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Weight Management
Achieving and Maintaining a Healthful Body
Weight
5/9/07
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
What is a Healthful Body Weight?
A healthful weight
• Is appropriate for your age
• Is maintained without constant dieting
• Is acceptable to you
• Is based on family history of body shape and
•
weight
Promotes good eating habits and allows for
regular physical activity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
What is a Healthful Body Weight?
Underweight: having too little body fat to
maintain health.
Overweight: having a moderate amount of excess
body fat.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
What is a Healthful Body Weight?
Obese: having an excess of body fat that
adversely affects health.
Morbid obesity: body weight exceeding 100% of
normal, creating a very high risk for serious
health complications.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
A person’s actual weight is not the only factor to
consider.
Determining if a person’s body weight is
healthful should include:
• Determining the Body Mass Index (BMI)
• Measuring body composition
• Assessing the pattern of fat distribution
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Body Mass Index
• Expresses the ratio of a person’s weight to the
•
•
square of their height
BMI = weight (kg) / height (m)2
BMI values below 18.5 or above 30 have
increased risks of health problems
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Mortality risk vs. BMI
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Body Composition
• Measurement of body fat and lean muscle mass
• Can be measured by
• Underwater weighing
• Skinfold measurements
• Bioelectric impedance analysis
• Near infrared reactance
• Bod Pod™
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Fat Distribution Pattern
• Measured by waist-to-hip ratio and waist
•
circumference
Apple-shaped fat patterning - upper body
• Increased risk for chronic diseases
• Pear-shaped fat patterning – lower body
• No significant increased risk for chronic diseases
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Evaluating Body Weight
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Gaining or Losing Weight
Whether a person gains or loses weight depends
on
• Energy intake vs. energy expenditure
• Genetic factors
• Childhood weight
• Behavioral factors
• Social factors
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Balance
Energy balance
• Occurs when energy intake = energy
•
•
expenditure
Energy intake = kcal from food
Energy expenditure = energy expended at rest
and during physical activity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Balance
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Balance
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Balance
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Intake
Calculating the energy that is in a particular food
• Carbohydrate is 4 kcal/g
• Protein is 4 kcal/g
• Fat is 9 kcal/g
• Alcohol is 7 kcal/g
1 cup of quick oatmeal has 142 kcal
• 6 grams protein x 4 kcal/gram = 24 kcal
• 25 grams carbohydrate x 4 kcal/gm = 100 kcal
• 2 grams fat x 9 kcal/gram = 18 kcal
• Total kcal = 24 kcal + 100 kcal + 18 kcal = 142 kcal
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Total Energy Expenditure
Total energy expenditure =
basal metabolic rate (BMR)
+
thermic effect of food (TEF)
+
energy expended in physical activity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Balance
Basal Metabolic Rate (BMR)
• Energy expended to maintain basal, or resting,
•
•
•
functions of the body
Basal metabolism is the highest proportion of
total energy expenditure
More lean tissue increases your BMR
BMR decreases with age
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Energy Balance
Thermic Effect of Food (TEF)
• Energy expended to process food
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Physical activity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Genetic Factors
Genetic factors account for about 25% of a
person’s body fat.
Different ideas have been suggested to explain
the impact of genetics on body fat.
• Thrifty Gene Theory
• Set-point Theory
• Leptin Theory
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Genetic Factors
Thrifty Gene Theory
• Proposes that a gene (or genes) causes people to
•
•
be energetically thrifty
Proposes that people with this gene expend less
energy than other people and therefore gain
weight
A “thrifty gene” has not been identified
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Genetic Factors
Set-Point Theory
• Proposes that each person’s weight stays within
•
a small range (set point)
The body compensates for changes in energy
balance and keeps a person’s weight at their set
point
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Physiologic factors
•Hunger
•Proteins released by body (hormones, peptides)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Physiologic Factors
Leptin
• Leptin is a hormone produced by fat cells that
•
•
causes reduced food intake, reduced weight,
decreased body fat
Leptin is controlled by the ob gene
Mutation of the ob gene causes reduced levels
of leptin leading to increased food intake and
reduced energy output
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Physiologic Factors
Ghrelin
• Ghrelin is synthesized in stomach, functions as
•
•
a hormone
Role in appetite regulation through its actions
on the hypothalamus
Stimulates appetite, increases amount of food
one eats
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Physiologic factors
Peptide YY (PYY)
• PYY is produced in the gastrointestinal tract
• Released after meal in proportional amounts to
•
•
the energy content of the meal.
Functions to decrease appetite, decrease food
intake
May play important role in obesity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Childhood Factors
Environmental factors in childhood can influence
• Food choices
• Activity levels
• Later adult behaviors
Childhood overweight increases the risk of heart
disease and premature death as an adult.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Behavioral Factors
Food Choices
The composition of a person’s diet should
remain balanced.
Hunger vs. Appetite
Appetite, a psychological desire to eat, can
cause people to overeat.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Social Factors
Social factors influencing our diet include:
• Family or cultural traditions
• Holidays and celebrations
• Easy access to high-fat foods
• Less physically active lifestyles
• Societal expectations of the “perfect” body
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Determining Kilocalorie Needs
The most accurate way to determine your energy
needs:
• Calculate your BMR
• BMR = weight (kg) x 1.0 (for men)
• BMR = weight (kg) x 0.9 (for women)
• Add the energy required to maintain your
activity level to your BMR
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Achieve & Maintain Healthful Weight
Healthful weight change requires
• Gradual change in energy intake
• Regular and appropriate physical exercise
• Application of behavior modification
techniques
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Achieve & Maintain Healthful Weight
Effective weight loss should include
• Following recommended serving sizes
• Reduced intake of high-fat and high-energy
•
foods
Regular physical exercise
• To increase energy expenditure
• To increase BMR
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Achieve & Maintain Healthful Weight
Weight loss medications and herbal supplements:
• May have dangerous side effects
• Many have been removed from market
• Should only be used if a person has
• A BMI of 30 kg / m2
• A BMI of 27 kg / m2 and other health risk factors
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Achieve & Maintain Healthful Weight
Effective weight gain should include
• Eating 500 to 1,000 extra kcal/day
• Eating frequently throughout the day
• Maintaining a balanced diet, limiting fat intake
•
•
to 15-30% of total energy intake
Avoiding tobacco products which depress
appetite and increase BMR
Regular exercise with resistance training
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Protein supplements
•Do not increase muscle growth or strength
•Claim to be anabolic (increase muscle mass)
• Protein supplements
• Androstenedione (affects HDL and LDL
negatively)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Anabolic steroids
•Cause major health problems, including:
• Unhealthy changes in blood cholesterol
• Mood disturbances
• Testicular shrinkage in men
• Breast enlargment in men
• Irreversible clitoral enlargement in women
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Underweight
• BMI below 18.5 kg / m2
• Increases the risk of infections and illness and
•
can even be fatal
Can be just as unhealthy as overweight
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Overweight
• BMI between 25 and 29.9 kg / m2
• Increases the risks of high blood pressure, heart
•
disease, type 2 diabetes sleep disorders,
osteoarthritis, gallstones
Can lead to obesity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Obesity and Morbid Obesity
• Obesity: BMI from 30 to 39.9 kg / m2
• Morbid obesity: weight that exceeds 100% of
•
•
normal
5 of the 9 leading causes of death in the US are
associated with obesity
A multifactorial disease – many things cause
obesity
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Treatments for obesity may include
• Low-calorie diet and regular exercise
• Prescription medications
• Surgery
• Gastroplasty
• Gastric bypass
• Gastric banding
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders Related to Energy Intake
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Great websites for BMI calculation
National Heart, Lung, and Blood Institute: BMI
Calculator
http://www.nhlbisupport.com/bmi/bmicalc.htm
Centers for Disease Control: BMI Calculator and
Factors that Affect BMI
http://www.cdc.gov/nccdphp/dnpa/bmi/bmi-forage.htm
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings