HEED203 Towson Nutrition and Weight Management Discussion You see an advertisement for a special drink that is supposed to eliminate excess body fat while

HEED203 Towson Nutrition and Weight Management Discussion You see an advertisement for a special drink that is supposed to eliminate excess body fat while you sleep. According to the ad, this product helps you lose weight “fast” by increasing your metabolic rate; there is no need to eat less food or exercise more often. Explain why you think this ad is a source of reliable or unreliable health-related information. Chapter 10
Body Weight and
Its Management
Overweight and Obesity
• Conditions characterized by excessive and
unhealthy amounts of body fat
• Result from a complex combination of biological,
psychological, environmental, cultural, and
socioeconomic factors
• Obesity—a chronic metabolic disease that is
extremely difficult to treat
Overweight and Obesity
• The majority of adult Americans have too much
body fat.
• Overweight and obesity are the most common
nutritional disorders in the United States.
• Often result from a combination of poor diet and
lack of physical activity
Overweight and Obesity
• A healthy body is not fat-free.
• Adipose cells store extra energy from food as
triglyceride (fat).
• As more excess energy is consumed, fat cells
continue to store it as fat and increase in size.
• Under certain conditions, more fat cells can
develop.
Defining Overweight and Obese
• Height and weight tables are no longer used to
determine whether a person is overweight or obese.
• The body mass index (BMI) is used to determine if a
person weighs too much.
• BMI is a ratio of height to weight.
– To calculate BMI, multiply weight (lbs) by 705; then
divide the number by height in inches squared.
Body Mass Index
• BMIs less than 18.5 are in the underweight range.
• BMIs between 18.5 and 24.9 are considered healthy.
• BMIs between 25.0 to 29.9 are within the overweight
range.
• BMIs over 30.0 are in the obese range.
• BMIs of 40 or more are referred to as morbid,
extreme, or super obese.
Prevalence of Overweight and Obesity
• In the United States, the prevalence of excess body
fat has reached epidemic proportions.
– In 1980, almost 50% of adults were overweight
or obese.
– By 2012, 2 in 3 adults were too fat and more
than 1 in 3 were obese.
• American children are growing fatter, too.
• The WHO recognizes obesity as a worldwide health
problem (globesity).
Health Risks
• Overweight and obese people have higher than
average risks of:
– Osteoarthritis
– Sleep apnea
– Gallbladder disease
– Carpal tunnel syndrome
– Gout
– Hypertension
– Diabetes
– Metabolic syndrome
– Heart disease
Health Risks
• Certain cancers:
– Colon
– Breast (menopausal women)
– Uterus
– Kidney
– Esophagus
• Surgery is riskier
• Breathing problems
Health Risks
• Fertility problems
• Gestational diabetes, hypertension during
pregnancy, and giving birth to babies with birth
defects
• Interference with daily activities like walking,
carrying, kneeling, and stooping
• Psychological depression, particularly among
obese women
The Caloric Cost of Living
• The body expends 50% to 70% of calories to fuel
vital metabolic activities, including:
– Building and repairing tissues
– Breathing
– Circulating and filtering blood
– Producing and transporting substances
– Maintaining body temperature
The Caloric Cost of Living
• Factors that influence metabolic rate include:
– Genetics
– Hormones
• Thyroid hormone
– Proportion of muscle to fat
– Gender
– Age
– Exercise
The Caloric Cost of Living
• Physical activity
– Calories are needed to move skeletal muscles.
• Number of calories used is influenced by:
– Type of activity
– Duration
– Intensity
– Size of person
Energy for Physical Activities
• The amount of energy needed for physical activity
depends on the activity, its duration, and intensity.
• Physical activities include:
– Sport types of exercise
– Movement for daily living
– Spontaneous muscular movement
Energy for Physical Activities
• Health experts recommend that adults perform at least
30 minutes of moderate-intensity physical activity
daily.
• Each day, the typical American expends more energy
for physical activities associated with daily living than
for sport types of activities.
Caloric Cost of Living: TEF
• Energy expended for physical activity and vital
energy needs require about 90% of body’s energy
use.
• After eating a meal, the body needs a small amount
of energy to digest, absorb, and process nutrients
from food.
• Thermic effect of food (TEF) accounts for less than
10% of total energy needs.
Energy Balance
• When:
– Caloric intake equals caloric output, weight is
maintained.
– Caloric intake is more than caloric output,
weight gain occurs.
– Caloric intake is less than caloric output, weight
loss occurs.
• One pound of fat represents about 3,500 calories.
Body Composition
• Healthy adults consist of:
– About 60% water
– 6% to 22% protein
– 3% minerals
– Remaining weight is mostly fat
• Body fat for healthy adults
– About one-half of an average person’s fat is
subcutaneous.
– “Cellulite” does not exist; it is the same as other
fat.
Estimating Body Fat
• Hydrostatic weighing (underwater)
– Very reliable but not practical or convenient
• Bioelectrical impedance
– Uses electrical currents to estimate percentage of
fat
– Small device needed but can provide accurate
estimate
• Air-displacement plethysmography
– Uses a special chamber (BOD POD) to measure a
person’s body volume
Estimating Body Fat
• Near-infrared interactance (“infrared”)
– Infrared light is used to estimate percentage of fat
(through biceps muscle of upper arm)
– Often underestimates
• Dual-energy X-ray absorptiometry (DEXA)
– Measures fat and bone density
– Accurate, but expensive
– Requires X-ray technician to perform
measurement
Estimating Body Fat
• Skinfold thicknesses
– “Pinch an inch” method
– Practical and less costly than above methods
– Reliability of measurements can be questionable
• Waist circumference
– Determines distribution of fat in abdominal area
– Need flexible measuring tape
Estimating Body Fat
• Distribution of fat is a more important risk factor than
percentage of fat.
– “Apple-shapes”
• More fat in the central part of body than below
waist
• Greater risk of serious health problems
– “Pear-shapes”
• Have excess body fat below waist
• Lower risk of serious health problems than
when fat is centrally located
Causes of Obesity:
Biological Influences
• Genetics
– Genes code for:
• Body frame
• Fat distribution
• Hormones that regulate appetite and
metabolism
– Some people have “thrifty metabolisms” that
tend to conserve energy as fat.
Causes of Obesity:
Biological Influences
• According to the set point theory, the level of
body fat is genetically preset.
• Hunger is the physiological drive to seek and eat
food.
• Appetite is the psychological desire to eat specific
foods.
• Satiety is the feeling that enough food has been
eaten to relieve hunger and turn off appetite.
Causes of Obesity:
Biological Influences
• The digestive system, brain, and fat cells play
important roles in controlling hunger and satiety.
• The composition of the diet can affect body
weight.
– Excess calories from carbohydrate, protein, fat,
and alcohol can result in weight gain.
• A high-fat diet is associated with overeating
and gaining body fat.
Causes of Obesity: Other Influences
• A variety of environmental, social, and
psychological factors promote overeating.
– Portion sizes have increased.
– Certain types of restaurants encourage
overeating.
• Fast food and family-style restaurants often
promote “super-sized” portions as bargains.
– Advertising makes food look more appealing.
Causes of Obesity: Other Influences
– Food availability and convenience, e.g., pizza
delivery 24 hours a day
– Tendency to overeat during holidays and family
gatherings
– Sedentary lifestyles
– Moods
Weight Management
• Balance food intake with energy expenditure.
• Avoid fad diets.
– Usually result in temporary weight loss
– Promote gimmicks
– Often are nutritionally inadequate
– Fasting may be dangerous
• Increase physical activity.
• Change eating and physical activity habits for life.
Role of Physical Activity
• Daily exercise helps people lose or maintain weight.
• Exercise for at least 30 minutes per day.
• Physical activities such as walking, jogging, biking,
swimming are recommended; choose enjoyable
ones.
• People over age 40 should obtain approval of
personal physician before beginning a vigorous
exercise program.
Other Methods of Weight Control
• Surgical methods
– Gastric bypass
– Liposuction
• Medications
– Appetite suppressants
– Fat absorption reduction (small intestine)
Successful Weight Loss Strategies
• Sensible and safe weight loss plans
– Medically and nutritionally sound
– Include practical ways to engage in physical
activity
– Adaptable to psychological and social needs
– Can be followed for a lifetime
Successful Weight Loss Strategies
• Set realistic weight loss goals.
• Emphasize behavior modification.
– Eat nutritiously as well as develop physical
activity habits.
• Follow the MyPlate guidelines.
• Engage in at least 30 minutes of physical activity
daily.
• Seek family or other forms of social support.
• Include long-term plan for maintaining new weight.
Weight Gain
• To gain weight by increasing lean tissue
– Need at least 700–1,000 additional calories per
day
– Eat three meals per day plus snacks.
– No more than 30% calories from fat
• Perform muscle-building exercise.
• Maintain effort over long term.
Across the Life Span
• Average weight gain during pregnancy is 25 to 35
pounds.
– Underweight women can gain more weight;
overweight women can gain a few pounds less
than average, but they should gain at least 20
pounds.
• Food restriction and weight loss may be hazardous
to developing fetus.
• Lose weight before or after pregnancy.
Across the Life Span
• Low-calorie or fat-restricted diets are not
recommended for children under 2 years of age.
• Overweight children need more physical activity.
– Limit time spent engaging in sedentary activities.
• Contrary to conventional wisdom, elderly persons may
enjoy good health and live longer by being overweight
and even obese.
– Serve as energy source
– Can protect from serious internal injuries in the
event of a fall

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