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42 Cards in this Set
- Front
- Back
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Basics of Energy Balance
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people continuously expend energy
Energy in=Energy out 3500 calories = 1 pound of fat |
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Bomb caloriemeter
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used to measure energy in food, by measuring heat released this is called Direct
overestimate of energy in food |
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indirect calimetry
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measure the amount of oxygen consumed
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Hunger
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physiological need for food, chemical messengers act on the hypothalamus on the brain giving you the sensation of hunger
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Appetite
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reaction to seeing or smelling food
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satiatition
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signal to stop eating
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satiety
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signal telling you were not ready to eat again
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Diet effects on satiety
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protein suppresses hunger
fat stimulates appetite higher fat=lasting satiety |
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Neuropeptide Y
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causes you to want high carb foods; initiates fat stores, pushing you toward weight gain
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Ghrelin
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secreted by stomach cells; stimulates appetite; promotes energy storage
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leptin
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supresses appetite; increases energy expenditure
when given to people there is no effect because most people make plenty of leptin |
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Energy Out
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heat is a byproduct of metabolism
we only capture 40% of energy in our diet the rest is lost as heat |
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thermogenesis
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the bodys generation of heat; a way to measure energy expenditure
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Categories of Energy Expenditure
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1) basal metabolism- makes up the vast amount of energy expenditure
2) Physical Activity 3) thermic effect of food 4) Adaptive thermogenesis |
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Basal Metabolism
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energy needed to maintain life when a body is at complete digestive physical, and emotional rest
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Basal Metabolic Rate (BMR)
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measured rate of energy used for metabolism under theses specifications:
1) 12 hour fast 2) restful sleep 3) no physical activity or emotional excitment skyrockets in first 2 years of life goes up a little during puberty and then declines rest of your life |
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Resting Metabolic Rate (RMR)
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Less strict, but similar to BMR; usually a bit higher than BMR
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Factors that affect the BMR
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age- lean mass diminishes with age, slowing the BMR
Height- In tall thin people the BMR is higher Growth- in children and pregnant women the BMR is higher Body composition (gender)- the more lean tissue the higher the BMR, the more fat tissue the lower the BMR Fever- fever raises BMR Stresses - raise the BMR |
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Factors that affect the BMR continued
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Environmental temperature- Both heat and cold raises the BMR
Fasting/Starvation- lowers the BMR Malnutrition- lowers the BMR Hormones (gender)- the thyroid hormone thyroxin,for example, can speed up or slow down the BMR. Premenstural hormones slightly raise the BMR Smoking- Nicotine increases energy expenditure Caffeine- Caffeine increase energy expenditure Sleep- BMR is lowest when sleeping muscle is more metoballically active than fat more lean mass equals more calories burned when your doing nothing |
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Physical Activity
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voluntary movement of skeletal muscles and support systems
most variable and most changeable component of energy expenditure |
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3 things that affect how many calories burned during physical activity
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1) how much muscle mass on the body
2) body weight 3) the activity itself |
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Thermic effect of food
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an estimation of the energy required to process food
makes up 10% of your calories |
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Adaptive Theromogenesis
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adjustments in energy expenditure related to changes in environment and to physiological events; this is difficult to account for
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Factors that influence Energy Requirements
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1) Gender
2) Growth 3) Age 4) Physical Activity 5) Body Composition and Size |
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Body Composition
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Proportions of muscle, bone, fat, and other tissue that make up a persons' total body weight
body weight= fat + lean tissue (including water) |
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Fat distribution
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men get intra-endominal fat which is commonly associated with many chronic diseases, this fat is around the organs
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Body Mass Index (BMI)
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BMI= Weight(kg)/Height (m)^2
BMI 18.5 to 24.4 = healthy BMI 25.0 to 29.9 = overweight BMI greater or equal to 30= obese |
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BMI and Mortality
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BMI can Predict Mortality
higher BMI = shorter life |
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Other measure of Body composition
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Waist Circumference - great than 35' for women and greater than 40' for men usually indicates risk for chronic diseases
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Methods used to Assess Body fat
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fatfold measure
Air displacement plethysmography Hydrometiometry Dual Energy X-ray absorpistromy Bioelectracal impedance |
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Eating Disorders Paper
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most susceptible groups- dancers, gymnasts
risk factor-mental disorder The hallmark of Anerexia- is refusal to mantain weight at 85% of body weight bulimia- binging then purging |
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Diagnostic criteria for Anorexia Nervosa
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1) Refusal to maintain body weight at or above a minimally normal weight for age and height
2) Intense fear of gaining weight or becoming overweight, even though patient is underweight 3) Disturbance in the way in which one's body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight 4) Amenorrhea in postmenarchal females- the absense of periods |
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Diagnostic Criteria for Bulimia Nervosa
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1) recurrent episodes of binge eating
2) Recurrent inappropriate compensatory behavior in order to prevent weight gain, such as self induced vomitting; misuse of laxitives, diruetics, enemas, or other medications; fasting ; or excercising excessivly 3) The binge eating and inappropriate compensatory behaviors both occur on average at least twice a week for three months 4) self evaluation is unduly influenced by body shape and weight 5) the disturbance does not occur exclusivly during episodes of anorexia nervosa |
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comparison of features of Anorexia Nervosa and Bulimia Nervosa
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History and symptoms of Anorexia Nervosa:
Amenorrhea, constipation, headaches, fainting, dizziness, fatigue, cold intolerance Of Bulimia Nervosa: Bloating, fullness, lethargy, GERD, abdominal pain, sore throat Physical Findings of Anorexia Nervosa: Cachexia, acrocyanosis, dry skin, hair loss, bradycardia, orthostatic hpotension, hypothermia, loss of muscle mass and subcutaneous fat, lanugo of Bulumia Nervosa: Knuckle calluses, dental enamel erosion, salivary gland enlargement, cardiomegaly |
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Physiology of Obesity
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Fat cell formation
adipocyte (fat cell) metabolism 1) have lots of lpl 2) breakdown of fat differs in different parts of the body 3) LPL activity increases as you lose weight, making the more effecient at storing fat |
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Fat Cell development
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1) During growth, fat cells increase in number
2) when energy intake exceeds expenditure, fat cells increase in size 3) when fat cells have enlarged and energy intake continues to exceed energy expenditure, fat cells increase in number again 4) with fat loss, the size of the fat cells shrinks, but not the number |
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Causes of Obesity
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overeating - portion sizes; cheap food; convience
physical inactivity - technology; unsafe environments; jobs that don't require physical labor; busy work schedule; p.e not required at some schools set point theory - your body will adjust to maintain a certain weight regardless of what you do (decrease in BMR) Genetics- satiety signals (Ghrelin, Leptin), uncoupling proteins ( Brown adipose tissue (Bat)) |
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2 types of Body fat
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white adipose tissue - store fat
Brown adipose tissue- metabolizes energy, but doesnt store it, just releases heat ex) hybernating animals |
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Uncoupled proteins
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BAT goes to uncouppled reactions
more uncoupled proteins equals higher BMR; less efficient; more resistant you are to weight gain less uncoupled proteins equals more likley to gain weight |
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Common interventions to obesity
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fad diets - most emphasize one thing; work but can't maintain that lifestyle long term
over the counter drugs- ex) phenylpropanalalaine (supresses appetite, associated with irregular heartbeat and hypertension, kidney failure) supplements gimmicks ex) cellulite- you cant just lose fat in one place! |
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Agressive Treatments for clinically severe obesity ( BMI over 40 or over 35 with health problems)
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two common approaches
1) drugs minidia- appetite suppressment xyidina-blocks fat absorption 2) surgery lapband- reduce the opening from esphaguaus to the stomach gastric bypass - small stomach pouch creates an outles directly to the small intestine bypassing the stomach |
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weight managment strategies
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learn alternative ways to deal with emotions and stress
attend support groups limit low fat treats to the serving size on the label |
