Human Nutrition - Exam 3
lbs to kg
divide by 2.2
aggressive treatments of obesity
drugs low calorie diet surgical treatment
factors affecting fat utilization
duration of activity (beginning activity uses fatty acids, after 20 minutes uses body fat) intensity of activity (as intensity increases, we use less fat; need oxygen to break down fat) training (the better trained muscles use more fat)
when is prevention of excess weight gain most effective?
during the growing years of childhood and adolescence
protein synthesis during and after activity
during: protein synthesis is suppressed - muscles use amino acids for fuel after: protein synthesis accelerates
what are the three main categories of thermogenesis
energy expended for: basal metabolism physical activity food digestion and absorption (thermic effect of food)
ATP
(adenosine triphosphate) main energy source that cells use for most of their work - delivers instant energy - present in small amounts in all tissues - required for muscle contraction
thermic effect of food
estimate of the energy required to process the food you eat - digestion, absorption, utilization of food and heat produce - affected by food comp and frequency of eating
what is excess energy stored as?
fat
ectopic fat
fat that accumulates outside of adipose tissue contributes to the many diseases associated with obesity
during rest, the body derives more than half of its ATP from the oxidation of ____________
fatty acids
what affects energy requirements
gender growth age physical activity body comp body size
glucose is stored in the liver and muscles as what
glycogen
drugs for weight loss
have to be taken with lifestyle changes diuretics amphetamines sibutramine phenylpropanolamine benzocaine laxatives orlistat
what kind of diets help people work out for long periods of time
high carb
factors affecting glycogen storage and use
how much carbohydrates a person eats - high carb diets enhance endurance by ensuring ample glycogen stores how long glycogen stores last depend on intensity and duration of activity - hard intensity uses the lactic acid system to break down glucose to pyruvate anaerobically conditioned muscles rely less on glucose and more on fat
when protein synthesis is greater than degradation, a person can gain muscle in a condition called __________
hypertrophy
hydration before/during/after exercise
important before drink water during drink some but not a lot after drink to replace
when we eat more we ________ fat cell numbers, and when we lose weight, the fat cells ________.
increase shrink
activity
intensity of exercise and body size - physical activity helps keep lean tissue
When do fat cells increase most rapidly?
late childhood and early puberty
the aerobic system
low intensity or long activities - carbohydrates, fats, and some amino acids are continuously oxidized to ensure an uninterrupted supply of ATP
android
mainly men body fat is accumulated in the upper body more risk
gynoid
mainly women body fat accumulated in lower body harder to lose
fast way to calculate basal metabolism
males : 1.2 kcals/kg/hr females : 0.9 kcals/kg/hr (0.9 or 1.2) x weight in kg x 24 hrs
ideal body weight
men: 106 lbs for 5 ft plus 6 lbs for every 1 inch over women: 100 lbs for 5 ft plus 5 lbs for every 1 inch over + 10% for large frame size - 10% for small frame size
what kind of fat is most/least harmful
most harmful: intra-abdominal fat (central or upper body) least: lower body fat (around hips and thighs)
what is the primary source of glucose
muscle glycogen
treatments for obesity - reasonable treatments
new philosophy: small moderate changes promote better health modest loss will lower cholesterol and blood pressure goal: 5-10% weight loss over 6 months is reasonable
why is it hard to maintain low body weight
number of fat cells doesn't decrease when weight is lost
where is the other spots where the body stores fat?
organs (heart, liver)
the body adapts to physical activity, responding to physical activity ___________ by building structures to support the activity
overload
uncoupling proteins
prevent energy from being converted to ATP, instead oxidation gives off heat - so affects basal metabolism - present in the mitochondria - white fat and other tissues have these - increases metabolic rate and energy expenditure - abundant in brown adipose, bc high number of mitochondria
as fat cells enlarge, it stimulates cell __________, meaning the number of cells increases
proliferation
LDL (lipoprotein lipase)
promotes fat storage in fat and muscle cells found on the surface of cells lining muscles and adipose tissue LPL breaks down VLDL's triglycerides, providing fatty acids for the msucles to use for energy and the adipose tissue to use for later obese = more LPL activity fat breakdown differs around the body after weight loss, LPL activity rises
what has the highest thermic effect?
protein protein > alcohol > carbohydrates > fat
determining frame size
r = height (cm)/wrist circumference (cm)
treatment for obesity - eating plan
reasonable energy intake (too little will cause loss of lean body mass) restrict intake to 10 kcals/pound make sure you are getting all the nutrients eat CHO, restrict fat, adequate water eat slow
gastric bypass surgery for weight loss
reduces stomach size so you can't eat as much might need supplements for vitamin or mineral deficiencies suppresses hunger alters metabolism by changing hormone secretion
if energy balance becomes negative, the number of fat cells ___________
remains the same
basal metabolism
represents the energy needed for vital body processes - depends mainly on lean tissues
meals before competition
should be carb rich avoid fiber and fat
myokines
signaling proteins secreted by working skeletal muscles that contribute to widespread beneficial effects of physical activity on body system - evoke changes in skeletal muscle and adipose tissue and organs
the number and ________ of fat cells increase when energy balance is positive
size
what factors affect eating disorders
societal family (unhealthy communication, emphasis on weight and perfection, high incidence of depression) individual (biological, personality, significant life events)
what happens to adipose cells when we lose weight
the adipose cells shrink, but the number of fat cells doesn't decrease
what happens when the diet delivers too little energy, carb, or protein?
the body uses its glycogen and fat stores to meet glucose and energy needs (also degrades lean tissue to meet protein (and glucose) needs)
lactic acid system (glycolysis)
the breakdown of glucose to pyruvate without the use of oxygen pyruvate is then converted into lactic acid can generate small amounts of ATP quickly for high intensity activity lasting up to 3 minutes
set point
the point at which controls are set (for example, on a thermostat). The set-point theory that relates to body weight proposes that the body tends to maintain a certain weight by means of its own internal controls.
body composition
the proportions of muscle, bone, fat, and other tissues that make up a person's total body weight
weight loss strategies
- small changes - moderate losses - reasonable goals - reasonable rate of weight loss
bulimia nervosa (health problems)
- subclinical malnutrition - tooth erosin - red eyes - calloused hands - clinical depression - high substance abuse rates
treatment for obesity - physical activity
to increase energy expenditure (short and long term) provides appetite control psychological benefits spot reducing (only for the abdomen) low to moderate long duration
what do fat cells store?
triglycerides
what happens when we do not have enough energy? what do we turn to for energy?
we break down what we stored - lose lean tissue and water and body fat
how to calculate BMI
weight (kg) / height (m^2) weight (lbs) / height (in^2) x 703 healthy : 18.5 - 24.9
energy balance
when energy in versus the energy out - a shift in balance causes weight changes
when do fat cells divide
when it reaches maximum size
brite adipocytes
white fat cells with brown fat cell characteristics when fat cells undergo browning (gain uncoupling proteins) - more abundant than brown fat cells in adults - can be triggered by exercise
overload
working the body harder than it is normally worked a principle of training that states for a body system to improve, it must be worked at frequencies that increase by increments
anorexia nervosa
An eating disorder characterized by an obstinate and willful refusal to eat, a distorted body image, and an intense fear of being fat - malnutrition - distorted body image - denial
density
D = weight/volume
muscle dysmorphia
a disorder characterized by an extreme concern with becoming more muscular
Adiponectin
a protein produced by adipose cells that inhibits inflammation and protects against insulin resistance, type 2 diabetes, and cardiovascular disease - inversely correlated with body fat (high body fat = less adiponectin) - secreted by body fat
leptin
a protein produced by fat cells (adipose) under direction of the ob gene, which suppresses appetite and stimulates energy expenditure - promotes negative energy balance and a decrease in body weight and fatness - acts on the hypothalamus - levels increase when body fat increases, and decreases when body fat decreases - levels decrease with food intake and increase with fasting, hunger, starvation
ghrelin
a protein produced by the stomach cells that enhances appetite and decreases energy expenditure - triggers the desire to eat; blood levels of ghrelin increase before a meal and decrease after - acts on the hypothalamus - lean people have high levels, obese people have low levels - a lack of sleep raises ghrelin levels - levels increase with increased body fat
weight cycling
a repeated pattern of losing and regaining body weight
hyponatremia hypernatremia
abnormally low/high concentrations of Na+ in the blood
adaptive thermogenesis
additional energy spent to adapt to a dramatic change - when exposed to extreme cold or heat
fat is stored in the ________ tissues
adipose
where is the first spot that the body stores fat?
adipose tissue: the body's natural storage site
what factors affect the BMR
age growth body comp fever : raises BMR stresses : environmental temperature fasting/starvation : losing lean tissue to be broken down for energy malnutrition smoking : stopping smoking raises weight caffiene sleep
obesogenic environment
all the factors surrounding a person that promote weight gain, such as increased food intake, especially of unhealthy choices, and decreased physical activity - pushes our population towards obesity
bulimia nervosa
an eating disorder characterized by episodes of overeating, usually of high-calorie foods, followed by vomiting, laxative use, fasting, or excessive exercise - more prevalent than anorexia nervosa - not as physically apparent - secretive nature - binge-purge cycle
binge eating disorder
an eating disorder in which people overeat compulsively - typically with no purging
____________ occurs when protein degradation is greater than synthesis
atrophy
estimated energy requirements
average energy intakes predicted to maintain body weight in healthy individuals also called daily energy expenditure
Choose the incorrect answer: a. Vitamin and mineral deficiencies impede performance b. Taking a vitamin or mineral supplement before a competition will improve performance, especially if the athlete has a vitamin or mineral deficiency c. Athletes consuming little food, for example, to "make weight" may benefit from a multivitamin-mineral supplement d. Supplements won't improve the performance of well-nourished athletes
b
factors that affect utilization of carbohydrates
diet (high carb diets allow endurance athletes to perform the longest) intensity (as intensity increases, glycogen is used quickly) lactic acid (cori cycle) duration of activity (first 20 minutes uses glycogen, after glycogen and fat is used) glucose after activity enlarges glycogen stores
PYY
digestive hormone that suppresses appetite - peptide from the stomach - signals satiety - released from the small intestine
characteristics of FAD diets
- limited food choices - excludes certain food groups - lacks certain nutrients - promises rapid weight loss - difficult to maintain
anorexia nervosa (health problems)
- "skin and bones" apperance - lower body temp - lanugo and loss of hair - lower basal metabolism - lower heart rate - iron deficiency, anemia, nutrient deficiencies - rough, dry, scaly, cold skin - low white blood cell count - constipation, amenorrhea - changes in neurotransmitter - mortality (heart failure) - osteoporosis
what are the three treatments for obesity
- lifestyle changes - medication - surgery
eating patterns to help lose weight
- be realistic about energy intake - emphasize nutritional adequacy - eat small portions - slow down - lower energy density of food - remember water - focus on plant based foods - choose fats sensibly
problems with a low carbohydrate diet
- constipation - nausea - fatigue - stale foul taste in mouth - loss of appetite - low blood pressure - elevated uric acid - dramatic weight loss (due to water loss)
bulimia nervosa (treatment)
- discontinuing purging and restrictive diet habits - learn to eat 3 meals a day plus snacks - treatments
anorexia nervosa (warning signs)
- focus on dieting - abnormal eating habits - eating very little food - preoccupation with food - hiding and storing food - prepares large meals for others - withdrawn from friends and family - critical of self and others - sleep disturbances and depression - may exercise compulsively
anorexia nervosa (treatments)
- intervention - nutrition therapy - psychological therapy
binge eating disorder (treatments)
- learn to eat in response to hunger - learn to eat in moderation - avoid restrictive diets - address hidden emotions - overeater anonymous - antidepressants
protein needs
0.8 g/kg body weight - more for physical activity
1 in = ? cm
2.54 cm
1 pound of fat
3500 kcalories
1 m = ? inch
39.37
A waist circumference of > ___ for men, and > ___ for women is an indicator of fat distribution and central obesity
40 35
components of energy expenditure
50-65% basal metabolism 30-50% physical activities 10% thermic effect of food
very low-calorie diet for weight loss
800 kcals : 1g protein/kg; 50g carbohydrate little to no fat, must take vitamin/mineral supplements slower fat oxidation and BMR
female athlete triad
A condition consisting of three interrelated disorders: abnormal eating patterns (and excessive exercising) followed by lack of menstrual periods (amenorrhea) and decreased bone density (premature osteoporosis)
creatine phosphate system
The energy pathway that consists of adenosine triphosphate (ATP) and phosphocreatine (PC) provides immediate energy (between 10 and 15 seconds) through the breakdown of these stored high-energy phosphates - for short and high intensity activities - is regenerated at rest
how to measure the energy released in food
bomb calorimeter - how we came up with how many kcals for protein, fat, carbs, and alcohol - food in burned, the change in temperature in water is measured to show how much energy is contained
health risks associated with body weight and body fat
cardiovascular disease diabetes (type II) cancer inflammation and metabolic syndrome