Nutrition ch. 14-16
protein needs depend on level of training
.8g/kg of body weight
reasonable weight loss
10% body weight over a 6 month period. modify diet, physical activity, and behavior
optimal foods before exercise
150-300g carbs (3-4.5g carb per kg of body weight) 3-4 hours before. small meal (4-500kcal) 2-3 hrs before. simple carbs in liquid form may provide advantage-immediate source of energy. combo of carb and protein before increases glycogen content in liver and muscle. after- results in greater protein synthesis
fat needed for exercise
25-30% of kcal
genetics can influence hunger, satiety, and insulin
40 genetic variants with obesity. there are SNP's that affect eating behavior adiponectin- adipocytes secrete, improves body's response to insulin, reduces fat accumulation in liver and muscle, and enhances energy expenditure. higher in lean ppl, low in type 2 diabetics. may be explained by SNP. genetics may cause different rates of thermogenesis in brown adipose and NEAT "set point" body fights to remain at specific weight (theory)
underweight
500kcals per day = 1lb/week. make energy-dense nutritious choices
estimated energy requirement
EER- avg kcal intake estimated to maintain energy balance based on gender, age, height, body weight, and level of physical activity harris-benedict is similar but doesn't include lean body mass- not accurate for fat individuals
cardio
aerobic, uses o2. heart rate increases and more o2 blood is delivered to tissues. reduces stress, lowers risk of heart disease measured by max amount of o2 the muscles can consume during exercise, or VO2max. athlete- 50-80ml/kg/min, unfit 25-30
energy gap
after weight loss, person has lower overall energy needs b/c less body weight to maintain. gap= difference in daily kcals needed for weight maintenance before and after weight loss. ~8kcals/lb
resting metabolic rate RMR
amount of energy used by body, measured when lying calmly and 3-4 hrs of fastin. ~6% higher than BMR
conditioning affects use of glu and gly
amount of glycogen muscles can hold can be affected by training. 20-50% more w/ training
ergogenic aid
any substance used to improve athletic performance
appetite often triggers eating for unnecessary reasons
app= desire to eat. may be triggered by smell, taste, texture, or color of food, external cues, learned behavior, emotions
intensity affects use of glucose and glycogen
as intensity increases, % of energy derived from glucose and glycogen also increases
duration affects use of glu and gly
as muscle stores diminish, liver contributes glycogen. after 20 mins, muscles rely more on fat for fuel
number of fat cells
avg= 30-50 billion, each holding .4-.5 ug of fat. overweight usually much larger- .6-1.2 ug of fat
acute dehydration
becoming dehydrated over short period of time. if individual not adequately hydrated before, if hot/humid
total daily energy expenditure
bmr 50-70% TEE (adaptive thermogenesis and NEAT) 20-35% TEF 10%
physiological fuel values
body not as efficient as bomb cal. fuels not co2 or water stored as glycogen or fat. k cal values from bomb adapted to reflect body. corrected values = phys. fuel values.
body can use protein for energy
broken down to aas and carried to liver, getting converted to glucose via gluconeogenesis
brown/white adipose tissue
brown- fat cells contain mitchondria and blood. generates heat white-storage for excess kcal
bicarbonate loading may improve anaerobic metabolism during exercise
buffer lactate buildup. baking soda may be beneficial pre-workout. sides of nausea, bloat, reflux
waist circumference
can quickly reveal if increased health risk. woman- more than 35 inches man- more than 40
carb requirement depends on exercise duration
carbs are important to provide muscles w/ adequate glycogen carb loading- to build up stores before a competition best to eat during and immediately after- sports drinks, cars, bananas, bagels, corn flakes. imediately absorbed complex carbs like past are best for a couple hours before
optimal foods after exercise
carbs to replenish muscle and liver glycogen. most receptive to storing w/in 30-45 mins carbs and pro= incr muscle protein and glycogen synthesis. 4:1 ratio ideal. liquid sources common. whey protein easily absorbed. high-fat= easy fatigue
5 components of physical fitness
cardiorespiratory endurance- ability to sustain for an extended amount of time. requires heart, blood, and lungs provide enough o2 and nutrients to muscles to avoid fatigue muscular endurance- exert force over a long period of time. muscle strength and endurance = muscular fitness flexibility- range of motion around a joint body composition- proportion of muscle, fat, water, and other tissues.
body fat distribution affects health
central or android obesity- excess visceral and subcutaneous fat stored in abdomen. more freq in men gynoid obesity- excess subcutaneous fat stored in lower body thighs and butt. more freq in women visceral fat stored in liver, believed that fatty acids released travel to liver & can lead to insulin resistance, high levels of fat, low HDL, high LDL
behavior modification
changing the eating behaviors that contribute to weight gain or impede weight loss. keep food log, control environmental cues, learn how to manage stress
binge eating disorder
compulsive overeating. health effects common to obesity
bulimia
cycles of eating and purging(any behavior that assists in getting rid of food). vomiting- swollen parotid glands, tooth decay and gum disease. electrolyte imbalance, dehydration, constipation
body fat levels affect health
desirable men- 10-20% women 16-26%
intensity affects use of fat
during rest and aerobic exercise(req o2 to be converted intoenergy).
disordered eating
eating patterns considered abnormal and potentially harmful. refusal to eat, compulsive eating, binge eating, restrictive eating, vomiting, abuse of diet pills
adaptive thermogenesis
energy expended by producing heat. adaptive= body's regulation of heat production- influenced byenvironmental changes- stress, temp, diet. shivering = example
energy balance
energy in vs energy out
negative energy balance
energy ingested doesn't meet energy output. stored fat broken down.
positive energy balance
energy intake is greater than the amount of energy expanded incr in muscle mass or fat pregnancy, childhood, infancy, adolescence 3500kcal = 1 lb
basal metabolism
energy needed for vital functions, expressed as basal metabolic rate (BMR). 50-70% total daily energy determined by BMR age, gender, body size, genes, ethnicity, emotional and physical stress, thyroid levels, nutritional state, environmental temp, caffeine, nicotine affect BMR indirect measurement of o2 consumed. best results = lab motionless and after fastin
Thermic effect of food (TEF)
energy used for digestion and absorption. body uses energy to process fuels and extract kcals during catabolism. ~10% of kcals in food used for TEF. nutrients influence TEF. protein has highest thermic effect (20-30%) carbs (5-10%) fat (0-3%) composition of meal, alochol intake, age, athletic status influence TEF.
gene-environment interaction
environment has strong effect on body weight
environmental factors can increase app and decr physical activity.
environment, lack of time, dining out, abundant food supply and portion distortion, lack of physical activity
weight management
esential for physical and emotional well-being ama considers obesity a disease- 2013. metabolic and hormonal disease state. each extra lb of body weight could add up to $13/yr in added medical costs for men, and $45 for women. could encourage use of drugs
most body fat is stored in adipose tissue
essential fat- fat in marrow, heart, lungs, liver, spleen, kidneys, intestine, muscle, CNS, and stored fat found in adipose tissue women have 4x as much excess stored in subcutaneous fat under skin or visceral fat around organs adipose releases fat for fuel when body in negative energy balance
exercise health benefits
event modest amounts. reduces type2 diabetes, cancer, cardio disease. improves body composition, bone health, immune function, mental well-being, sleep, reduce stress 2008 physical activity guidelines for americans- gives info and guidance to provide health benefits for those over 6
hypertrophy
fat cells expand to store more fat
hyperplasia
fat cells fill to capacity, stimulating production of more fat cells
fat= rimary source during low to moderate intensity
fatty acids stored in muscle tissue and blood (derived from adipose). taken up by muscle and go through beta-oxidation in mitochondria to produce energy. more concentrated source of energy b/c doesnt store water
anaerobic energy production during exercise
first few secs- body relies on anaerobic energy production from ATP and creatine phosphate (quick source of phosphate) found in muscle cells to resynth ATP. if maximal exercise continues beyond 10 secs, ATP recharged during anaerobic glycolysis. body produces small amount of creatine from foods. w/ help from liver and kidneys , converted to creatine phosphate
satiety
food in stomach= lining suppresses hunger. reach small intestine-> CCK and PYY releases, sending feedback to hypothalamus to decr hunger. nutrients are absorbed, and insulin is release. leptin (in adipose) increases satiety. acts of receptors in hypothalamus. creates negative energy balance by incr. body temp, increases energy expenditure and stims oxidation of fatty acids in liver and muscles protein intake from 15-30% significantly reduces food intake
optimal foods during exercise
for exercise >1 hr, food intake should begin shortly after start. endurance activities- 30-60g carbs/hr. ultra endurance 90gcarb/hr glucose, sucrose, maltodextrin best form to consume during b/c body absorbs faster carb+protein= improve net proptein balance at rest. benefits muscle maintenance and growth
duration affects use of fat
free fatty acids in blood taken up by muscles, stimulating lypolysis by way of epinephrine
fitt principle
frequency, intensity, time, type. measure intensity- rating of perceived exertion= self assess. 5-7 on RPE scale rec for adults. target heart rate- 60% low intensity, 80% high 2 1/2 of moderate exercise/week provides substantial benefits aerobic activity in sessions as short as 10 mins- some benefits
hunger
ghrelin (gastric cells on stomach) stims later hypothal. activates neruopeptide Y to stim hunger ghrelin produced between meals, during sleep, fasting lean individuals have higher levels, especially in the morning. leptin may play role in hunger b/c levels drop when adipocytes shrink. zinc lowers leptin. A & C inhibit leptin secretion
physical fitness
good health or physical condition as the result of exercise and proper nutrition
progressive overload principle
gradual increase in exercise demands resulting from modifications to the frequency, intensity, time, or type of activity muscles increase in size (hypertrophy), endurance, strength, and cardio endurance improve
anorexia
health effects- electrolyte imbalance= low K, irregular heart rhythm, unable to maintain body temp. body processes slow or shut down to conserve energy for vital functions
physical activity or exercise burns energy
heat produced by contracting muscle. referred to as thermic effect of exercise. amount of kcal needed for TEE depends on the activity, time, and weight. TEE for sedentary ppl is <50% BMR TEE for very active can be more than 2x BMR Non-exercise activity thermogenesis (NEAT) - energy expended for all other activities- fidgeting, other non-exercise activities
estimating healthy body weight
height-weight tables. provide recommended weight range for height based on gender and frame size BMI- calculate body weight in relationship to height. 18.5-24.9= healthy 25-29.9=overweight 30=obese. obese have 50-100% higher risk of dying prematurely using a combo of both gives more accurate results
hunger and satiation affect the desire to eat and stop eating
hunger- physical sensation associated with the need or intense desire for food. low blood sugar or empty stomach trigger hunger satiation- feeling of fullness both controlled by hypothalamus- ventromedial nucleus and lateral hypothalamus
body composition measured
hydrostsatic weighing, air displacement, use body volume to measure % body fat DEXA- most accurate bioelectrical impedance- low-energy current. travels faster through lean mass skinfold measuring
creatine
improves performance in high-intensity, short-duration exercise when body relies on anaerobic energy metabolism and increased muscle strength and mass. side effect-water retention
chronic dehydration
inadequately hydrated over an extended period of time. fatigue, muscle soreness, poor recovery, headaches, nausea
conditioning aaffects use of fat
incr. fatty acids stored in muscle. muscle cells produce larger mitochondria. incr enzymes that aid in fatty acid production
strength training
increase muscle mass, strength, endurance. rest between sets and workouts depend on level of conditioning. incr strength rest 2-3mins, endurance= 30 secs
deficiencies of some minerals- iron
iron- energy metabolism and transporting oxygen. structural component of hemoglobin and myoglobin. deficiency= early fatigue sports anemia- during exercise, blood volume increases, and [hemoglobin] decreases foot strike hemolysis- feet repeatedly hit hard surface, causing rbc's to burst and release iron
some vitamins and minerals contribute to energy metabolism
key to catalyzing energy held in bonds of macro. B complex activates enzymes that transform carbs, proteins, and fats to ATP folate and b12- maintain healthy RBCs phosphorous- part of ATP iron-hemoglobin iodide- necessary to produce thyroid hormone that controls metabolic rate and rate which body produces energy
timing of foods and exercise
larger meals ~ 3-4 hrs to digest, smaller 2-3. early morning competition- high carb low fat dinner will replenish glycogen stores. afternoon- morning meal is critical evening- lunch should be high carb endurance athletes- ingest carbs during supports blood glucose levels and delays depletion of glycogen
amino acid supplement
leucine, isoleucine, valine may improve muscle recovery and support immune system. beta alanine- buffer H ions, improve endurance, lean body mass carnitine- decr free radical formation, reduces muscle damage, help w/ recovery leucine- protein synthesis and muscle recovery glutamine- immune system, glucose utilization, muscle glycogen synthesis
weight loss and exercise
longer the session, higher sustained metabolic rate and more kcals burned throughout day. cardio + strength 10,000 steps/day
caffeine
may decrease perception of effort by stimulating CNS, directly affect breakdown of muscle glycogen, and incr availability of fatty acids during exercise. benefits during endurance
direct calorimetry
measures amount of body heat generated, determined using metabolic chamber.
bomb calorimeter
measures amount of heat produced when a given food is burned. energy from bonds released when broken. 1kcal = heat required to raise the temp of one kg of water 1 degree Celsius burning of food releases c and h to form co2 and water, so measuring o2 during combustion in calorimeter = indirect measure of energy content
indirect calorimetry
more practical approach to estimate amount of energy expended. indirect measurements sample amount of o2 consumes and co2 produced to exercise for a specific amount of time
lean body mass LBM
muscle, bone, and other nonfat tissue that makes up body weight. most affect BMR. burns kcals higher rate
nutrigenomics and epigenetics
n- how genetic makeup interacts with diet. has identified specific genes involved in body's response to certain nutrients e- changes in gene activity that occur without changing the gene itself. dna and histones covered w/ chemical tags that react to signals within the body. dna unwinds and can turn gene expression on/off. some vitamis donate methyl groups during metabolic reactions
orthorexia, night eating syndrome, pica
o- obsession with healthy or righteous eating. can lead to anorexia n- combo of disordered eating, sleep disorder, mood disorder. majority of kcals after evening meal p- desire to eat/lick/chew nonnutritive substances
health risk associated with
obesity correlated to heart disease, type 2 diabetes, cancer. gallstones, sleep apnea, reproductive problems underweight- BMI less than 18.5. risk of anemia, osteoporosis, bone fractures, heart irregularities, amenorrhea. low body protein/fat stores, depressed immune system. depression, anxiety
fluids needed before, during, after exercise
prior- essential to performance. women need about 9c/day, men 13. or divide body weight by 2 to get oz of water (not including additional needed w/ exercise) after exercise, you should consume 20-24oz of fluid for every lb of body weight lost
body composition
ratio of fat tissue to lean body mass
bariatric surgery
reduces food intake gastric bypass- reduce size of stomach by creating pouch that connects to jejunum. holds <1/4c. of food and reduces intestines ability to absorb. lower levels of ghrelin. 5-15lb/week for 2-3months. 1-2lbs/week after 6 months. decr risk of diabetes, hyperlipidemia, hypertension. sides- low b12, iron, calcium. glasstones, ulcers, bleeding. gastric banding- reversible. band placed around top of stomach w/ narrow opening for food to pass through. delays emptying of stomach contents so person feels fuller longer
deficiency of calcium during exercise
reduces risk of bone injuries. affects skeletal and heart muscle contraction, and hormone and neurotransmitter activity during exercise calcium lost in sweat. exercise can increase bone mineral density, which compensates
size of ft cells
regulated by lipoprotein lipase. increases lipogenesis. hormone-sensitive lipase stims hydrolysis of triglycerides heavier ppl have much more lpl activity. differences between gender
physical activity pyramid
show acivities and how often they should be performed for optimal health and physical fitness
fluid and electrolyte balance and body temp are affected by exercise
sodium, chloride, potassium lost in sweat electrolyte imbalance can cause heat cramps, nausea, low bp, and edema. easily replaced by food w/in 24 hours of exercise hyperthermia- sweat doesn't evapoate, incr risk of heat exhaustion/stroke hyopthermia- someone running slow in cold weather may produce very little heat
extreme obesity
some meds- suppress hunger or inhibit absorption of fat in intestinal tract sibutramine(meridia)- decr. hunger and incr thermogenesis. sides- incr heart rate and bp orlistat(xenical)- inhibits fat absorption. sides- taken with every meal, stool can be oily orlistat(alli)- reduced of above. combo w/ low kcal, low fat & exercise, aids in modest weight loss. lorcaserin- stims seratonin(satiety). approved based on BLOOM study. sides- stsomach problems, respiratory infection, UTI, back pain, headache, mem loss, depression
some beverages are better than other
sports drink usually contain 6-8% carbs, and na, k exercise <60 mins can be replaced by water fruit and veggie juices can add simple carbs & fluid after exercise
being overweight or under carries social and psych risks
suffer more discrimination, stereotype can lower self-esteem. higher rates of suicide, more likely to abuse alcohol and drugs underweight greater risk for irritability, anger, depression
carb= primary energy source during high-intensity exercise
through blood glucose, stored glycogen, or consumption. glycogen in muscles~ 200-500g. liver stores 60-120g. avg body stored 2600kcal, 2000 can be used blood glucose is energy for brain rate at which muscles consume lactate for energy depends on metabolic rate, ph muscle, blood flow, and fitness level
antioxidants can help protect cells from damage cause by exercise
vitamin E & C, selenium- protect cells from free radicals C helps produce collagen
eating disorders
when a person meets specific criteria that include disordered eating behaviors as well as other factors. 20mill women and 10mil men
protein used to build and repair muscle
when protein synthesis occurs more often than breakdown, conditions favor incr in muscle protein, can translate to more muscle mass, strength, and endurance exercise affects protein turnover by incr levels of cortisol
aerobic energy production during exercise
with oxygen in the cell, pyruvate formed from glucose during glycolysis is converted to acetyl coA and is metabolized through aerobic metabolism o produce ATP body relies on carbs, fat and protein. carb contributes to anaerobic and aerobic, fat to aerobic
