Midterm 2 Section 1 Flashcards
types of energy
capacity to do work: heat, mechanical and electrical
percentages of energy expenditure
basal metabolism (50-65%)
thermic effect of food (5-10%)
physical activity (25-50%)
basal metabolism =
activities to keep the body functioning to maintain homeostasis
factors that affect BMR
fasting/starvation/malnutrition - lowers BMR
lean body mass, thin tall people and some life stages (children, adolescents and pregnancy) - increases BMR
Conditions for measuring BMR
If conditions are not met, what are you measuring?
indirect calorimetry used
relaxing, reclining, awake, thermo-neutral environment, post absorptive state, and no heavy physical activity in last 12 hours
RMR - resting metabolic rate
physical activity =
exercise =
voluntary muscle movement
structured voluntary movement with goal of improving fitness parameters
what is the 3500 rule?
Why is it not accurate?
where does the rule come from?
1 lb of fat = 3500 kcal
water loss first, adaptation to restriction
metabolic adaptation - BMR lowers in response
gender differences
1lb/454g body fat is 87% fat
Why is EER based on EAR not RDA?
accounts for weight, height, age, gender, and physical activity giving +/- 20% error
avoid people over consuming
EER = TEE
Estimated Energy Requirement = Total Energy Expenditure
Men: 662 - (9.53 x years) + PA x [(15.91 x kg) + (539.6 x meters)]
Women: 354 - (6.91 x years) + PA x [(9.36 x kg) + (726 x meters)]
PA values sedentary - very active
1.00- 1.39 sedentary
1.40 - 1.59 low activity
1.6 - 1.89 active
1.9 - 2.5 very active
definition of hunger and influences
physiological influences: empty stomach, gastric contractions, absence of nutrients in small intestine, endorphins
sensory influences: endorphins triggered by sensory input of food which enhances desire
hunger produces impulse to eat
size and composition of meal
cognitive influences on why we continue to eat
social stimulation, perception of hunger or awareness of fullness, favorite foods or foods with special meaning, time of day, abundance of food
satiation definition and influences
definition - short term feeling of fullness
post-ingestive influences: food in stomach triggers stretch receptors
nutrients in small intestine elicit hormones (like cholecystokinin which slows gastric emptying)
definition of satiety and influences
long term feeling of fullness
post-absorptive influences: nutrients in blood signal to brain that they are available
decreasing nutrients in blood signals hunger again
3 areas that influence appetite control
hormones that influence appetite
both psychological and sensory influenced
cognition (knowing what is good or bad for us), homeostasis (hunger cues) and reward systems (strong, craves foods we like for quick energy)
ghrelin, insulin, leptin, GLP-1, and serotonin
leptin function, production and regulation
function: suppresses appetite and food intake between meals
production: hormone made by adipose tissue, some produced in stomach
regulation: negatively regulated, increased adipose tissue stimulates leptin (decreases appetite)
decreased body fat suppresses leptin production
leptin resistance
body becomes desensitized to leptin signaling
normally high leptin signals hypothalamus to decrease food intake and increase energy expenditure
ghrelin function, production and regulation
Function: increases food intake by signaling hunger, prepares for consumption by increasing gastric motility and gastric acid secretion
Production: produced in the GI tract, especially the stomach
Regulation: levels are highest before meals when hungry and lowest after
satiating foods
protein - amino acids sensed by the brain and has a high thermogenic effect
fat, dietary fibre, water and puffed up with air
BMI definition
classifications
kg/m^2
definition: BMI is a cheap, easy and available generalized screening tool to categorize people into weight related risk categories
classifications: underweight < 18.5, healthy 18.5 - 24.9, overweight 25.0-29.9, class 1 obese 30-34.5, class 2 35-39.5, class 3 > 40+
normal weight gives the least health risk
higher BMI for people over 65
healthy BMI from 22-27 to act as protective reserves for injury and illness
limits of BMI
does not distinguish body comp (muscular vs over fat)
no reference to where fat is
ethnicity differences ignored
level of health risk from other factors (smoking, family history…etc)
definition of healthy body weight
a weight that does not increase risk of disease
fat distribution and types
subcutaneous vs visceral (central obesity) vs ectopic
android body fat distribution - apple shape, increased fat in chest and abdomen
gynoid body fat - pear shaped, increased lower body fat, lower risk of disease compared to android
visceral fat indication waist circumference
men: >= 102 cm/40”
women: >= 88cm/35”
ectopic fat
fat that accumulates in organs such as heart, liver, pancreas and muscles
women have what percent more body fat than men at the same BMI?
BMI to percent body fat BMI 18.5, 30 and 40
12% more
18.5 BMI –> 12-19%/25-32% body fat
30 BMI –> 27-32%/40-44% body fat
40 BMI –> 34-38%/46-49% body fat
health problems associated with overweight and underweight
overweight: type II diabetes, dyslipidemia, hypertension, coronary heart disease, gallbladder disease, obstructive sleep apnea, cancer
underweight: undernutrition, osteoporosis, infertility, immunoincompetance
stages of fat cell proliferation
during growth fat cells increase in number
increased energy intake than expenditure, fat cells grow in size
after fat cells have enlarged (20x original size), increase in # again
with fat loss cells shrink in size but not number
fat cell hyperplasia definition
fat cell hypertrophy definition
increased replication rate
increase in cell size
liposuction weight gain side effects
new fat cells can develop again and as well as in weird places like ankles and wrists
LPL in obese people
higher LPL for hydrolyzes triglycerides passing in bloodstream for fat deposition
LPL is higher in women in breasts, hips and thighs
LPL is higher for men in abdomen
set point theory
body strives to achieve homeostasis, hypothalamus makes adjustments to return to set point of weight
BMR slows when food intake decreases, adaptive energy expenditure
leads to yo-yo dieting
US vs. Canada BMI categories
> 40 in US, >35 in Canada is clinically severe
biggest loser study
began with DEXA scan and indirect calorimeter
of the 14, only 1 kept weight off after 6 years
Despite regaining weight, after severe weight loss RMR remains decreased
Suggests the body adapts to significant weight loss
shrinking fat cells produce less leptin. by end of competition, contestants were constantly hungry and thyroid had slowed
none of this rebounded after drastic weight loss
weight regain occurred easily despite eating less than ever
metabolic adaptation
if energy is restricted and there is weight loss, hypothalamus will direct metabolism to maintain energy reserves (slow metabolism and energy expenditure)
weight bias definition
examples
negative attitudes, beliefs, judgements, stereotypes and discriminatory acts aimed at individuals because of their weight
doctors responding negatively to patients, lack of access to appropriately sized medical amenities, prejudice from coworkers, stigmatized media
weight bias contributes to weight gain how?
people believe the bias and that being overweight is a moral failing, it is stressful, increasing eating induced by increased cortisol, increases weight gain and the cycle continues,
Obesity Canada 2020 Clinical practice Guide positives and negative
creating guidelines for healthcare practitioners to address weight bias
focuses on improving health and well being, rather than focusing just on weight loss
identifies obesity as a chronic disease which calls for multidisciplinary treatments
no mention of food landscape
overweight and obesity stats
steady increase of obesity (all classes, especially 2 and above) since 1990
overweight category has remained consistent
due to decreased levels of physical activity, epigenetics and increased processed food intake
definition of obesity
complex disease in which abnormal or excess body fat impairs health
steps in the patient journey in obesity management
1) ask permission to discuss it
2) assess their story (goals and severity)
3) nutritional therapy, exercise and other referrals (surgery, psychologist, meds)
4) agree on goals
5) assist with barriers and drivers
non weight related goals
improved blood glucose control, decreased blood pressure, blood lipids, and increased physical fitness
health at every size, no diet approach, no counting kcal, healthy eating, physical activity, mindful eating
protein intake during weight loss
increased satiety, protects lean tissue, 1.2-1.6 g per kg body weight or 35% of energy
high GL ultraprocessed foods relating to obesity
increased fat deposition in the body resulting from hormonal response to high glycemic load/hyperpalatable diet drives positive energy balance (eat more and gain more)
people eat less unprocessed foods at one time than ultraprocessed
physical activity advantages for weight loss
increased metabolism, improved body comp, increased health benefits, reduced appetite after exercising, stress reduction
types of bariatric surgery
complications
candidates
sleeve gastrectomy, gastric bypass, duodenal switch
infections, nausea/vomiting, dehydration, nutrient deficiencies, psychological problems, reduction of immune system
no metabolic adaptation as seen with weight loss
with BMI over 40 or over 35 with an obesity related disease
adjustable gastric band not accepted in Canada
sleeve gastrectomy
2/3 stomach removed leaving sleeve/tube behind
affects metabolically active tissues and hormones
produces smallest weight loss
gastric bypass
restrict stomach to smaller size (from football to egg sized) using a band (nothing removed), and reconnect SI to bypass first part
middle weight loss effects
reversible procedure if necessary
risk of malabsorption of nutrients
duodenal switch
sleeve gastrectomy + bypassing 80% of SI
risk of malabsorption of nutrients
largest weight loss as a result
very invasive, only for BMI over 70
Orlistat
AKA Xenical
inhibits pancreatic lipase, blocks fat absorption by 30%
side effects: gas, frequent bowel movements, reduced absorption of fat soluble vitamins
