Flashcards in Nutrition Chapter 10 Deck (43):
What is energy balance?
equilibrium between calories in and calories out
expenditure and intake are the same
weight will stay the same
What is positive energy balance?
more calories in than calories out
weight gain will occur over the long term
What is negative energy balance?
fewer calories in than calories out
weight loss will occur over the long term
What are the four parts of energy expenditure?
basal metabolic rate
thermic effect of food (TEF)
How is the calorie content of a food measured?
in a bomb calorimeter
What is BMR?
basal metabolic rate
minimum amount of energy expended to keep a resting, awake body alive
~ 60-70% of total energy needs
varies between individual
keeps heart beating, body temp. up, respiration, etc.
What is RMR?
resting metabolic rate
easier to measure than BMR
What factors affect BMR?
age, gender, body composition, stresses, environmental temp, nutritional status, hormones, caffeine, smoking, fever, sleep, growth stage
more surface area --> higher BMR
more fat tissue --> lower BMR
more lean muscle tissue --> higher BMR
What is PA?
increases energy expenditure beyond BMR
~ 20-40% of total energy needs
easiest component to control
varies widely among individuals
What is TEF?
thermic effect of food
energy needed to digest, absorb, and metabolism the food you eat
~ 5-10% of energy expenditure
TEF for PRO > CHO > FAT
less energy used to transfer fat to adipose stores
What is thermogenesis?
nonvoluntary physical activity
minimal contribution to EE
How can energy expenditure be measured?
direct calorimetry - measures heat output
indirect calorimetry - measures O2 use
*stable isotopes - doubly labeled water
How many calories do you need?
Estimated Energy Requirement (EER)
determined by 5 variables
5. PA level
What is a healthy body weight?
1. body mass index (BMI)
2. body composition (fat mass:lean mass)
3. distribution of body fat (where?)
4. weight-related medical issues (HPT, Diabetes)
What is BMI?
body mass index
preferred weight to height standard
What are the BMI ranges?
underweight = 40
What are the limitations of using BMI?
does not account for muscle mass
not applicable to: children, adolescents, pregnant and nursing women, people under 5' tall, frail elderly
What is body composition?
a measure of overweight vs overeat
body weight = fat + lean tissue (includes H2O)
how much weight is fat?
8-24% body fat ideal for men
21-35% body fat ideal for women
How is body fat estimated?
fatfold measure - calipers, very imprecise
air displacement plethysmography
*dual energy x-ray absorptiometry (DEXA)
What is body fat distribution?
where the fat is located
measure waist circumference
risk increases if:
>40 inches in men, >35 inches in women
What kind of fat is located around the belly?
visceral fat/intra-abdominal fat/central adiposity/upper body fat
is more dangerous than lower body fat because it effects the organs
more common in men due to presence of testosterone
also encouraged by alcohol intake
What are health risks associated with being underweight?
unable to preserve lean tissue during wasting and medical stresses
not enough estrogen produced --> menstrual irregularities and infertility, osteoporosis, bone fractures
What are health risks associated with being overweight?
diabetes, hypertension, CVD, sleep apnea, respiratory diseases, certain cancers, osteoarthritis, pregnancy complications, gallbladder disease
What percent of obese are metabolically healthy?
being active, even if overweight, is better than being sedentary
How have eating patterns changed to encourage overweight and obesity?
eating more calories overall, not a specific macronutrient
eating away from home more - less control
How can fat cells develop?
adipose cells can increase in size and increase in number
hyperplasia is when they increase in number (divide as they get big)
hypertrophy is when they increase in size
they can shrink after growing, but can't decrease in number
What is fat cell metabolism?
lipoprotein lipase (LPL) promotes triglyceride storage in adipocytes
more fat cells = more LPL activity
as fat cells shrink, LPL remains
loss of body fat signals gene to increase LPL
What are some interrelated causes of obesity?
3. regulation of eating behavior
How is eating behavior regulated?
GO signals - hunger and appetite
STOP signals - satiation and satiety
many things can interfere with signals:
neurotransmitters, neuropeptides, hormones, medications
What is the difference between hunger and appetite?
hunger - physiological drive to eat
appetite - psychological drive to eat
What is the different between satiation and satiety?
satiation - fullness immediately following a meal
satiety - fullness between meals
What are the benefits and dangers of obesity treatments?
Benefits - improve health, prevent and control chronic disease
Dangers - fad diets, weight cycling, psychological problems
What are consequences of weight cycling?
increased risk of premature death and chronic disease, possibly lowers LDL, more likely to regain in around the belly rather than thighs, self-esteem issues
How can genetics impact obesity risk?
account for ~ 40% of weight differences
affects metabolic rate, fuel usage, brain chem
influences fat distribution
thrifty metabolism gene
set point theory
What are risk factors that signal a need to lose weight?
waist circumference, BMI
hypertension, high LDL, low HDL, impaired glucose tolerance, smoking, family history of heart disease
men >= 45 years old, women >= 55 years old
What are the health risks of fad diets?
unsustainable in the long term
restrictive - removing entire food groups or macros
nausea, headache, death
could lead to weight-cycling
Who is a candidate for prescription drug intervention?
BMI >= 30 (obese)
BMI > 27 w/weight related conditions present
all the drugs have side effects!
must include behavior change
Who is a candidate for gastroplasty?
BMI > 40
BMI > 36 w/weight related conditions present
been obese for 5+ years
no history of alcoholism or psychiatric disease
*requires major, lifelong lifestyle changes
What are reasonable ways to treat obesity?
1. control calorie intake
2. participate in physical activity
3. address behaviors and attitudes
What are components of a healthy eating plan?
be realistic about energy intake, emphasize nutritional adequacy, lower energy dense foods, small portions, focus on complex carbs, remember water, choose fats sensibly, watch for empty kcal
What are strategies for including physical activity?
make it a part of daily routine
duration and regularity are important
What are behavior modifications for weight-loss?
breaking the chain, cognitive restructuring, stimulus control, self-monitoring, contingency management