chapter 7 Flashcards
BMI
- weight/height
- worst method to assess body weight
obesity trends in canada
- increasing over the years
- higher in older people
- higher in us than canada
chances of being obese lower with
- more fruits and veg
- more physical activity
limits of BMI
- doesnt represent body composition
- inaccurate for those: with lots or little muscle mass, pregnant, under 18 or over 65
body composition
- can measure % body fat
- men and women differ on what % is excessive
- increased risk of health problems
skin folds
- 2 compartmental
- not accurate for obese
- not accurate for seniors
- requires skill and training
underwater weighing
- can be accurate
- fat less dense than lean tissue
- uses equations
air displacement plethsymography
- bod pod
- similar to underwater
- uses air instead of water
- accurate
bioelectrical impedence
- low energy current to body measures resistance to electrical flow
- fat resistant to flow
- varies by hydration
waist to hip
- greater disease risk with an apple shapped body, excess fat around abdomen than pear shape
waist circumference
- just as good as waist to hip
- better than just bmi
- men +102 cm = health risk
- women +88cm = health risk
thigh circumference
- small (<60cm) assocaited with increased risk of cardiovascular and coronary heart diseases
DXA
- dual energy x ray absorptiometry
- most accurate
hyperplasia
- increase in total number of cells
hypertrophy
increase in cell size
weight loss
- number of adipocytes stays the same
- body wants to refill fat cells so must excersie lots post weight loss
obesithy environmental factors
- socioeconomic status
- social factors
- urbaniation - vehicle use
- mechanization
metabolic syndrom
- large waist
- high triglyceride levles
- reduced hdl levels
- increased bc
- elevating fasting blood glucose
obesity lifestyle factors
- lack of physical activity
- psychological factors encouraging overeating
- smoking
obesity biological factors
- genetics
- sex and age
- race and ethnicity
health risks of obesity
- hypertension
- heart disease
- diabetes
- cancer
- joint diseases
- gout
- gallbladder disease
- sleep apnea
weight loss surgury risks
- increased infections
- blood clots
- adverse reactions
- staples may loosen
components of energy expenditure
- physical activity
- thermic effect of food (easy to digest and absorb)
- resting energy expenditure
resting energy expenditure (REE)
- energy for body functions
- affected by body size, composition, age, M/F
thermic effect of food
- energy used to digest, absorb, metabolize food
- higher for CHO and protien than fat
estimated energy requirement (EER)
- to figure out how many k cals someone needs
- takes into account age, weight, gneder, height, ohysia activity
- overestimates seniors and underestimates kids
- predicts total energy expenditure
estimating energy expenditure method 1
resting energy expenditure: - men = weight x 1 x 2, women = weight x .9 x 24
- physical acitivty: add a % of REE
- TEF: 5-10% of ree and physical activity
estimating energy expenditure method 2 haris benedict
- estimates resting energy needs (REE)
- considers height, weight age and gender
- men: 66.5 + (13.8) x weight) + (5 x height) - (6.8 x (age in y)
- women 66.1 + (9.6) x weight) + (1.5 x height) - (4.7 x (age in y)
thrifty gene theory
- genes cause people to be energetically thrifty
- gain weight m ore easily
- no gene has been identified
set point theory
- each persons weight predetermined to stay within a range
- body compensates for changes in energy balance and keeps weight at set point
- explains why dieting doesnt work
leptin theory
- hormone produced by fat cells
- causes reduced food intake, reduced weight, decreased body fat
- if mutation in ob levels (gene that controls leptin), reduced levels lead to increased food intake and reduced energy outptu
regulation of intake
- hungre
- satiation - signal to stop eating
- satiety - lack of hunger
- appetitte
macronutrient best for satiety
- protein then fat
environmental factros
- hypothalamis reglates temp
- cold eat more than when hot
- increases metabolic rate
- eat more = insulation
neurological and hormonal factors
- neuropeptide Y stimulates apetite