating, the intestinal tract releases several chemicals
that signal the brain to eat less food.
In addition to the caloric cost of vital metabolic activities,
the body expends energy to contract skeletal muscles.
When caloric intake is less than caloric expenditures,
the body loses weight as cells burn stored fat.
When food was plentiful, our ancestors thrived on
the bounty.
Many people are unaware of, or they underestimate,
the number of calories that are in their snacks and meals.
After information about the air displacement has been obtained,
the person's fat mass can be calculated.
As with all prescription medications, consumers are cautioned to consider
the risks and benefits of taking weight-loss prescription drugs and to seek the counsel of their personal physician.
The amount of energy needed for physical activity depends on
the type of activity, the time spent performing the activity (its duration), and the intensity at which it is performed.
The BOD POD determines
the volume of air that a body displaces while sitting in the device.
Many health experts think underweight individuals should avoid gaining body fat unless
their condition is the result of chronic illness.
To gain lean tissue, persons who are underweight need to consume at least 700 to 1,000 more calories per day than
they usually eat and perform muscle-building exercises.
If people could pinch a fold of abdominal skin that was more than an inch wide, according to the advertisement,
they were too fat.
However, the number and size of fat cells increase dramatically when
this condition occurs during childhood and other periods of rapid growth.
Compared with original bakery bagels, an average bakery bagel now weighs
three times as much and provides three times the amount of energy.
A gimmick is a promotional feature that makes a fad weight-loss diet appear
to be new, unique, and more effective than other diet plans.
Dual-energy X-ray absorptiometry (DEXA or DXA) is often used in clinical studies
to measure body fat as well as bone density, which is useful for diagnosing osteoporosis (Figure 10.6).
Bodies need energy (calories) to
to survive and thrive.
Therefore, any significant weight loss can be attributable
to the calorie-restricted diet and increased physical activity—not the product.
These nutrient-dense, high-fiber foods are quite filling, and dieters may fail to eat enough to meet their
total permissible number of calories.
An ounce of fat supplies more than
twice the number of calories as an ounce of carbohydrate or protein.
Although it may seem that nearly everyone is on a diet to lose weight, some people are
underweight and trying to gain weight.
Being overweight is not necessarily
unhealthy
Fasting accelerates the loss of fat and lean body tissue, creating
unhealthy metabolic by-products.
That weight, however, does not specify how much
water, muscle, or fat is in your body.
Infancy is a period characterized by rapid gains in both
weight and height.
However, biological, environmental, social, and emotional factors contribute to
weight gain by influencing food intake.
An excess of calories from carbohydrate, protein, fat, and alcohol can result in
weight gain.
Initially, people who are obese typically lose substantial amounts of
weight while following a low-calorie diet or fast.
By identifying and modifying behaviors that resulted in weight gain, a person can develop a
weight-loss and maintenance plan that works best for his or her specific needs.
Each year, Americans spend billions of dollars on various
weight-loss products and services.
On average, men have higher metabolic rates than
women.
Every year, Americans spend money on ineffective treatments to eliminate
"cellulite."
As they reach middle age, women often blame
"gravity" or pregnancy for the expanding dimensions of their waists, hips, and thighs.
too much thyroid hormone
(hyperthyroidism)
healthy adult's weight is
3% minerals.
Each pound of body fat represents about
3,500 calories of potential energy;
In a recent survey of American high school students, about
60% of females and 30% of males reported that they were attempting to lose weight at the time of the survey.
Together, metabolic and physical activity energy needs constitute more than
90% of a person's energy expenditure.
In the United States, excess body fat contributes to more than
90,000 cancer deaths each year.
For example, you may be "stuffed" after eating a Thanksgiving dinner, but when you see pumpkin pie topped with whipped cream, you can find
"room" in your stomach for dessert.
Furthermore, when a person who is obese loses weight, he or she is likely to regain some or all of it within a few years. Why? Some scientists think
"slimmed down" fat cells send messages to the brain that are interpreted as hunger.
Many fast-food and family-style restaurants promote their
"super-size" portions as being bargains.
Frustrated dieters often blame themselves for lack of self-control. Episodes of losing and regaining weight are referred to as
"yo-yo dieting" or weight cycling.
Healthy People 2020 includes two objectives related to obesity:
(1) reducing the proportion of adults who are considered obese (2) reducing the proportion of children and adolescents who are obese.
Thus, what appears to be a lack of progress while restricting food intake and exercising may be the result of a healthy increase in muscle mass.
(This is one reason why measuring one's body fat percentage or waist circumference is more insightful than measuring weight alone.)
Pregnant overweight or obese women have greater risks of developing diabetes
(gestational diabetes),
Too little thyroid hormone
(hypothyroidism)
Belviq was approved for use, in conjunction with a reduced-calorie diet and exercise plan, in adults who are obese
(i.e., have a BMI of 30 or greater) or who have a BMI of 27 or greater and have at least one weight-related health condition (e.g., type 2 diabetes, high cholesterol, hypertension).
After 20 years of age, metabolic rates decline about
1-2% each decade.
When the Hershey chocolate bar was introduced in 1906, it weighed a little over half an ounce; today, a regular-sized Hershey bar weighs
1.6 ounces.
A baby who was 7 pounds at birth, for example, should weigh about 14 pounds at 6 months of age and 21 pounds at
12 months of age.
According to the Physical Activity Guidelines for Americans, adults need l
150 minutes of moderate-intensity aerobic activities each week.16 However, approximately 1 in 5 adults report meeting this guideline.
Fast-food hamburgers and standard servings of french fries and soft drinks are often considerably larger than those served when these popular restaurants first opened in the
1950s and 1960s.
the prevalence of obesity and extreme obesity in the United States has increased steadily for both men and women since the
1980s.
2016 prevalence map illustrates that every state had a prevalence of obesity of at least
20%,
An over-the-counter version of orlistat (Alli) became available in
2007.3/5
The best diets for overall weight loss were computed using the short-term weight-loss and long-term weight-loss measures previously identified. The following diets were identified as the best weight-loss diets: Weight Watchers (with an overall weight-loss score of
3.7 out of 5.0), Volumetrics Diet (3.5), Jenny Craig (3.4), Vegan Diet (3.4), The Flexitarian Diet (3.3), DASH Diet (3.2), The Engine 2 Diet (3.2), Ornish Diet (3.2), Raw Food Diet (3.2), and SlimFast Diet (3.2).
Most individuals who are overweight can safely increase their physical activity by walking, bicycling, or swimming for at least
30 minutes, preferably on a daily basis.
25 states having a prevalence of at least
30%.
Reasonable and reliable diet plans recommend ways to increase physical activity such as by adding
30-90 minutes of walking, swimming, or bicycling to one's routine on most days of the week.
Because fatty foods are a source of considerable calories, physically active individuals can eat as much as
35% of their caloric intake from these items.
The majority of people who have lost weight through nonsurgical methods experience relapse, regaining some or all of the weight within
4 years.
In 2018, U.S. News & World Report published new rankings of
40 popular U.S. diets.32
In 2006, 21% of pregnant women gained more than
40 pounds during their pregnancies.
According to the rule of thumb, healthy babies double their birth weight by the time they are
6 months of age and triple their birth weight by their first birthday.
On average, people who have had gastric bypasses can lose about
60% of their presurgery weight, improving their overall health.
The metabolic rate decreases with caloric restriction, especially when individuals consume fewer than
800 calories a day.
sleep apnea, a condition in which one stops breathing periodically while sleeping.
a condition in which one stops breathing periodically while sleeping.
The only equipment you need to determine your waist circumference is
a flexible but nonstretchable tape measure.
(gestational diabetes),
a form of severe hypertension during pregnancy,and giving birth to babies with birth defects and/or babies who do not survive.
An individual who produces too much thyroid hormone has
a higher than normal metabolic rate.
Most reliable weight reduction regimens incorporate both of these features by combining
a low-calorie diet with a plan that increases physical activity.
Thus, preventing childhood obesity has become
a national health priority.
carpal tunnel syndrome, a painful nerve disorder involving the wrist and hand
a painful nerve disorder involving the wrist and hand
Most people who have lost weight regain some or all of it—and often, even more weight—after
a period of caloric restriction.
Because the equipment needed to perform hydrostatic weighing is not widely available, the method is not
a practical or convenient way to determine a person's percentage of body fat.
Air-displacement plethysmography is
a quick and reliable way to measure fat mass and involves no exposure to radiation as DEXA does.
Leptin, a hormone produced by fat cells, and insulin, the pancreatic hormone that lowers blood sugar levels, affect the hypothalamus,
a region of the brain that regulates eating behavior (Figure 10.11).
why is the body not fat free?
a small amount of fat is essential for the normal functioning of all cells. Additionally, the body has specialized cells called adipose cells that store the extra energy from food as triglyceride (fat).
Today, most Americans have access to
a steady supply of tasty, fattening food.
Instead of using fingers to pinch a section of skin and its underlying layer of fat,
a trained person uses special calipers to measure skinfold thickness more precisely (Figure 10.8).
This use of energy, the thermic effect of food (TEF), accounts for
a very small portion, less than 10%, of one's total energy expenditures.
The reliability of using skinfolds to estimate the percentage of body fat depends on the
accuracy of the calipers, the number of skinfolds measured, and the skill of the person performing the measurements.
A reliable plan, for example, helps a person set an
achievable weight-loss goal, recognize faulty eating habits, build self-esteem and body shape satisfaction, and obtain family or group support.
Women who begin pregnancy at a healthy weight should gain about 25-35 pounds during the following 9 months. This weight gain includes not only the fetus's weight but also the weight of the pregnant woman's
additional body fluids, fat stores, and breast and uterine tissues.
No one can predict whether a child who is obese will become an
adult who is obese.
Some people may develop these psychological conditions
after being discriminated against or having humiliating and embarrassing experiences.
Thus, the typical American diet promotes overeating because it provides
an interesting, tasty, and enjoyable variety of fatty, sweet foods.
Before removing the fat, the area is injected with an
anesthetic containing fluid or treated with ultrasound (ultrasound-assisted lipoplasty).
Obesity can begin at
any age.
Surgery is riskier for people who are obese because physicians have more difficulty estimating the amount of anesthesia needed.
because physicians have more difficulty estimating the amount of anesthesia needed.
The average healthy young woman has proportionately more body fat than the average healthy young man
because the fat is needed for hormonal and reproductive purposes.
Unlike persons with healthy weights, individuals who are obese have less than half of their body fat under their skin,
because they store considerable amounts of fat in their abdomens.
but people who are overweight and have too much body fat are at risk of
becoming obese.
However, caloric restriction during pregnancy may be hazardous to the developing fetus. The time to lose weight is
before or after pregnancy, not during this period.
Effective weight-loss plans usually emphasize
behavior modification.
Appetite is the psychological desire to eat specific foods, which is not the same as
being hungry.
As a result of NEAT, people can reduce the risk of gaining body fat by
being restless and busy because they will metabolize far more energy each day than people who spend much of their day engaging in sedentary activities such as lying down or sitting still.
When subjects have normal amounts of body water (i.e., are adequately hydrated), .
bioelectrical impedance provides reliable estimates of their percentage of body fat
However, overweight and obesity result from a complex combination of
biological, psychological, environmental, cultural, and socioeconomic influences.
Additionally, dieters who follow restrictive diet plans for more than a few weeks often become
bored with the regimens and gradually return to their old eating habits.
People who are obese often have
breathing problems because the excess fat interferes with lung expansion when they inhale.
Men who had trim, athletic builds during adolescence often develop
bulging waistlines by the time they are 40 years old.
The majority of the people who wanted to lose weight used
calorie reduction as their primary method.
People who are overweight may turn to alternative therapies to lose weight, especially if they have had no success with conventional medical weight-loss practices that include
calorie restriction and increased physical activity.
Manufacturers of weight-loss products often recommend that dieters also follow a
calorie-reduced diet and an exercise regimen.
When the caloric intake from food equals the number of
calories expended for energy needs, no change in body weight occurs.
therefore, consuming as little as 100 extra calories per day for a year
can result in a 10-pound weight gain.
Excessive amounts of these substances in the blood increase the risk of
cardiovascular disease and type 2 diabetes.
Dietary supplements, such as those containing
chitosan, green tea, chromium picolinate, and hoodia, are promoted for weight loss.
According to most medical experts, obesity is a
chronic metabolic disease that is extremely difficult to treat.
Successful treatment involves teaching children and their parents how to make appropriate dietary modifications, increase physical activity, and resolve
conflicts that may involve eating habits.
Supermarkets often have a deli section that offers
cooked or fried chicken, baked macaroni and cheese, a variety of potato salads, and other ready-to-eat foods.
Liposuction, a surgical procedure that involves vacuuming subcutaneous fat out of the body, is the most common type of
cosmetic surgery in the United States.
A surgeon drastically reduces the capacity of the stomach by
creating a small pouch in the upper part of the stomach for food to enter.
Each day, the typical American expends more energy for physical activities associated with
daily living than for sports types of exercise.
Although the U.S. News diet rankings provide comparison data between the diets, it is important to note that these
data are not from clinical trials.
Many health experts use the percentage of body fat to determine if a person is overfat.
determine if a person is overfat.
Nevertheless, more research is needed to
determine the role of NEAT in weight maintenance.
For decades, medical researchers have been testing various compounds to
determine whether they can help people adhere to their diet plans more easily or lose weight faster.
On the other hand, babies who are breastfed, particularly for the recommended length of time, are less likely to
develop obesity in adulthood.
BMI correlates body weight with the risk of developing
developing chronic health conditions
Thus, dieters must cut their caloric intakes even further to continue losing weight, which often makes adhering to their diets even more difficult.
difficult.
After eating a meal, the body requires a small amount of energy to
digest, absorb, and process the nutrients from food.
Not surprisingly, many people who are overweight or obese are
dissatisfied and preoccupied with their body image.
Many people seek comfort from eating, especially foods that are fatty and sugary, when they are
distressed or depressed.
BMI is calculated by
dividing weight (kilograms) by height (meters squared): kg/m2.
Cellulite fat, however,
does not exist.
Since 1980, obesity rates have
doubled for American adults and nearly tripled among children and adolescents who are 2-19 years of age.
To obtain the extra calories, people who are underweight can eat more than three meals a day and snack on nutrient-dense foods such as
dried fruit, whole wheat muffins, granola bars, yogurt and fruit smoothies, peanut butter, and nuts.
Many fast-food restaurants, convenience stores, and supermarkets are open 24 hours, many with
drive-through or curbside pickup options so you do not have to get out of a car.
After having this procedure, the patient loses weight rapidly because he or she can no longer
eat large portions of food without vomiting or experiencing uncomfortable feelings of fullness.
Psychological state can influence
eating behavior.
Relapses occur when one fails to modify
eating behaviors and physical has unrealistic weight-loss expectations.
An effective program that helps children lose weight should not interfere with their normal physical development and should not encourage the development of
eating disorders.
Because of the association with cardiovascular disease, people trying to gain weight should avoid
eating excessive amounts of saturated fats.
People who are obese often claim that they gain weight by
eating small amounts of food.
Behavior modification involves learning to identify behaviors that contribute to one's inability to lose weight, such as
eating too much fatty food and not engaging in enough physical activity.
You can use the criteria listed in the Managing Your Health tips titled "General Features of Reliable Weight Reduction Plans" to judge the
effectiveness of most weight reduction methods.
Bioelectrical impedance uses
electrical currents to estimate the percentage of body fat.
Besides improving physical appearance, exercise reduces
elevated blood pressures and lipid levels.
As the body adjusts to the reduced caloric intake, it metabolizes less fat and lean tissue for
energy, slowing the rate of weight loss.
Regardless of the activity, it should be
enjoyable and practical to perform on a year-round basis.
The prevalence of obesity has reached
epidemic proportions in the United States.
Hydrostatic weighing (underwater weighing) is one of the most reliable methods to
estimate an individual's percentage of body fat.
A panel of nationally recognized experts in nutrition, obesity, food psychology, diabetes, and heart disease was assembled to
evaluate the selected diets.
The distribution of body fat may be more important than body fat percentage for determining risk factors for the health conditions that are associated with
excess body fat.
Some members of the population may have inherited metabolisms that "burned off" the
excess food energy as body heat.
Obesity is a condition characterized by
excessive and unhealthy amounts of body fat.
The best way to improve the appearance of thighs and buttocks is to
exercise and lose excess weight.
To avoid regaining weight, successful dieters must make lifestyle changes they can follow throughout their lifetimes, such as exercising regularly and controlling caloric intake
exercising regularly and controlling caloric intake
As a result, the person overeats, and his or her fat cells
expand again.
To lose weight, individuals should eat fewer calories than they need or
expend more calories than they eat via physical activity.
Small incremental changes that are implemented gradually are easier to adopt than
extreme exercise regimens and overly restrictive diets.
The number of fat cells, however, can increase when
extreme obesity occurs during the adult years.
Some of the more popular weight loss diets of the last few decades have included a variety of recommendations such as
fasting, counting calories, not counting calories, avoiding certain food combinations, eating plenty of protein and little carbohydrate, or eating only a few foods.
Water and certain mineral elements conduct electrical currents, whereas
fat is a poor conductor of electricity.
Most of the remaining weight is
fat.
Obese men and women are more likely to experience
fertility problems than people whose weights are in the healthy range.
People who are overweight can lose weight while following fad diets because the diet plans that accompany the gimmicks usually provide
fewer calories than the level of energy supplied by typical American diets.
Some of this slowdown occurs because the body expends
fewer calories to maintain the new weight.
Spontaneous muscular movement includes
fidgeting and maintaining balance and body posture.
Therefore, persons who have thrifty metabolisms
find it difficult to control their weight in such environments.
In addition to ranking these diets by best overall scores, six other rankings were derived from the data from
five measures evaluated by the expert panel, including best weight-loss diets.
You can find other nutritious foods that are high in food energy by consulting
food composition tables.
Carbohydrate-rich foods often taste better when they are
fried or when fats such as butter, sour cream, or gravy are added to them.
Imagine a birthday party or wedding celebration that does not include a
frosted layer cake!
Some fasts permit only
fruit juices and nutrient supplements.
However, people who are overweight often lose weight when following a low-fat, high-complex carbohydrate diet because the food plan includes generous servings of
fruits, vegetables, beans, and whole grain cereals.
In some people, the thyroid gland does not
function properly,
Individuals who are morbidly obese generally experience little success following low-calorie diet plans and exercising to lose weight. In such cases, bariatric surgeries, particularly
gastric bypass procedures, may be used.
Fad diets usually have a few common features—
gimmicks and caloric restriction.
A person who is overweight
has more fat, muscle, bone, and/or body water than a person whose weight is classified as normal (e.g., healthy).
Although people tend to gain fat as they age, the increase does not necessarily cause
health problems.
Although more research is needed, obesity appears to pose more
health risks than does weight cycling.
Most health experts use the body mass index (BMI) instead of _______-height/weight tables to determine whether an individual weighs too much.
height/weight tables
Other fad diets use gimmicks such as prescribed food combinations based on your blood type, dietary supplements that "melt fat while you sleep," and "secret" food ingredients that allow you to eat all your favorite foods or retain fat in desirable places (the breasts of women, for example) while shedding it from the
hips, abdomen, and thighs.
Movement for daily living includes various unstructured physical activities such as housework, gardening, walking, and leisure-time physical activities that are not associated with sports, eating, or sleeping.
housework, gardening, walking, leisure-time physical activities that are not associated with sports, eating, or sleeping.
A variety of methods are used to determine one's percentage of body fat, including
hydrostatic weighing, bioelectrical impedance, dual-energy X-ray absorptiometry, air-displacement plethysmography, and skinfold thicknesses.
Keeping a record of everything you eat and drink each day can also be useful for
identifying problem foods and poor eating habits.
As mentioned in the beginning of this chapter, the percentage of school-aged children who are overweight is
increasing in the United States (Figure 10.14).
People can increase the amount of energy expended during physical activity by
increasing its duration or intensity.
Men and women who have large body fat deposits centrally located deep within their abdomens tend to have higher blood cholesterol levels and a greater risk of developing diabetes, hypertension, and heart disease than
individuals with the same amount of fat located below the waist.
The low-carbohydrate "Atkins diet," for example, gained many followers when it was first introduced in 1973, but dieters soon lost
interest in its restrictive food choices.
Underreporting caloric intake, however,
is common, especially by persons who are obese.
Although the declining metabolic rate is a contributing factor, many health experts think physical inactivity
is more responsible for "middle-age spread" than overeating is..
The metabolic rate
is the amount of energy required to fuel cellular activities within a specified time.
Although the Dexa technique is very accurate for measuring body composition, the equipment
is very expensive and requires trained X-ray technicians to use it.
Furthermore, individuals who exercise for at least 250 minutes per week may be more likely to maintain their weight loss than those who are
less active.
Belviq activates the serotonin 2C receptor in the brain, which may help one successfully eat
less and feel full after consuming smaller food portions.
Liposuction can be hazardous; infections, blood clots, disfigurement, and even death can result. For most individuals who are overweight,
liposuction is not a suitable weight loss method.
For people trying to gain weight, the effort must be maintained over the long term, just as it is for people trying to
lose weight.
By 65 years of age, most people have experienced a decline in their lean mass and an increase in their fat mass. This change occurs to a lesser extent in individuals who
maintain a high degree of physical activity as they age.
Healthy individuals should not fast for more than a day without
medical supervision.
Age also influences the metabolic rate.
metabolic rate.
The proportion of muscle and fat tissue also influences the
metabolic rate.
Those with obesity are also more likely to suffer from
metabolic syndrome, gallbladder disease, hypertension, diabetes, and heart disease.
Hormones, especially thyroid hormone produced in the thyroid gland, regulate
metabolism
The amount of energy needed depends on various factors, such as
metabolism rates and physical activity levels.
When food was scarce, individuals with thrifty metabolisms were more likely to survive than those with
metabolisms that did not store as much excess energy as fat.
Many years ago, advertisements for a breakfast cereal asked people to "pinch an inch" as a
method of determining their amount of body fat.
30 Even though they may have gained the weight gradually, individuals who are overweight or obese who want to lose weight often seek
methods that promise quick and dramatic results.
It is true that a person gains body fat by eating
more food energy (calories) than needed.
composition is not as accurate as the underwater weighing and bioelectrical impedance techniques, but it is
more practical and less costly.
Even modest increases in physical activity, such as walking, swimming, or light exercise, can benefit
most elderly people.
that losing the excess weight involves a considerable amount of
motivation and commitment.
Others had "thrifty" metabolisms that enabled them to store
much of the excess energy as body fat.
. Some individuals are underweight and want to increase their
muscle mass;
Rather than endure periodic fad dieting, people who have excess body fat should consider other, more successful methods of losing weight—
namely, changing eating and exercise patterns for life.
. Nevertheless, cells release much of the calories from food as heat, which is
necessary for maintaining one's body temperature.
Movements for daily living and spontaneous muscular movements are sometimes referred to as
nonexercise activity thermogenesis (NEAT).
People who become overweight in adulthood usually have
normal numbers of fat cells, but their fat cells are larger than normal.
The vast majority of people who have excess body fat, however, have
normal thyroid hormone levels and normal metabolic rates.
Overweight and obesity are the most common
nutritional disorders in the United States.
Although recent years have seen childhood overweight percentages level off,
obesity is still on the rise among American children and adolescents.
Because families share environments as well as genes, and both the environment and genes affect
obesity, obesity is classified as a genomic disease.
For example, some cultures view excess body fat favorably, as a sign of financial security, and may not perceive being overweight as a health risk. Such a perspective could contribute to the incidence of
obesity.
In most cases, there is no single cause for
obesity.
Many American adults are less active physically than when they were younger, partly because they have
occupations that require little physical effort.
People who are obese, particularly women who seek weight-loss treatment,
often suffer from depression and low self-esteem.
Genes may also code for weight gain by determining the production of hormones that regulate
one's metabolic rate and interest in eating tasty foods.
This crude technique of measuring skinfold thicknesses relied on the principle that
one-half of a person's fat is located beneath the skin, if the person has a healthy BMI.
Orlistat (Xenical), approved in 1999, was the
only prescription drug for weight loss approved by the Food and Drug Administration (FDA) for more than a decade.
Foods that are rich sources of simple carbohydrates (sugars) contribute to
overconsumption of calories.
People who are trying to follow low-calorie diets often lose control over their appetites and—as a result—
overeat.
Such food production practices encourage
overeating and excess caloric intake.
Environmental, Social, and Psychological Influences A variety of environmental, social, and psychological factors promote
overeating in the United States.
Many people respond to certain social situations by
overeating.
Many physical health problems result from being
overweight or obese
In 2016, about 65% of American adults were
overweight or obese.
More American infants and preschool children are also
overweight than in the past.
Nevertheless, individuals who are thin are often just as dissatisfied with their body sizes as those who are
overweight.
Children who are obese may develop eating disorders and low self-esteem when
parents, other adults, or peers treat them negatively.
. As a result of this gradual slowdown,
people need less energy as they age.
Human cells use energy (calories) from food to perform vital activities such as
perform vital activities such as building and repairing tissues, circulating and filtering blood, and producing and transporting substances.
Sports types of exercise are
physical activities that are planned and carried out for the purpose of improving health and well-being.
Work and home environments often do not provide opportunities for Americans to be
physically active.
Some people perceive individuals who are obese as
physically unattractive, lacking willpower, and/or lazy.
As such, they should be interpreted as subjective—if expert—opinions and not as objective fact. Persons wishing to lose weight should always consult with their
physician before embarking on a new eating plan to ensure it meets their personal nutritional needs.
When you step on a scale, you can determine your body weight as a number of
pounds or kilograms.
Additionally, weight-loss plans should meet the
psychological and social needs of those attempting weight loss.
These conditions are associated with serious
psychological disturbances.
Such diets are often referred to as fad diets because they remain popular for a period of time and then
quickly lose their widespread appeal.
Therefore, individuals who engage in regular vigorous activity may be able to
raise their resting metabolic rates.
Waist circumference measurements determine the distribution
rather than percentage of body fat.
Metabolism
refers to all chemical changes that take place in cells.
Most desserts and snack foods contain
refined carbohydrates and fat; mixtures of sugar and fat are almost irresistible.
Under these conditions, most fat cells shrink as they
release stored fat to meet the energy needs of other tissues.
However, children and adolescents who are obese are more likely to
remain obese into adulthood.
As a result, the person's fat cells may
resist efforts to lose storage fat.
Presently, there is no
safe or effective treatment that "cures" being overweight.
Acupressure, a therapy that is based on ancient Chinese medicine, is a popular alternative therapy for weight, but there is a lack of
scientific evidence to support its long-term effectiveness.
Despite their efforts, most individuals experience a decline in their rate of weight loss after
several weeks of following a calorie-reduced diet.
Not only do families share common eating and exercise practices, but they also often adopt
similar perspectives regarding body weight and health.
As a result, we tend to spend more time
sitting than walking around during the day.
Therefore, one should strive to prevent excessive weight gain by making permanent lifestyle changes that include appropriately reducing the
size of food portions, especially fatty foods, and increasing physical activity.
There is no difference between the fat cells in
so-called cellulite and those in subcutaneous fat.
The air-displacement plethysmography technique uses a
special chamber (BOD POD) to measure a person's body volume.
These efforts include joining weight-loss programs or spas and buying
special foods, book.s, pills, and gadgets
Some health experts classify physical activities as
sports types of exercise, movement for daily living, or spontaneous muscular movements.
Swimming, brisk walking, and lifting weights are
sports types of exercises.
Exercise retains lean tissue and builds muscle mass, which may
stabilize or even increase one's body weight.
Diets that provide 400 or fewer calories daily are often called fasts. Fasts are essentially
starvation regimens.
Besides subcutaneous and muscle fat, regions of the abdomen, thighs, hips, and buttocks l
store considerable amounts of fat.
As mentioned earlier, the body loses when its caloric intake is less than its energy needs. In this situation, the body relies primarily on
stored fat for energy.
This technique has cosmetic value when used to remove small areas of fat that create unsightly bulges,
such as "saddlebag thighs" or double chins (Figure 10.13).
Furthermore, the body stores more fat when the excess of calories is supplied by dietary fat rather than carbohydrate or protein.
supplied by dietary fat rather than carbohydrate or protein.
Because fat and lean tissue store water, using these tissues for energy creates a
surplus of water in the body.
Some of these diets can be classified as fad diets; others are roadmaps of healthy nutritional plans that could be
sustained over a lifetime.
The process of changing behaviors
takes education, practice, time, and perseverance.
What is the treatment for having high thyroid hormones?
taking medication or have surgery to reduce the amount of hormone produced by the organ.
People suffering from underactive thyroid glands can increase their metabolic rates by
taking thyroid hormone pills.
The sensation of stomach fullness results in
termination of eating.
Although having a high set point may result in an unhealthy percentage of body fat,
that amount of fat may be normal for that person.
Under certain conditions, additional fat cells can develop, further enlarging the fat mass, and this person soon notices
that his belts are too small or her slacks are too tight as a result.
This observation led some medical experts to propose
that the level of body fat is genetically preset.
People who become more physically active while dieting often report
that their clothing fits better, or they can wear smaller sizes even though they have not lost much weight.
Before beginning a vigorous physical activity program, inactive people over 40 years of age should obtain
the approval of their personal physicians.
Nutritionally sound weight reduction diets emphasize nutrient-dense foods, and they are nutritionally well balanced and adequate. Without being overly restrictive, such diets supply fewer calories than one needs. No special foods are necessary; the recommendations of the U.S. Dietary Guidelines and MyPlate (www.choosemyplate.gov) form
the basis of nutritious calorie-reduced daily menus.
If caloric intake is more than caloric expenditures,
the body conserves much of the excess calories as fat, and weight gain occurs.
According to the principles of energy balance, the body gains fat when it has an excess of food energy;
the body loses weight when energy intake does not meet its needs.
The kidneys eliminate the excess water, causing a dramatic loss of weight that often encourages dieters during the early phase of their weight reduction efforts. Within a few weeks, however,
the body regains its normal water balance, and the rate of weight loss slows.
Many people think cellulite is an abnormal type of fat that appears as lumpy, dimpled skin on
the buttocks and thighs.
Once the level of body fat reaches this set point, the metabolic rate and other internal mechanisms maintain
the degree of fatness, like a thermostat can be set to maintain the temperature of a room.
This student has discovered that exercising to lose body fat often does not produce
the desired change in body weight.
Childhood and adolescent obesity often becomes a problem that affects
the entire family.
If these strands hold the fat in an irregular pattern,
the fat tissue can extend into layers of skin, giving the skin a lumpy appearance.
The Diversity in Health essay "The Plight of the Pima" discusses
the harmful effects that genetic and environmental factors have had on the Pima Indian population of southern Arizona.
The amount of weight a woman gains during pregnancy affects
the health of her baby.
Besides dietary factors, preoccupation with sedentary activities such as playing computer games and watching television contributes to
the increase of childhood obesity.
Obesity significantly increases the risk of cancers of
the large intestine (colon), breast (postmenopausal women), uterus, kidney, and esophagus.
More research is needed, however, to determine
the link between abdominal fat and these chronic diseases.
When the Atkins diet was reintroduced about 25 years later, its renewed popularity resulted in
the marketing of a wide array of "low-carb" foods.
hy person's body fat is located in a layer under
the skin (subcutaneous fat).
Although body weight usually fluctuates slightly from day to day, most people report that
their weight remains fairly stable for months, even years.
Body fat is less dense than lean tissues or water;
therefore, extra fat makes the body more buoyant.
Infants and children have higher metabolic rates than adults because
they are growing rapidly.
Once fat cells form, there is little evidence that
they can disappear with short-term weight reduction efforts.
if people continue to eat the same amount of food as their age increases,
they gain weight (assuming consistent activity levels).
Very-low-calorie diets may provide fewer than 800 calories per day and be nutritionally inadequate because
they limit food choices.
When fat cells become too large, they lose their ability to.
they lose their ability to respond to the hormone insulin, which leads to the development of diabetes.
Every day, the body expends the largest portion of calories (50-70%) to carry out these vital activities.
to carry out these vital activities.
Although measuring skinfolds is a popular technique, some health experts challenge the value of skinfold thicknesses
to determine the degree of body fat in individuals who are overweight or obese.
No specific calorie-restricted diet enhances long-term weight loss and maintenance. However, people who are overweight often lose weight when following a low-fat, high-complex carbohydrate diet because the food plan includes generous servings of fruits, vegetables, beans, and whole grain cereals. These nutrient-dense, high-fiber foods are quite filling, and dieters may fail
to eat enough to meet their total permissible number of calories.
After shrinking, fat cells may send chemical signals to the nervous system that stimulate the
urge to eat, making it difficult for people to maintain their reduced body weights.
Sugar-sweetened soft drinks ("liquid candy") are convenient to purchase from
vending machines and convenience stores.
Thousands of years ago, "fat" genes
vital to human survival.
As both men and women grow older, they usually add body fat in their abdominal regions, which often increases their
waist circumference to unhealthy levels.
At home, many people spend their leisure time engaged in sedentary activities such as
watching television or using a computer or hand-held device.
About 60% of a healthy adult's weight is ,
water
Fat-free body weight consists of
water, proteins, and minerals found in the bones, muscles, and organs (lean tissues).
In addition to tracking weekly changes in body weight, physically active people who are overweight can keep
weekly records of waist circumferences.
The person learns to modify inappropriate behaviors so that
weight loss and its maintenance are possible.
Medical experts, however, do not recommend these products because reports of their safety and effectiveness are not based on \
well-designed clinical studies.
According to a recent survey, the majority of American adults who were overweight or obese
were trying to lose weight.
Individuals who lose weight while following fad diets are prone to relapse
when they return to their usual food habits.
Actors in food ads appear to be happy and satisfied with their food choices. Today, it is easier to obtain meals and snacks
when you are not at home than in the past.
As one grows older, exercising regularly can help retain muscle,
which slows the metabolic rate decline.
When one or both parents are obese, they are more likely to have offspring
who gain excessive amounts of body fat than are two parents of normal weights.
Nevertheless, within 2 years of giving birth, many women remain several pounds heavier than those
who have not been pregnant.
There is a widespread misperception that persons who are overweight or obese lack the
willpower to control their eating and weight.
Because men normally produce more testosterone than women, men usually have more muscle and less fat than
women
Calorie and fat-counting guides are helpful if
you are trying to control your weight.
By eating more fruits and vegetables and fewer sugary and fatty foods, you can control your caloric intake.
your caloric intake.
