Obesity Flashcards
(85 cards)
1
Q
what is BMI?
- developed by who? year?
- was known as what?
- metric formula? vs imperial formula?
A
international measure of obesity –> body mass index or body mass indicator –> ratio of weight to height
- developed by Belgium statistician Adolphe Quelet (1796-1874)
- was known as Quetelet index
- weight (kg)/height^2 (in meters)
- (weight in pounds * 703)/height in inches
2
Q
what is the name of the index where you take height more into account (height^3)?
A
ponderal index
3
Q
what are the cut-off values for underweight, normal range, overweight, obese 1, 2 and 3
A
UNDERWEIGHT: <18.5
severe thinness: <16
moderate thinness: 16-16.99
mild thinness: 17-17.99
NORMAL: 18.5-24.99
OVERWEIGHT: 25-29.99
OBESE 1: 30-34.99
OBESE 2: 35-39.99
OBESE 3: >40
4
Q
when does BMI not work?
A
doesn’t take into consideration body composition!
- is Herschel Walker –> football player: just does push ups, pull ups and skip rope –> 4% body fat, 33 BMI bc all muscle mass
5
Q
do children also have BMI cut-offs?
A
no! follow a percentile chart! where x-axis is age, and y-axis (2 different scales on right vs left) is BMI!
- check your percentile!
- different charts for boys vs girls
6
Q
what are the generally accepted classifications for BMI and weight status in children and adolescents?
A
UNDERWEIGHT: BMI less than 5th percentile for age and sex
HEALTHY WEIGHT: BMI btw 5th and 85th percentiles
OVERWEIGHT: btw 85th and 95th percentile
OBESE: greater than 95th percentile for age and sex
7
Q
what is the relationship btw obesity and mortality?
- men vs women
A
U or J shaped relationship! NOT a linear relationship!
- unhealthy to be at low BMI and too high BMI –> sweet spot in the middle –> where healthy BMI cut-offs are made!
- men = more J
- women = more U ish
8
Q
how is obesity defined by adiposity? males vs females
can you have 0% fat?
A
- males: 25% body fat or greater
- females: 30% body fat or greater
you CANNOT! - fat in brain, organ lining, cell membrane
9
Q
overweight vs obese definitions
A
OVERWEIGHT
- indicates too much body weight for a given height and frame
OBESITY:
- refers to an overfat level that brings with it increased risks of serious and fatal diseases
*can be overweight without being obese
10
Q
what does epidemiologic measures measure? of which 3 events
A
measures FREQUENCY at which an event occurs!
- injury
- disease
- cause of death
11
Q
what is an incident case?
- ie what can you look at?
A
new occurrences of these events during a time period of interest (ie pandemic)
- health status changes during time of interest! deaths from a certain disease, not injured to injured…
12
Q
trends in obesity prevalence among adults in canada from 2005 to 2017?
- generally
- stratified by age
- by province
A
- gradual increase (from 21% to 27% ish)
- younger adults (18-29) are less likely to be obese than older/middle aged (30-79 yo)
- more prevalent in territories, saskatchewan, newfoundland and labrador, NB –> then manitoba, NS > ontario, qc, alberta > BC
13
Q
define “rate” in epidemiology
A
(number of cases, events or deaths)/population of interest
ie medically attend injuries in school for population of interest
- across some period of time
14
Q
in 2022, how many people & percentage in canada were overweight vs obese?
A
OVERWEIGHT: 10M –> 35%
OBESE: 8.7M –> 30%
15
Q
obesity trends among US adults
- from 1985 to 2023
A
1985: half of states that had data were <10%
- over the years, more states surveyed + more dark blue (10-14%)
- 1989: half of states in 10-14%
- 1991: new color: 15-19%
- 1994: no 10% anymore
- 1996: more than half 15-19%
- 1997: new colour: >20%
- 1999: half of country >20%
- 2001: new colour: >25%
- 2005: only colorado and massachussets in 15-19 –> all others are bigger –> new colours: >30%
- 2011: change colour code au complet –> smaller category is <20%, biggest is >35%
- 2019: add categories of 35-40, 40-45, 45-50, 50+
- 2023: most states 30-40% ish, some states 40-45%
16
Q
increased obesity in US –> similar to which other disease’ trend in US?
A
diabetes!
17
Q
does self-reported or measured BMI report higher BMIs?
A
measured!
*self-reported limitations:
- mostly underreported
- ppl might not weigh themselves, especially as they get heavier, genuinely don’t know their height and weight
- men tend to overreport height
- women tend to underreport weight
18
Q
which age groups have the most increased BMI from 1978 to 2004 in canada? why is it worrisome?
A
- 12-17 –> more than double
fat kid will lead to fat adult - 25-34 –> more than double
- 75+ –> more than double
19
Q
what is sarcopenic obesity?
A
when you have all the metabolic problems of being obese/increased fat but you also decrease in muscle so become frail
20
Q
are women or men more likely to be underweight, normal weight, overweight, obese 1, obese 2 and obese 3 in canada?
A
underweight: women ish more likely
normal weight: women > men
overweight: men > women
obese 1 and 2: similar, no difference
obese 3: women > men
21
Q
are obesity rates increasing in all countries?
A
no! not in Japan and Sweden
- vs increasing in Australia, Brazil, England
22
Q
what are the trends of obesity rates from 18 yo to 75+ yo in Canada?
A
- 18-24 = least
- increasing over middle years/45-65 (peak) –> then decrease (partly bc obese people don’t live that long
23
Q
what might account for differences in COVID mortality from Italy and China?
A
increased prevalence of obesity in older adults in Italy compared to China
+ pandemic: eating for comfort, decreased PA, less pressure, ppl didnt see them
24
Q
how much are the economic costs due to physical inactivity and excess weight?
- trend?
A
P inactivity: 200B ish
excess weight: 200B ish but a bit higher than physical inactivity
- combined: around 460B –> increasing to about 650B $ in US
25
- how to we define optimal body weight?
- how to we determine optimal body weight?
- what are problems associated with concept of optimal weight?
- different depending on goal ish --> weight optimal for health, for appearance, for peak performance!
- ie marathon runner --> take height and weights of all elite olympic finalists
- eating disorders, sports with weight classes
26
what are the 3 compartments of body composition?
- muscle mass
- skeletal mass
- fat mass
+remainder (connective tissue)
27
what are the typical body composition changes from 25 to 55 yo?
- body weight increases by 30lbs (gain 1 lb per year)
- fat mass increases by 45 lbs (gain 1.5 lbs per year)
- muscle mass decreases by 15lbs (lose 0.5 lb per year)
28
what are the 2 main categories of body composition ish? + subcomponents
LEAN TISSUE = metabolically active tissue (LBM)
- muscle
- bone
- connective tissue
- organs
FAT TISSUE
- subcutaneous fat
- internal fat (android obesity)
29
is a hard beer belly good for health? vs jiggly fat?
HARD beer belly = visceral fat
- the worst for health
VS jiggly fat = subcutaneous = less bad
30
what are lab methods (9) vs field methods (3) for measuring body composition?
LAB
- underwater weighing (use archimede's principle: measure weight underwater, calculate density, estimate body fat)
- bioelectric impedance (prof doesn't believe it's good, fat blocks current more than water, muscle...)
- ultrasound (wand)
- x-rays
- MRI (more precise, but very expansive)
- CT
- DEXA
- body pod (for children, no radiation, air displacement)
FIELD
- body mass index
- skinfold measurements
- circumference measurements (ie height to wt ratio)
31
apple vs pear
- which is better?
apple = central fat = storing weight higher = greater risk for metabolic risk
VS pear = store fat below waist --> allows women to handle pregnancy better
32
most field methods (+ what?) for assessing body comp have margin of error of how much?
+/- 4%!
also bioelectric impedance
33
waist/hip ratio
- related to (2)
- how to calculate?
- American Heart association standards for males vs females?
- related to android obesity (central) and internal body fat
- wait circumference/hip circumference
- males: <1.0
- females: < 0.8
34
compare android vs gynoid obesity
- what?, metabolic consequences?
- also visceral vs subcutaneous fat --> hard or jiggly?
ANDROID: mostly fat in upper body --> more health consequences
- apple
GYNOID: mostly fat in lower body: might be obese but less metabolic consequences
VISCERAL: hard fat = bad
SUBCUTANEOUS: jiggly, less bad
35
what type of scan can visualize subcutaneous vs visceral fat?
- what is muscle marbling? good or bad?
CAT scans (or DEXA (?))
- when fat infiltrates skeletal muscle! affects muscle contraction = bad
36
what is cellulite? causes what?
- caused by what ish?
- how to remove cellulite?
cellulite = fat cells --> causes dimpling on skin + fibrous cords btw fat cells break down
- genetic component!
- billion dollar industry! --> creams, wands, leggings...
37
which 2 general categories of factors affect metabolic syndrome?
- what are 8 symptoms of metabolic syndrome?
- overall causes what (2)
- genetic and environmental factors
1. inflammation
2. high BP
3. high TG levels
4. visceral adiposity
5. abnormal vascular response
6. high blood glucose level
7. low HDL-C levels
8. prothrombotic state --> more likely to get clots
- cardiovascular events
- diabetes
38
what are clinical blood glucose levels for active insulin-treated clients?
- NORMAL blood sugar
- PREDIABETIC
- HIGH BLOOD SUGAR (hyperglycemia)
- LOW BLOOD SUGAR (hypoglycemia)
- VERY LOW blood sugar (unconsciousness
- NORMAL blood sugar: 80-100 mg/dL
- PREDIABETIC: 100-120 mg/dL
- HIGH BLOOD SUGAR (hyperglycemia): > 120 mg/dL
- LOW BLOOD SUGAR (hypoglycemia): <70 mg/dL
- VERY LOW blood sugar (unconsciousness): <40 mg/dL
39
- what are 2 other names for metabolic syndrome?
- what is it?
- is the pathology well understood? what are 2 important causative factors?
- syndrom X, insulin resistance syndrom
- constellation of risk factors associated with increased risk of type 2 diabetes and CVD
- each component is complex + not well understood --> central obesity and insulin resistance
40
how to diagnose for metabolic syndrome?
3 or more of these 5 factors:
- abdominal obesity (waist circ)
- TG
- HDL
- BP
- fasting plasma glucose
41
what are the cut-offs to diagnose for metabolic syndrome?
- 2 different cut-offs for each of the 5
1. National cholesterol education program (NCEP-ATPIII)
2 international diabetes federation (IDF)
Abdominal obesity (waist circ):
1. men >102cm women >88
2. men >94cm women > 80cm
- TG >150 mg/dL
- HDL < 40 mg/dL (men), < 50 mg/dL (women)
- BP: > 130/>85 mm Hg
- fasting plasma glucose:
1. >110 mg/dL
2. >100 mg/dL
*TG, HDL, BP; same for 1 and 2
42
what happens to % prevalence of metabolic syndrome as age increases?
increases risk as age increases!
- 60+: over 40% of US adults
- vs 40-59: increase obesity but body can survive/resist negative metabolic consequences
43
which ethnicities are more likely to have metabolic syndrom in Canada?
- indigenous! (women and men)
- south asian (men and women
- euro (more men than women)
- chinese = least of the 4
*chinese: BMI curve shifts left (?)--> need ot be leaner to have healthy BMI
44
which provinces in Canada has the most age-standardized prevalence of diabetes?
Newfoundland and labrador (6.5%) --> Nova scotia (6.1%) --> ontario (6.0%) --> NB, manitoba (5.9%) --> PEI (5.6%) --> NW territories (5.5%) Sask, BC, Yukon (5.4%) --> QC (5.1%) --> alberta (4.9%) --> nunavut (4.4%)
45
relationship btw level of self-reported PA and risk of having metabolic syndrome (graph)
what about if level of fitness is on x axis?
PA: increase PA = decrease risk --> dose response relationship
- increase level of fitness = decrease level of metabolic syndrome
*confounding factors --> smoking, healthy diet, weight...
46
what are 5 big problems linked to obesity?
1. major risk factor for type 2 diabetes
2. risk factor for some types of cancers
3. social, psychological, and financial problems
4. high total C, LDL-C, BP + low HDL-C ---> risk factor for #5
5. major risk factor for coronary heart disease
47
what is the paradox in the US concerning obesity?
50B $ spent on diets, diet products in US + very high number of health club members
but obesity keeps increasing
48
be wary of which weight loss products?
- skin patches, shoe insets
- products concerning ephedra, ephedrine, ma huang
- fat blockers, shrinkers
- fat absorbers, magnets
- diet teas
- contain chromium picolinate, hydroxycitrate, gamma linolenic acid, glucomannan...
- fiber tablets, laxatives
- electrical muscle stimulators for weight loss or body toning
49
energy balance
- positive
- negative
- neutral
POSITIVE:
Caloric consumption greater than caloric expenditure = weight gain.
NEGATIVE
Caloric consumption less than caloric expenditure = weight loss.
NEUTRAL:
Caloric consumption equals caloric expenditure = no weight change.
50
does genetics contribute to obesity?
*study with twins in Laval
*in the EXAM!
yes! not just obese bc you're lazy and a sloth
- more SNPs you have, more likely you are to have obesity
- likely constellation of genes
- twin A and twin B: correlated weight change --> means that genetics has an effect!
HOWEVER, huge variability between pairs of twins, so genetic predisposition plays a role, but people with same DNA usually gain same amount of weight
51
what happened to BMI of pima indians (genetically predisposed to be obese) if they live in Mexico or moved to Arizona?
MEXICO
- worked farm + ate food that they grew
- BMI = 25
ARIZONA:
- much more americanized, sedentary + eat fast food
- men: BMI 31 ish
- women BMI 36 ish
52
can twins have different body compositions if they do different training?
yes! runner is more lean vs weight lifter is more jacked
- environment affects their body!
53
explain figure of what happens to BMI by increasing obesogenic environment for people with
GENETIC OBESITY
STRONG PREDISPOSITION
SLIGHT PREDISPOSITION
GENETICALLY RESISTANT
GENETIC OBESITY
- start with high BMI, slight increase with increasing obesogenic env.
STRONG PREDISPOSITION
- start medium ish, BIG increase
SLIGHT PREDISPOSITION
- start a bit lower than strong, moderate increase in BMI
GENETICALLY RESISTANT
- start a bit lower than slight, no effect of environment
54
what are 2 factors related to the increase of obesity prevalence?
- altered dietary intake! increase in fast-foods restaurants in america
(sale of happy meals alone (3B) is more than total sales revenues for burger kind (2.5B), DQ (2.5B), wendys...)
- increase calories consumed outside of home (ie drive through window) = decrease kcals consumed at home (from 76.9% in 1977 to 64.5% in 1996)
55
which age range to males vs females have the highest mean total energy intake? in canada
males: 14-19: 2440
- 19-30: 2427
then decrease
females: 9-13: 1843
14-18: 1764
then decrease
56
what are 2 things that increased at same time as increase in % overweight and obese?
- calories consumed per capita per day
- number of large-size PORTIONS! introduced --> hugely affects energy intake! --> increase portions = increase energy intake (ie add 50c to make it a bigger size)
57
shifts in food practices in north america (6)
- Fast food consumption
* Reduced frequency of family meals
* Restrained eating, meal skipping
* Consumption of soft drinks-increased
from 27 to 44 gal/y from 1972-2023
* 30,000 products in supermarkets --> increase choices = people more likely to make poor choices
* Increased portion size
58
- difference btw REE and BMR?
- what are the 2 other things that contribute to daily energy expenditure?
- what are 3 PA subdivisions?
REE = resting energy expenditure --> cals burned just lay in bed
BMR = basal metabolic rate --> measure expired gasses at rest, proxy for REE, lower
REE + thermogenic effect of food + PA
1. PAL: toatl PA expressed as ratio of RMR
2. NEAT: non-exercise activity thermogenesis
3. exercise energy expenditure due to purposeful PA
TEE = REE + TEF + PA
59
what are the typical % of each component of TEE?
- RMR: 60-75% --> can't control, genetics
- TEF: about 10%
- thermic effect of activity --> 15-30% --> but very variable! we can control! --> could exceed % of RMR for high level athletes
60
what happens to RMR, TEF and TEE after
DISUSE EFFECT
PA/EXERCISE EFFECT
DISUSE EFFECT
- all 3 will decrease, except Thermic effect of meals will decrease OR stay same
PA/EXERCISE EFFECT
- RMR and TEF: increase or stay the same
- TEE will increase!
61
what happens to RMR post obesity/weight loss?
- ie what happens if someone loses 20kg?
- RMR will decrease!
- 25% of tissue lost is muscle during weight loss --> ie 1 in 4 lbs lost is from fat free mass --> impossible to just lose fat
- in general, each kg of weight loss = 20cal/day drop in RMR
- 20kg loss will reduce RMR by 400 cal/day --> bc less of that person to sustain
*can't remain weight stable if keep eating same level of cals during weight loss
62
prolonged caloric restriction will lead to what in terms of metabolism?
- similar results seen after what?
- reduces resting metabolism! bc body tries to save itself = protection
- severe restriction can reduce RMR by 45%
- perhaps, regular exercise results in a similar self-preservation type of stress response (?)
63
obesity epidemic:
- increase ____________ + decrease ______________ = increase ____________
increase energy intake (likely, just a little every day) + decrease in energy expenditure = increase weight!
64
- describe graph with increasing TV watching vs sum of 4 skinfold (objective measure for what?)
why?
sum of 4 skin folds = objective measure of adiposity
- girls have a higher sum of 4 skinfolds than boys across all 3 categories of daily TV watching
- <2h < 2-3h < 4+h --> each category is significantly leaner than the next
- screentime = hazard to waistline bc low E state + prompted to eat (snacking + all the ads about food)
65
relationship btw hours of TV watched and caloric intake in US children. graph?
- as hours TV watched increased, total caloric intake also increased!
66
what % of US adults are couch pototoes (no activity) vs irregular activity vs regular sustained activity (ie enough PA for health benefits)
NO ACTIVITY: 30%
IRREGULAR ACTIVITY (some PA but not enough to get health benefits): 45%
REGULAR SUSTAINED: 25%
67
what are the 4 characteristics for exercise prescription to help obese increase PA?
- vigorous activity
- sustained/uninterrupted
- 3-5days a week
- sophisticated --> requires exercise physiologist to do some testings
68
what is a funny definition of exercise?
the art of converting big meals and fattening snacks into back strains and pulled muscles by lifting heavy things that don't need to be moved or running when no one is chasing you
69
is there a linear relationship between activity level and health benefits?
no! a curvilinear relationship!
- biggest improvement of benefits is getting the sedentary people to be moderately active.
- after that, curve almost flattens out: not much excess benefits if extremely active
70
What are 2 patterns of PA over 24h that have the same area under the curve? vs ________
- sedentary: most day: energy expenditure under 2 METS
1) leisure-time exercise: essentially same as sedentary but goest for a walk/run during lunch time (EE up to 10 METS) --> baseline a bit higher than sedentary
2) lifestyle exercise: teach patients to look for opportunities to increase EE (ie get off bus 1 stop earlier, take stairs) --> little spikes of EE up to 4 METs, about 8 times per day --> SAME area under curve than leisure-time exercise
71
study on aerobic exercise vs lifestyle exercise --> who lost the most weight?
- changed in serum cholesterol?
- total treadmill time in max step test?
- weight change after 68 weeks?
- both had almost identical weight loss!
- both had similar improvements!
- similar improvements in both groups
- lifestyle lost around 8kg after 16 weeks + pretty much plateaus and maintains lost weight! bc continued healthy lifestyle habits VS aerobic also lost 8kg, but regained a bit of weight up to 68 weeks
72
compare the 3 tertiles of people who met or not the Surgeon general guidelines. who had the most weight change?
- least active tertile gained weight!
- second active tertile about the same, a bit weight loss but regained it
- most active tertile lost most weight!
73
what is the name of the equation to calculate BMR?
- what do we plug into the formula?
- better than what?
- what factor is omitted? would that result in higher bMR or lower?
- conclusion?
Harris Benedict Equation
- weight in kg, height in cm, age in years
OR weight in lbs, height in inches, ages in years
- better than calculating calories only based on body weight
- lean body mass (and thus ratio of muscle to fat body has) is omitted --> leaner bodies need more calories than less leaner ones
- conclusion: equation is very accurate in all but the very muscular (will underestimate cal needs) and the very fat (will over-estimate cal needs)
74
by which factor do we multiply BMR for
- SEDENTARY
- LIGHTLY ACTIVE (__-___ DAYS/WK)
- MODERATELY ACTIVE (__-___ DAYS/WK)
- VERY ACTIVE (__-___ DAYS/WK)
- EXTRA ACTIVE (__-___ DAYS/WK)
SEDENTARY:
- BMR x 1.2
LIGHTLY ACTIVE (light exercise 1-3 DAYS/WK):
- BMR x 1.375
MODERATELY ACTIVE (mod exercise 3-5 DAYS/WK):
- BMR x 1.55
VERY ACTIVE (hard exercise 6-7 DAYS/WK):
- BMR x 1.725
EXTRA ACTIVE (very hard exercise or physical job or 2x training):
- BMR x 1.9
75
what are total body weight, body fat and fat-free body mass changes for
ONLY DIET CHANGES
ONLY EXERCISE CHANGES
BOTH DIET AND EXERCISE
- whats the best option!
- which is generally the poorest prescription for obese people? (other graph)
ONLY DIET CHANGES
- BW: -11.7
- Body fat: -9.3
- muscle mass: -2.4 (NOT good!)
ONLY EXERCISE CHANGES
- BW: -10.6
- Body fat: -12.6
- muscle mass: +2 yay!
BOTH DIET AND EXERCISE
- BW: -12
- Body fat: -13.1
- muscle mass: +1.1
BEST option would be a combination of both! most bw loss, with a bit of muscle mass gain!
vs only diet changes, also lost a lot of muscle mass = bad
- exercise = poorest! --> another figure shows that exercise has lowest weight change, vs diet and diet&exercise had similar weight changes
76
meta-analysis of 1970s, 1980s and 1990s --> do they show big weight change after exercise prescription?
- solution!
- nope! -0.09, -0.09 and -0.06 kg body mass per week = really not a lot
- solution: need to combine with decrease calorie intake!
77
- lose 1lb = ______ calories
- so how to lose weight (3 ways)
1 lb = 3500 calories (but doesn't hold true for everyone, depending on genetics)
a) eat 500 less cals per day for 1 week = lose 1 lb
b) eat a bit less and increase PA
c) eat same but increase a lot PA
78
what may be the key role of PA in weight management for obese people?
maintenance!!
- those who are active maintain a constant desirable body composition
79
what are 4 guidelines for managing your weight?
- lifestyle behavior change: diet + PA --> look at what led you to gain weight and change those
- psychological and behavioral considerations --> triggers, what led to relapse
- caloric intake
- caloric expenditure
80
what are 6 ways for behaviour modifications? (thing strategies)
- self-monitoring: diaries: recording what you eat honestly
- stimulus control: identify circumstances that stimulate eating
- reward reinforcement: formal rewards (ie new workout clothes)
- nutrition education (concept of cals)
- physical activity
- cognitive restructuring: counter negative thoughts, set reasonable goals
81
what are 4 weight loss misconceptions?
- quick fixes
- fad diets (always a new book)
- cellulite
- spot reduction
82
what did the study on tennis players show about fat/muscle mass on dominant vs non-dominant arms?
- difference in muscle mass
- BUT skinfold similar on both dominant and non-dominant arms = fat mass similar
83
what is the basic theory to lose weight?
- vs gain weight?
- to lose weight, you must expend more calories than you consume. you can do this by consuming fewer calories or a combination of diet and exercise
- to gain 1 lb (0.45 kg) per week, eat about 400-500 more calories per day than you expend (+ enough protein), and continue to exercise regularly and include weight training to ensure that the gain is in lean weight
84
what happened to our weight vs our perception of ideal in 1950 vs 2019?
1950:
- weight and perception of ideal were pretty close. weight a bit higher
2019:
- weight increased and perception of ideal decreased a lot = now a huge gap btw the 2
85
what are types of disordered eating?
- more prominent in (3)
- what are 3 risk factors?
- what can we do as exercise physiologists?
- bulimia (binge-purge syndrome), anorexia nervosa, orthorexia (preoccupation with healthy foods and perfect eating/exercise)
- more prominent in females (but males can also have it), athletes and vegetarians
- genetic, environmental (appearance sports, gymnastics, diving, weight classes), psychological
- a bit out of our scope --> refer to specialist!
