Energy Balance and Weight Management Chapter 7. Overweight and Obesity Major health problem in the...
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Transcript of Energy Balance and Weight Management Chapter 7. Overweight and Obesity Major health problem in the...
Energy Balance and Energy Balance and Weight ManagementWeight Management
Chapter 7
Overweight and ObesityOverweight and Obesity
Major health problem in the U.S. Growing concern worldwide
Prevalence increasing among all socioeconomic groups 2/3 of adults Children: 1/3, ages 2-19
Overweight: BMI of 25-29 Obese: BMI of 30 or greater Epidemic is worldwide
Not merely among industrialized countries
This Took 20 Years!This Took 20 Years!
What’s Going On? Increased Intake
– Portion Distortion– Appetite versus
Hunger Decreased Energy
Expenditure– Changes in
recreational activities– Modern technology
Weight Management Terms Energy balance occurs when energy consumed
equals energy expenditure. Energy is measured in kilocalories (kcal, kcalories)
or kilojoules (kjoules, kJ). A kcalorie is a measure of the amount of energy
that is supplied to or expended by the body. Body Mass Index (BMI) is a mathematical
comparison of weight to height Overweight is being too heavy for one’s height or
having a BMI of 25–29. Obesity is characterized by excess body fat or a
BMI over 30.
Energy In: Food Energy In: Food CompositionComposition
Direct measure of food’s energy value Bomb calorimeter
kCalorie calculations Not an exact
science when it comes to how food behaves the body!
Energy BalanceEnergy Balance
Excess energy is stored as fat Fat is used for energy between meals
Energy balance: energy in = energy out A shift in balance causes weight changes
Not simply fat changes When weight loss occurs, body energy stores
are used When weight gain occurs, body energy stores
are built
Energy Balance: Ins vs. Outs
Using Nutrients for Energy (ATP)
Storing Energy in Adipose Tissue
Fat Cell Development Energy in exceeds energy out
Stored in fat cells of adipose tissue Body fat
Number and size of fat cells Periods in life when fat cell numbers increase:
puberty and excess intake Cell proliferation
Energy out exceeds energy in Fat cell size decreases; no change in number
During growth, fat cells increase in number.
When energy intake exceeds expenditure, fat cells increase in size.
When fat cells have enlarged and energy intake continues to exceed energy expenditure, fat cells increase in number again.
With fat loss, the size of the fat cells shrinks but not the number.
Estimating Energy Estimating Energy RequirementsRequirements
Gender BMR
Growth Groups with
adjusted energy requirements Infants, children,
adolescents, pregnant and lactating women
Age Tends to decrease with
time Physical activity
Kcal burned in moment vs. afterburn
Body composition & body size Height Weight
Estimated Energy Requirement
Physical Activity Factor (PA)
Estimating PA Intensity
Calculating Body Mass Calculating Body Mass IndexIndex
Body mass index (BMI) Relative weight for height
BMI = weight (kg)
height (m)2
Health-related classifications Underweight: <18.5 Healthy weight: 18.5 to 24.9 Overweight: 25-29.9 Obese: 30 or above
Not a measure of body composition!
Assessing Body Composition
Bioelectric impedance analysis Skinfold thickness Underwater weighing Dilution methods Radiologic methods
Measurement of Body Composition
Excess Body Fat and Disease Risk
Body Fat and Its Body Fat and Its DistributionDistribution
Important information for disease risk How much of weight is fat? Where is fat located?
Ideal amount of body fat depends on individual
Healthy ranges Men: 13-21% Women: 23-31%
Obese individuals: up to 70% body fat
Body Fat and Its Body Fat and Its DistributionDistribution
Weight alone doesn’t tell the whole story! Waist circumference
Indicator of fat distribution & central obesityWomen: risk at greater than 35 inchesMen: risk at greater than 40 inches
Waist-to-hip ratio: Women: risk at greater than 0.8 Men: risk at greater than 0.9
Fat Distribution: Visceral Fat Distribution: Visceral FatFat
Apple- vs. Pear-Shaped Apple- vs. Pear-Shaped BodiesBodies
Health Risks Associated Health Risks Associated with Body Weight & Body with Body Weight & Body FatFat
Risks associated with being overweight Obesity is a designated disease
Health risks Heart disease, hypertension, diabetes, sleep apnea,
osteoarthritis, some cancers, gallbladder disease, kidney stones, infertility, complications in pregnancy and surgery
More likely to be disabled in later years Costs
Money: health care costs as much or more than that of smoking
Lives: ~300,000/year from related diseases
Estimating Disease Risk
Who would benefit from weight loss?
DefininDefining g Healthy Healthy Body Body WeightWeight What is ideal?
Not appearance-based Perceived body image and actual body size
can be quite different Dissonance can lead to damaging behaviors
Subjectivity of ideal body type Shifts from one culture to another, from one
decade to the next Little in common with health
Body Fat and Its Body Fat and Its DistributionDistribution
Health Risks Associated Health Risks Associated with Body Weight & Body with Body Weight & Body FatFat
Body weight and fat distribution correlate with disease risk and life expectancy Correlations are not causes Overweight does not equal unhealthy
Risks associated with being underweight Fighting against wasting diseases Menstrual irregularities and infertility Osteoporosis and bone fractures
Health Risks Associated Health Risks Associated with Body Weight & Body with Body Weight & Body FatFat