week 8 - weight + weight management Flashcards
take home messages for weight management + obesity
- obesity reached epidemic amounts
- caused by complex range
of factors that vary across
populations
- caused by complex range
proper weight management involves a healthy relationship w/ food and physical activity - have psychological and environmental control
short term solutions to weight issues are rarely effective in long temr
- FAD diets aren’t usually
sustainable
body composition
Proportion of fat-free mass and body fat in ur body ideal for overall health
Divided into fat-free mass and body fat
- FFM= body’s non-fat tissues: bone, water, mucle, connective tissue
- Fat is in nerves, brain, heart, lungs, liver - main source of stored energy in body -cushions body organs and helps regulate body temp
Whats important for health is proportion of body’s total weight - percent body fat - basically being overfat
Subcutaneous fat
just beneath skin, protective for diseases. The normal physiological buffer for excess energy intake - when storage capacity is exceeded, fats accumulates in other places
visceral fat
embedded in mesentery (tissues that connect intestines to back of abdominal wall) surrounding abdominal organs. Excess linked to CVD and other diseases. 10-20% of total fat in men and 5-8% in W
ectopic fat
located on or within organs, liver, heart, brain. Increases risk for metabolic syndrome, CVD and stroke
obesity
The condition of having an excess of non-essential body fat; having a body mass index of 30kg/m2 or greater.
BMI
A measure of relative body weight that takes height into account and is highly correlated with more direct measures of body fat; calculated by dividing total body weight (in kilograms) by the square of height (in metres).
Based on concept that weight should be proportional to height - frequently used in studies involving health risks associated w/ body weight
Does not distinguish between fat weight and fat-free weight , can be inaccurate for some groups (short ppl, muscular athletes)
Divide body weight by square of ur height
how many adults are overweight or obese in canada
approx 64%
how many kids (5-17) and indg adults are overweight ot obese
kids
- 30%
indg
- 67%
t/f obesity is becoming known as a chronic disease
t
risks of excess body fat
- Obesity reduces life expectancy by up to 14
years; causes 1/10 premature adult deaths - Associated with ↑ risk of CVD and diabetes
- Associated with ↑ risk of many cancers, impaired immune function, diseases of the kidney and gallbladder, bone and joint
disorders, impotence, incontinence, pregnancy
risks, psychological disorders - Also, risks associated with very low weight
what are the types of body fat
essential and risky fat
essential fat
Amount of fat necessary for maintaining bodily functions
* 3% of male weight
* 12% of female weight
* Essential for
reproductive capacity
* Hormonally-determined
* Not associated with
health risk
risky fat
Non-essential
* Visceral or subcutaneous
adipose
* Depends on sex, age, diet, activity
* Mobilized by energy
demand
* Hormonally-determined
apple (android) and pear (gynoid) shape
overweight men tend to have apple
overweight women tend to have pear shape
Subfat in lower body, hips, upper thighs, butt (pear)
Excess visceral + ectopic fat - upper body (apple)
review obesity + diabetes slide
evaluating body weight + composition
- Height-weight charts
- Hydrostatic weighing
- Skinfold measurements
- Circumference measurements
- Electrical impedance
- Scanning (e.g. MRI) methods
- BMI – simplest and most broadly applicable
smart scales
height-weight charts
Range of ideal recommended body weights associated w/ lowest mortality for ppl of certain sex, age, and height - can be highly inaccurate - only provide an indirect measure of body fat
hydrostatic
One of most accurate techniques for analyzing body comp
- Submerged under water and percent body fat is calculated from body density
- Muscle has higher density and fat lower than water so ppl with more fat tend to float and weigh less under water - lean ppl tend to sink and weigh more under water
Bod pod uses air instead of water
- Sits in chamber and computerized pres
skinfold measurements
- Measures thickness of fat under skin
○ Taken at sev sites on body and put into formulas that calculate body fat %s
Accuracy is dependent on expertise of practitioner
circumference measurements
- Wait circum and waist to hip ratio used to measure abdominal obesity and predict health risk
- W waist circum over 40 inches and over 35 inches for men is associated with increased risk for chronic disease
Waist to hip involves measuring the waist and hip diameters, then dividing the waist value by hip value
electrical impedance
- Electrodes attached to body and harmless electrical current is transmitted from each electrode
- Electrical conduction through the body favours path of fat-free tissues over fat tissues
Computer calculates fat %s from measurements of current
scanning (MRI) methods
- Very accurate but expensive
CT, MRI or DEXA
what determines ur weight
energy balance