Section 3-2: Energy Balance and Weight Management Flashcards
1
Q
BMI: underweight
A
<18.5
2
Q
BMI: normal
A
18.5 - 24.9
3
Q
BMI: overweight
A
25 - 29.9
4
Q
BMI: obese
A
> 30
5
Q
Globesity
A
The whole world is going obese
- developed counties: poor is fat
- developing counties: rich is fat
6
Q
__% of Canadians are overweight or obese
A
60
7
Q
Consequences of obesity (6)
A
- Diabetes
- CVD
- Cancer: colon & breast
- Joint disorders
- Gall bladder disease
- sleep apnea
8
Q
Which type of men respond better to prostate cancer treatment?
A
Lean, fit men
9
Q
Which common cancer is not linked to obesity?
A
Prostate
10
Q
Steps of cancer
A
- normal
- single mutated cell (reverse differentiation)
- small tumour
- large tumour
- malignancy
- metastasis
11
Q
Cancer is a disease characterized by ________
A
a series of genetic mutations
12
Q
Characteristics of cancer cell
A
- Un-differentiated
- Proliferative: cannot respond to stop signals
- Cannot repair damaged DNA
- Resistant to apoptosis
13
Q
Cancer cells secrete ____, which are ____ factors that promote cell growth
A
insulin & estrogen;
growth
14
Q
Why does cancer secrete insulin?
A
- stimulate cell growth
- suppress apoptosis
15
Q
Why does cancer cells secrete estrogen?
A
- growth of breast tissue
- post-menopause: stimulate growth of breast tumour
16
Q
what form of estrogen is damaging to post-menopausal breast tissue?
A
free (unbound to SHBG)
17
Q
Adipose tissue is a source of ___
A
estrogen
18
Q
What % of people to attempt to lose weight fail?
A
90%
19
Q
why is body weight important to health?
A
- unhealthy body weight = increased health risks
2. weight stigmatization
20
Q
Basal metabolism = ___% of TEE
A
60-75
21
Q
Voluntary activity = __% of TEE
A
15-30
22
Q
Thermic effect of food / diet-induced = __% of TEE
A
10%
23
Q
which component of TEE changes depending on how active you are?
A
- activity
- basal metabolism
24
Q
TEE
A
total energy expenditure
25
Steps of cellular metabolism:
1. glycolysis / B-oxidation / deamination
2. TCA
3. electron transport chain
26
which food has the highest TEF? lowest?
High -> low
| proteins > carbs > fats
27
how much glucose do we store "just in case"?
24h supply
28
how much TG do we store "just in case"?
57 day supply
29
FA from diet is stored as...
TG
30
stored TG reflect ___ composition of the diet
FA
31
How is energy expended in the body?
1. cellular metabolism
2. TEE: maintain life, move body, absorb food
3. extra energy (positive energy balance) stored as dietary fats
32
what can be made into TG?
- glucose (minor)
- AA (minor)
- Fatty acids (major)
33
what is used to measure amount of calories in food?
bomb calorimeter
34
EER
estimated energy requirement
35
EER variables
- gender
- age
- PA
- weight (kg)
- height (m)
36
Lean tissue is defined as...
- fat-free mass (including bone)
| - EVERYTHING but fat
37
Which (age) group has the most body fat? The least?
Most: old, women
Least: adult men
(Babies are somewhere in between)
38
Sacropenia
loss of muscle mass with aging
39
Most common tool for assessing healthy body?
BMI
40
Healthy body weight depends on...
- weight
- % body fat
- location of fat
41
which location of fat is dangerous?
visceral fat (between abdominal muscle and organs)
42
limitations of BMI
- not perfectly correlated with % body fat
- very lean body = high BMI (athletes)
- cannot be used for pregnant / lactating women
43
How are BMI limitations overcome?
used in combination with waist circumference
44
High visceral fat indicates...
high risk for diabetes & heart disease
45
why is visceral fat more harmful than fat in other areas?
- surround organs
- tend to release a lot of FFA → diabetes
- release proteins that leads to inflammation
46
Apple shape vs. pear shape (in terms of fat distribution)
apple: high visceral fat
pear: high subcutaneous fat
47
gold standard for measuring visceral fat
MRI
48
waist circumference measurement correlates well with ____ measurements
MRI
49
subcutaneous fat
fat between abdominal muscles and skin
50
Health Canada vs. Canadian Medical Association cut-offs for waist circumference
CMA: set cut off lower (more strict)
HC: gives range
51
waist circumference cut off between different groups
men > women
| white people > asians
52
how is a healthy body weight assessed?
- BMI
| - waist circumference
53
Mechanisms for regulating body weight
1) hunger
2) satiety
3) satiation
54
satiety vs. satiation
satiety: feeling full after a meal → determines when next meal will happen
satiation: feeling full during a meal → determines when meal ends
55
Obesity genes regulate...
- food intake
- energy expenditure
- fat metabolism
56
Set-point theory / Adaptive Thermogenesis
There is a genetically pre-determined body weight (body tries to keep the same weight)
57
```
Twin study (Laval University): correlation between obesity and genetics
→ result?
```
identical twins who were fed the same diet & had same physical activity did not gain similar amount of weight
- very wide range
- adaptive thermogenesis & metabolism was different in different people
58
Hormones that stimulate hunger
Ghrelin
59
Ghrelin is secreted by...
stomach
60
Functions of ghrelin
stimulate eating at set times
61
high serum ghrelin = (what time)?
before a meal
62
low serum ghrelin = (what time)?
after a meal
63
hormones that supress hunger
- CCK
- Peptide PYY
- GLP-1
64
1 drug used to treat diabetes mimics the action of ___ (hormone). Why?
GLP-1
- stimulate insulin release
- suppresses hunger → weight loss of diabetics
65
Hormone differences in lean vs. obese people
Obese:
- ghrelin levels do not decline as much after meals
- OVERALL ghrelin levels are lower, but the CHANGE is less
- GLP-1 found in lower levels
66
Short-term regulation of food intake is done by...
```
Based on food;
Hormones
- ghrelin
- CCK
- Peptide PYY
- GLP-1
```
67
long-term regulation of food intake is done by...
Based on amount of adipose tissue we have;
Hormone:
- leptin
- insulin
68
Leptin is secreted by ___ to ___
adipose tissue → blood
69
leptin levels are directly proportional to...
amount of adipose tissue
70
leptin acts on ____
hypothalamus
71
purpose of lectin
regulate food intake
- more leptin = less food intake
- less leptin = more food intake
72
what is "leptin resistance"?
less leptin = INTENSE hunger
| more leptin = small signal to stop eating
73
why is leptin a problem during weight loss?
lose weight = less leptin = hungry
leptin resistance goes down = more sensitive to hunger
74
Leptin resistance goes up =
more resistant = less sensitive to hunger
75
leptin resistance goes down =
less resistant = more sensitive to hunger signals sent by leptin
76
Insulin acts on...
hypothalamus
77
evidence that insulin suppresses food intake
type I diabetes = low insulin = always every hungry
78
lean vs. obese: insulin
obese people have more insulin
| - high risk for developing insulin resistance (can't sense stop signal)
79
Genetic contribution to obesity
1) thrifty metabolism
| 2) adaptive thermogenesis
80
what gene contributes to thrifty metabolism?
- no single gene
| - combination of genes alter metablism
81
adaptive thermogenesis can alter energy expenditure up to...
250 kcal
82
Mechanisms used by adaptive thermogenesis
1) futile cycling
| 2) uncoupling of ETC from cellular respiration
83
futile cycling
opposing metabolic pathways happen at the same time
84
uncoupling of ETC from cellular respiration
- produce heat instead of ATP
| - occurs in brown adipose tissue (most adult human adipose tissue is white)
85
Adaptive thermogenesis in fat vs. skinny people
fat person weight loss: cause BMR to go down more than skinny people
fat person gain weight: cause BMR to go up less than skinny people
86
brown adipose tissue can be found at ___. Why do we have it?
neck area;
| lots of mitochondria →meant to conserve heat
87
what happens to BMR when we lose weight?
goes down
88
NEAT
non-exercise activity thermogenesis
- walking
- standing
- sitting
89
NEAT in lean vs. obese individuals
Obese people walk & stand less than lean individuals
90
Units: NEAT
kcal / kg body weight
91
Why are people getting fatter?
- genes (prevent starvation)
| - lifestyle (obesogenic environment & sedentary behaviour)
92
Clinical practice guildlines for treating obesity
- reduce weight by 10% over 6 months
- slow weight loss to avoid muscle loss & adaptive thermogenesis
- avoid weight cycling
93
Benefits of reducing weight when obese?
improve serum lipids, BP, blood glucose
94
What is a healthy amount to lose?
0.5-1 kg/week (cutting 500 - 1000 kcal / day)
95
Is a weight loss treatment effective? Testing should be at least _____
2 years
96
Most people can keep their "healthy, weightloss" diet for how long?
3-6 months, before rebounding
97
modest weight loss of ___% of body weight is beneficial
5-10
98
Lifestyle modifications used to treat obesity
1) nutrition: eat less
2) PA: 30 min every 3-5 days/week
3) CBT
99
CBT used for weight loss: what is it used for?
used to promote changes in behaviour
- new eating habits
- social support
100
CBT for weight loss: process
ABC:
1) Anecedents (cues that lead to behaviour)
2) behaviour
3) consequence
101
1 lb adipose tissue = ___ kcal
3500
102
composition of adipose tissue
80% fat vs 20% water
103
Calculation: how many lbs of fat would be loss if you ate 7000 kcal less per month?
1 lb fat = 3500 kcal
7000 / 3500 = 2 lbs fat loss per month
(actual value is lower due to adaptive thermogenesis)
104
units: energy density
kcal/g
105
inducing satiation & satiety depend on...
how the food fills the stomach (does not depend on kcal!)
106
Do you want to eat low // high energy dense foods?
low (kcal/g)
- not dense in kcal
- high in amount (g)
107
do you want to eat low // high nutrient dense foods?
high
108
Options if weight loss is not working
1) pharmacotherapy (drugs + lifestyle change)
| 2) Bariatric surgery
109
when should pharmacotherapy be used?
if BMI > 27 + risk factors OR BMI > 30
110
When should bariatric surgery be used?
If all else fails!
| BMI > 35 + risk factors OR BMI > 40
111
orlistat
drug used to treat obesity
112
mechanism of orlistat function
Inhibit triglyceride digestion by lipase
| - TG lost in feces
113
Gastric bypass is ____. It works because ____
reduce stomach size & bypass portion of small intestines;
- less absorption of food
- feels full faster
114
Complications of gastric bypass
- micronutrient deficiencies
- dumping syndrome (food enters small intestines too fast)
- meals must be small & eaten very slowly
