Chapter 9

body composition

another way to assess body weight ration of body fat to lean tissue excess body fat increases health risk whereas having more lean tissue does not

thyroxine

more=increases BMR lowest when we sleep made by iodine

thermic effect of food

10% of total energy TEF can vary -bigger meal= higher TEF -high fat= lower TEF why? bc fat can be used and stored more efficiently

environmental and life style and obesity

-enticements to eat (readily available food/food advertisements) -sedentary lifestyle will make you obese

ABCs of behavior modification

1. ID antecedents (what caused it) -use a food diary 2. recognize the behavior -id behaviors that cause weight gain 3. see the consequences -physiological/psychological 4. modify behavior -empowerment/plan/gradual 5. enjoy new consequence

what decreases BMR?

1. age: as you get older you lose lean body mass 2. fasting/starvation: body conserves energy and lowers BMR 3. resting position: lowest when lying down 4. under active thyroid gland: secrete less thyroxine so decreases BMR

successful long term weight loss management involves:

1. decreasing energy intakes 2. increasing physical activity 3. modifying behavior

factors that cause satiety

1. distention of the stomach due to food 2. intestinal distension and presence of nutrients in small intestine - hypothalamus is informed that meal was consumed; brain triggers satiety hormones 3. nutrient levels in circulating blood

reasons why we are eating more

1. food is more readily available 2. availability of food stimulates our appetite 3. portion sizes (have increased 2-5 larger--> we will eat this) 4. Social changes (more fast food; busier so less meals are prepared) (more single parent/double working parent households) 5. imbalance of energy (less energy at work, home, and play)

tools to aid us in keeping up with calories consumed

1. food labels (portion/ serving size) 2. nutritional database (USDA Food composition) 3. MyPlate (plans diet/guidance on types and how much food to eat) 4. Nutritional fitness apps

steps for gaining weight

1. medical evaluation for low wt. -rule out medical condition 2. gradually introduce energy dense foods 3. strength and endurance exercises

5 factors that influence hunger/appetite

1. sight, smell, taste, of food 2. contraction of an empty stomach 3. low nutrient levels in small intestine/blood 4. Ghrelin 5.physiological factors (comfort)

factors that increase BMR

1. thyroxine 2. age/growth 3. height 4. body comp 5. exercising 6. gender 7. pregnancy 8. environmental temperature 9. fever

energy required for physical activity

15-30% of total energy expenditure

DGA for americans and physical activity

150 min for moderate intense aerobic activity -some may need more -some may need to do this gradual (ppl who don't often exercise)

healthy body fat level for women

21-32%

how much percent is basal metabolism of total energy expenditure

60-75%

healthy body fat level for men

8-19%

underweight

<18.5

obese

>30 kg/m2

morbid obesity

>40 kg/m2

underwater weighing

A method of estimating total body fat by weighing the individual on a standard scale and then weighing him or her again submerged in water difference between the two weights is used to estimate total body volume.

healthy weight

BMI 18.5-24.9 weight that minimizes health risk

when is waist circumference not useful

BMI greater than 35

exercise increases

BMR

monetary costs of obesity

Higher health care costs and decreased productivity in the work place

health risks of being underweight

If an individual is predisposed to be naturally thin: no risks associated with being underweight. May have a decreased risk for developing certain chronic diseases If being underweight is self-induced or the result of a disease state: immune system will be compromised; increased health risks

psychological costs of obesity

Increased risk of depression, negative self-image, feelings of inadequacy, being discriminated against

BMI

It is a measure of body weight relative to height Correlates significantly with body fatness Helpful tool in determining something else associated with body weight health risks

is BMI on itself a diagnostic tool?

NO physical activity, blood pressure, blood glucose levels, cholesterol levels, smoker?, waist circumference, diet, family history

basal metabolism

NOT digesting food energy expended to maintain an awake, resting body Includes all the essential metabolic reactions and life- sustaining functions to keep you alive (breathing, heartbeat, circulation, nerve impulses, hormone secretions, maintaining an appropriate body temperature, removal of waste, and the making of new tissue)

what can trigger an eating disorder?

Sexual abuse; daily teasing & being bullied; judgmental comments by a friend, family member, or coach; bereavement; and having a disease or chronic condition

dual energy x ray absorptiometry

Uses x-rays to measure bone, fat, and fat-free mass

steps to follow to determine who would benefit from weight loss (step 2) (individual is overweight)

access for obesity related conditions that increase health risks --> if obese go straight to weight loss -high blood pressure, abnormal blood lipids, blood glucose, sleep apnea, inactive, cigarettes, family history

drawbacks of skin fold tests

administered by untrained technician assumption that this area of fat represents total fat

lean body mass decreases and body fat increases with ____

age

energy balance

amount of energy in vs out consume more than expend? gain weight problem in US

appetite vs hunger

appetite (external cues such as sight, smell, and taste of food stimulates endorphins) -other: hormones, food preferences, drugs, eating habits hunger (internal physiological signals) -empty stomach/low nutrients in blood -usually sets in 4-6 hours after eating

estimated energy requirements (EER)

average energy intake values predicted to maintain body weight in a healthy individual as set forth by the DRI committee is called

managing body weight

balance intake/expenditure for some its weight management= avoiding gains in weight others its obtain a weight that minimizes health risk= dietary and lifestyle changes may be necessary

assessing weight in 2-20 YOs

based on age and gender Calculate BMI & use the Body Mass Index-for-Age Gender Specific -this contains series of lines indicating percentiles -ex: 5th percentile means only 5% would have lower BMI

balancing energy intake with energy expenditure

be aware of foods/beverages consumed energy comes from types/amounts of food 4cal/g (protein/CHO) 9cal/g (fat) 7cal/g (alcohol)

overweight

being too heavy for ones height due to excess body fat 25-29.9 kg/m2

occurrences of eating disorders

can occur in all people girls are two and a half times greater typically begins in adolescence when development is occurring rapidly

obesity genes

code for proteins involved in regulation of body fat if abnormal there will be extra fat affect -how much you eat -how much energy you expend -how fat is stored in your body

how does weight gain happen

consume more energy than expend so energy is stored -Small amount of CHO is stored as glycogen in liver and skeletal muscle -Most of the excess energy-yielding nutrients are stored as TGs in fat Enlargement of fat cells and formation of new fat cells weight gain and increased body fat

steps to follow to determine who would benefit from weight loss (step 1)

determine BMI/measure circumference of waist -healthy BMI? weight loss is not necessary (maintain) -unhealthy BMI? weight loss is necessary

diet vs. fad diets

diets that are quick gain weight back right away unless you continue to consume less food

fasting/starvation and weight loss

does not work lowers BMR so fewer calories expended

what can delay satiety

eating too fast takes 20 minutes

basal metabolic rate

energy expended for basal metabolism

genetics may also have a role in keeping your body weight constant for long periods, regardless of

energy intakes and expenditures

modifying behavior (weight loss)

establishing a pattern of food intake & exercise that helps with maintaining a healthy weight identifying behaviors that led to weight gain/replace them with ones that promote weight loss/weight maintenance

genetics and obesity

even greater risk of being obese +influence of lifestyle = huge risk

increasing physical activity (weight loss)

expend 200 calories (5 days a week) + calories = wt loss of 1 lb in about 3 weeks increased energy expenditure, muscle mass, and BMR stress reliever

subcutaneous fat

fat stored directly under the skin (pear)

visceral fat

fat stored within the abdominal cavity in association with the internal abdominal organs (apple) more metabolically active higher risk of heart disease, high blood pressure, stroke, diabetes, and breast cancer

satiety

feeling of fullness and satisfaction caused by food consumption that eliminates desire to eat

EER accounts for

gender age height weight activity level (sedentary, low active, active, and very active) life stage (ex. growth)

what plays a major role in determining body weight

genes

factors that determine where fat is deposited

genes 1. positive association between visceral fat and being a man, menopausal women, Caucasian or asian, tobacco user, drinker, or stressed 2. negative relationship between visceral fat and physical activity

overall trend of obesity

getting increasingly worse now considered an epidemic (occurrence of a health related event in excess of normal expectancy)

hormones that monitor body fatness

ghrelin, peptide YY, and leptin

physiological complications with too much fat

high blood pressure, heart disease, respiratory problems, cancer

Ghrelin

hormone made by stomach that makes you hungry at your meal time regardless of the last time you ate

drawbacks of ignoring fullness

increase body weight

taller person and BMR

increased BMR

waist circumference

indicative of visceral fat BMI+waist circumference estimate health risks with excess body fat

calculation for BMI

kg/m^2

obese individuals have high levels of

leptin bc it prevents weight loss

lean body mass

mass attributed to nonfat body components such as bone, muscle, & internal organs

men or women have higher BMR

men bc more lean mass

waist circumference cutoffs

men: BMI of 25-34.9 & less than 40 in. women: BMI of 25-34.9 and less than 35 in.

how does weight loss happen

moderate reduction in calories reduction of energy caused use of stored energy: (glycogen→ glucose → ATP) (TGs (in fat cells) → fatty acids & glycerol → ATP) (proteins amino acids can make ATP and glucose)

how can you avoid obesity regardless of being predisposed or not?

monitor the diet (MyPlate and DGA) exercise regularly

other health concerns with visceral fat

more can be released into blood stream may attach to LDLs which are associated with arterial plaque/heart disease

muscle and BMR

more muscle = higher BMR

does being overweight technically mean you are unhealthy?

no if someone is overweight but eats health/exercises they are more well off

decreasing energy intakes (weight loss)

nutrient dense foods multivitamin/minerals with intakes under 1200 cal medical supervision with diets under 800 cal

energy expenditure

total amount of energy used by the body each day -3 components: basal metabolism -energy needed for physical activity -energy needed to process the food we eat (thermic effect of food)

eating disorder

physiological illness characterized by specific abnormal eating behaviors, often intended to control weight

which type of obese people are at greater risk

ppl who have been obese longer/have more body fat

medical goal for weight loss

reduce health risks losing 5-15% of body weight within 6 months should be gradual! -1/2 to 2 lbs a week (500 cal reduction a day) calories shouldn't be severely restricted

peptide YY

released in small intestine released in proportion to number of calories consumed reduce appetite

subcutaneous and blood stream

released slower, hence contributing less to blood lipid levels

yoyo diet

repeated cycle of weight loss/gain

3500 calorie reduction?

weight loss of 1 lb of body fat

leptin

secreted by adipocytes in proportion to fatness regulate energy intake and expenditure suppress the appetite and hopefully food intakes gains in body fat stimulate leptin production and decrease food consumption loss of body fat means leptin is suppressed and appetite is increased better at preventing WEIGHT LOSS

level at which body fat or body weight seems to resist change despite changes in energy intake or output is called

set point -determined by genes -regulate short term changes food intake/activity -regulate long term changes in stored body fat

what affects the amount of energy used during physical activity

size of individual strenuous of activity length of activity

anthropometric measurements

skinfold or fatfold tests and waist circumference

body weight

weight of body fat and lean body mass

air displacement

technique to assess body composition by calculating the body volume from the air replaced by an individual sitting inside a small chamber BOD POD

bioelectrical impedance

technique to assess body composition by running a weak electrical current through the body

when waist circumference is less than the cut off points..

they still have some risk associated with being overweight, but the risk is higher when the waist circumference is above the cutoff points

BMI does not equal percent body fat: T or F?

true indicator of healthfulness of body weight does not reveal body fat nor where fat is located cannot classify someone of being obese nor determine health risk

skinfold tests

used to measure thickness of fat under skin at different locations caliper does this

why do some people gain weight more readily than other?

variation of genes and how they interact (metabolism, food intakes, fat storage, activity) inherited thrifty genes (originally survival genes that preserve fat) inherited tendency to expend less energy

more likely to be obese if

your parents are obese environmental or genetic