Transcript Chapter 10 Lecture Reaching and Maintaining a Healthy Weight © 2015 Pearson Education, Inc.

Chapter 10 Lecture
Reaching and
Maintaining a
Healthy Weight
© 2015 Pearson Education, Inc.
LEARNING OUTCOMES
• Define overweight and obesity, describe the current
epidemic of overweight/obesity in the United States and
globally, and understand risk factors associated with
these weight problems.
• Describe factors that place people at risk for problems
with obesity. Distinguish between factors that can and
cannot be controlled.
• Discuss reliable options for determining percentage of
body fat and a healthy weight for yourself.
• Discuss the roles of exercise, diet, lifestyle modification,
fad diets, and other strategies of weight control, and
which methods are most effective.
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Reaching and Maintaining a Healthy Weight
• The United States is among the fattest nations
on Earth.
• Obesogenic characterizes environments that
promote increased food intake, nonhealthful
food, and physical inactivity.
• Overweight refers to having body weight more
than 10 percent above healthy levels.
• Obesity refers to having body weight more than
20 percent above healthy levels.
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Some of the World's Most and Least
Overweight Countries
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Obesity Trends among U.S. Adults, 1990,
2000, and 2011
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Potential Negative Health Effects of
Overweight and Obesity
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Reaching and Maintaining a Healthy Weight
(cont.)
• Nearly 26 million people have diabetes, which is
associated with being overweight and obese.
Another 79 million have prediabetes.
• Diabetes is among the costliest of diseases, with
estimated costs over $245 billion per year.
• Globally, more than 1 billion adults and 200
million school-aged children are overweight; 475
million adults and 50 million school-aged
children are obese.
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Factors Contributing to Overweight and
Obesity—Genetic and Physiological Factors
• Genes
– The exact role of genes remains in question.
– Obese parents tend to have overweight
children.
– Twins raised separately tend to be the same
weight.
– Thrifty gene theory
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Factors Contributing to Overweight and
Obesity—Genetic and Physiological Factors
• Metabolic The basal metabolic rate (BMR) is the minimum rate at
which the body uses energy when at complete rest.
– Resting metabolic rate (RMR) includes BMR plus additional
energy expended through daily sedentary activities.
– Exercise metabolic rate (EMR) accounts for the remaining
caloric expenditures.
• There are many theories about what might affect metabolic
rates.
– One theory suggests that the hypothalamus that monitors eating
does not work properly in obese people.
– Another suggests that thin people send more effective
messages to the hypothalamus, known as adaptive
thermogenesis.
– Set point theory suggests bodies try to maintain weight within a
narrow range or at a set point.
– Yo-yo diets are cycles in which people diet and regain weight.
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Factors Contributing to Overweight and
Obesity—Genetic and Physiological Factors
• Hormonal Influences: Ghrelin and Leptin
– Less than 2 percent of obese people have a
thyroid problem.
– Ghrelin, the hunger hormone, may play a role
in appetite stimulation.
– Leptin, an appetite regulator produced by fat
cells, increases in the blood as fat tissue
increases. Receptors do not seem to work
well in obese people.
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Factors Contributing to Overweight and
Obesity—Genetic and Physiological Factors
• Fat Cells and Predisposition to Fatness
– Some obese people may have an excessive
number of fat cells.
• A normal weight individual has between 25 and 35
billion.
• A moderately obese individual may have 60–100
billion.
• An extremely obese person may have 200 billion.
– Called hyperplasia, this type of obesity begins
in childhood, perhaps owing to the mother's
dietary habits.
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Factors Contributing to Overweight and
Obesity—Genetic and Physiological Factors
(cont.)
• Critical periods for development of hyperplasia are
the last 2–3 months of fetal development.
– This theory suggests that the number of fat
cells does not increase in adulthood, but the
ability of the cells to swell (hypertrophy) and
shrink does occur.
– Weight gain may be tied to both the number
of fat cells in the body and the capacity of
individual cells to enlarge.
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Factors Contributing to Overweight and
Obesity—Environmental Factors
• Greater Access to High-Calorie Foods
– Advertising promotes eating, emphasizing
good taste over the poor nutritional value of
what is being sold.
– Super-sized portions are the norm.
– Increased reliance on restaurant and
convenience foods.
– Misleading food labels
– Fast-food restaurants, cafes, vending
machines, and quick-stop markets.
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Factors Contributing to Overweight and
Obesity—Environmental Factors (cont.)
• Early Sabotage: A Youthful Start on Obesity
– Over 17 percent of all children and
adolescents are now obese.
– Sedentary activities (social media, video
games, television) have replaced vigorous
physical activity.
– It may be too dangerous for children to walk
to parks and schools.
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Factors Contributing to Overweight and
Obesity—Environmental Factors (cont.)
– Maternal nutrition, obesity, and diabetes
during gestation and lactation may play a role
in predisposing the fetus to becoming
overweight.
– Race and ethnicity interwoven with
environmental factors increase risk for
obesity.
– Obesity stigma is a major threat to overweight
and obese children's self-esteem.
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Factors Contributing to Overweight and
Obesity—Environmental Factors (cont.)
• Psychosocial and Economic Factors
– Eating may soothe fears, sadness, and worry
for some.
– Socioeconomic factors can provide obstacles
or aids to weight control.
• Lack of Physical Activity
– One third of adults never engage in any
exercise, sports, or physical activity.
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Assessing Body Weight and Body
Composition
• Some body fat is essential for health.
– Essential fat is needed for the maintenance of
life and reproductive functions.
– Storage fat, the nonessential fat, makes up
the remainder of the fat reserves.
– Being underweight, or having extremely low
body fat, can cause problems.
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Body Mass Index (BMI)
• A description of body weight relative to height
that is highly correlated with total body fat.
• It is not gender specific and does not measure a
percentage of body fat, but rather provides a
measure of being overweight and obese rather
than just weight alone.
• Calculated by dividing by weight in kilograms by
your height in meters squared.
• Healthy weight is a BMI between 18.5 and 24.9;
25 to 29.9 indicates overweight, and over 30 is
obese. Over 40 is morbidly obese.
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Body Mass Index
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Limitation of BMI
• Water, muscle and bone mass are not included
in BMI calculations.
• BMI levels don't account for the fact that muscle
weighs more than fat, meaning a well-muscled
person could be classified as obese.
• People who are under 5 feet or are older, have
little muscle mass and so BMI levels can be
inaccurate.
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Youth and BMI
• Over 17 percent of youth are obese.
• BMI ranges above normal weight are labeled as
"at risk for overweight" and "overweight" to avoid
the sense of shame that words like "obese" and
"morbidly obese" may cause.
• BMI ranges for children and teens take into
account normal differences between boys and
girls.
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Waist Circumference and Ratio
Measurements
• Where you carry fat may be more important than
how much you carry.
• Abdominal fat is more threatening than fat in
other regions.
• A waistline greater than 40 inches in men and
35 inches in women may be indicative of health
risk.
• A waist-to-hip ratio greater than 1 in men and
greater than 0.8 in women indicates health risk.
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Measures of Body Fat
• Men's bodies should contain between 8 and 20
percent total body fat; men who exceed 22
percent are overweight.
• Men with a body fat measurement between 3 and
7 percent are considered underweight.
• Women should be within the 20 to 30 percent
range; women who exceed 35 percent are
overweight.
• Women with a body fat measurement between 8
and 15 percent are considered underweight.
• Health may be compromised by too little body fat.
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Body Fat Percentage Norms for Men and
Women
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Overview of Various Body Composition
Methods
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Managing Your Weight
• Improve your eating habits
– What causes you to eat? What are your
triggers?
– Seek assistance from professionals or
reputable sources.
• Understand calories and energy balance
– 3,500 extra calories results in an extra 1
pound of storage fat.
• Include exercise
– Increasing BMR, RMR, or EMR will help burn
calories.
– Increasing your muscle-to-fat tissue ratio will
burn more calories.
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Avoid Trigger-Happy Eating
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Analyzing Popular Diet Programs
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Analyzing Popular Diet Programs (cont.)
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ABC News Video: Keeping it Off
Discussion Questions
• Discuss the practical methods used for keeping
weight off.
• Discuss psychological factors or contributors for
the inability to maintain weight loss.
• What tips would you give someone who wanted
to lose weight safely and to maintain weight
loss?
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Energy Expenditure = Energy Intake
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Some Perspective on Weight Control Efforts
Considering Drastic Weight-Loss Measures
• Very-Low-Calorie Diets
•
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Must be medically supervised
Formulas with daily values of 400 to 700 calories
Can cause significant health risks
Ketoacidosis is one potentially dangerous complication
• Drug Treatment
• FDA approval is not required for over-the-counter "diet aids"
or supplements
• Dangerous side effects and potential for abuse
• Surgery
• A last resort and particularly for people who are severely
overweight and have weight-related diseases
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ABC News Video: Best Diet Plan
Apparently Works
Discussion Questions
• Why do you think the Weight Watchers program
has been so successful? What role does social
support play in the program?
• What are some recommendations or strategies
for those who want to lose weight but cannot
afford Weight Watchers?
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Trying to Gain Weight
• Determine why you cannot gain weight; reasons
may be metabolic, hereditary, psychological,
and others.
– Perhaps you are an athlete and burn more
calories than you consume.
– Perhaps you are stressed and skip meals.
– Older adults lose the sense of taste and
smell, making eating less pleasurable.
– Visual and dental problems may make eating
more difficult.
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Tips for Gaining Weight
• Eat more frequently
• Put extra spreads (peanut butter, cream cheese,
or cheese) on your foods.
• Take seconds whenever possible.
• Add high-calorie drinks such as whole milk.
• Eat with people you are comfortable with.
• Exercise can increase appetite; moderate
extreme exercise.
• Avoid diuretics, and relax.
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