Chapter 18/22: Nutriton for Health and Performance

Question 1

what is RDA (Recommended Daily Allowances)?

Answer 1

quantity of each nutrient to meet the needs of nearly all healthy persons within a specific life stage

Question 2

what is AI (Adequate Intakes)? when is it used?

Answer 2

recommended daily intake based on apparently healthy people, used when RDA cannot be determined

Question 3

underweight BMI

Answer 3

<18.5 kg/m2

Question 4

normal BMI

Answer 4

18.5- 24.9 kg/m2

Question 5

overweight BMI

Answer 5

25-29.9 kg/m2

Question 6

obesity - class I BMI

Answer 6

30-34.9 kg/m2

Question 7

obesity class II BMI

Answer 7

35-39.9 kg/m2

Question 8

extreme obesity - class III

Answer 8

> 40 kg/m2

Question 9

what is the EER (Estimated Energy Requirement)?

Answer 9

average dietary energy intake predicted to maintain energy balance considering age, sex, weight, height, and level of physical activity

Question 10

examples of carbs than can be digested and metabolized for energy

Answer 10

sugars and starches; BG is maintained within narrow limits by endocrine system

Question 11

example of carbs than cannot be digested or metabolized. purpose?

Answer 11

dietary fiber, provides a sense of fullness during a meal and reduces transit time in intestine

Question 12

who needs more fiber, men or women?

Answer 12

men

Question 13

how does fuel selection change with increasing exercise intensity?

Answer 13

increased carb utilization

Question 14

how does fuel selection change with increasing exercise duration?

Answer 14

increased fat utilization - switching to aerobic & depleted glycogen stores

Question 15

time to exhaustion is related to..

Answer 15

initial muscle glycogen stores

the larger your storage capacity for glycogen the longer youll be able to put off exhaustion

Question 16

3 factors affecting muscle glycogen levels

Answer 16

1) carbohydrate content of diet
2) prior exercise
3) muscle glycogen “supercompensation”

Question 17

how does a high carb diet affect performance? when is it most important?

Answer 17

endurance performance if improved by a diet high in carbs, most important in events at high intensity lasting over an hour

Question 18

mechanism by which a high carb diet increases endurance performance

Answer 18

increase muscle glycogen and performance time

Question 19

how does prior exercise affect muscle glycogen level?

Answer 19

glycogen depletion leads to greater synthesis following exercise (High-CHO diet = even greater synthesis)

Question 20

describe the concept of muscle glycogen “supercompensation”

Answer 20

exhausting exercise depletes glycogen content in active muscles, then rest and high-carb diet results in glycogen overshoot in those muscles

Question 21

**classical **method of muscle glycogen supercompensation

Answer 21

1) prolonged strenuous exercise to deplete glycogen stores
2) a high-fat/protein diet for three days while containing to train
3) 90% carb diet for three days with inactivity (tapering?)

Question 22

**why is the classical method of muscle glycogen hard for athletes to maintain?

Answer 22

both diets are incredibly hard to do & asking athletes not to train before their event makes them feel unprepared
* run risk of detraining with three days of inactivity

Question 23

modified plan of muscle glycogen supercompensation

Answer 23

1) tapering workouts (90 down to 40 minutes) over several days while eating 50% CHO diet
2) two days of 20 minute workouts while eating 70% CHO diet
3) day of rest eating 70% CHO diet before event

with this plan we still see compensation within completely depleting glycogen stores

Question 24

major purpose (ie what outcome we’re shooting for) of glycogen loading prior to prolonged exercise?

Answer 24

improve performance - running out of glycogen either mean exercise must stop or preformance is impaired

Question 25

what does consuming CHO 30-45 minutes prior to exercise cause? why?

Answer 25

* faster rate of muscle glycogen utilization (faster decline) * fall in blood glucose during exercise caused by s**pike in insulin** (not dependent on amount of CHO consumed)

Question 26

best time to eat CHO before exercise

Answer 26

* 2-3 hours before: allows time for digestion * 5-10 mins before: quick energy - minimizes risk of hypoglycemia

Question 27

3 recommendations on CHO intake before exercise (type, timing, form)

Answer 27

1) avoid high glycemic index carbs (broken down too quickly) 2) consume carbs in last 5 mins or during warmup to minimize risk of hypoglycemia (no insulin spike) 3) the form of CHO (gel or liquid) does not matter

Question 28

advantage of consuming carbs **during** exercise?

Answer 28

carb ingestion can maintain plasma glucose even as glycogen is depleted, which **delays fatigue and improves performance**

Question 29

recommendations for carb intake during exercise

Answer 29

throughout exercise or prior to fatigue (30-60 g CHO/ hour) * must ingest by the 2 hr mark or its too late to recover blood glucose

Question 30

How many gels would a 30 year old female cyclist need to consume durin a 3 hour road race (1 gel = 21 g CHO)

Answer 30

30-60 g CHO/hr x 3 hrs = 90-180 90/21 = ~4 180/21 = ~8 **4-8 gels**

Question 31

advantage of consuming CHO after exercise

Answer 31

We can enhance **glycogen synthesis** after exercise by feeding during the window of increased glycogen synthase activity

Question 32

3 recommendations for CHO consumption after exercise

Answer 32

1) CHO should be consumed immediately after exercise (**1-1.5 g/kg** within 30 minutes, then at 2 hour intervals for 6 hours) 2) high glycemic index foods are better 3) addition of protein is beneficial because it reduces CHO need to resynthesize glycogen and it enhances muscle protein synthesis (repair muscles!)

Question 33

T or F: When comparing exhaustive exercise to no exercise, glycogen storage levels will deplete and only return back to baseline levels when consuming CHO during recovery

Answer 33

False: glycogen stores will return to baseline, consuming CHO will cause "supercompensation"

Question 34

purposes of dietary fats

Answer 34

fuel for energy, hormone synthesis, absorption of fat-soluble vitamins, cell membrane structure, insulation, and protection of vital organs | AMDR ~ 20-35

Question 35

effect of “fat loading” on endurance performance

Answer 35

fat loading will increase fat oxidation during exercise BUT this occurs at the expensive of a reduction in muscle glycogen stores, thus negating any beneficial effects

Question 36

what do high-quality proteins contain?

Answer 36

nine essential amino acids that cannot be synthesized in the body

Question 37

protein RDA? do most Americans reach it?

Answer 37

0.8 g/kg*day most americans meet this, may be higher for athletes

Question 38

average athlete intake for protein

Answer 38

1.5 g/kg*day requirments rlly only go higher than the RDA for all americans if doing **high-intensity exercise** or **adding muscle mass** (16% protein) * light to moderate intensity and maintaing strength only requires RDA amount (12% or 0.8) ## Footnote generally a similar amount needed for endurance and strength

Question 39

what percent water loss affects performance

Answer 39

3-4% water loss

Question 40

AI for water, women and men respectively

Answer 40

2.7 L/day for women, 3.7 L/day for men

Question 41

what does water loss via sweat depend on?

Answer 41

exercise intensity and environmental conditions

Question 42

fluid replacement goals **before** exercise

Answer 42

goal is to be euhydrated, foods and beverages consumed at meals should be sufficient if additional fluids are needed: slowly drink beverage at least 4 hours prior, sodium in beverages or salted snacks help retain fluid

Question 43

goal of fluid replacement during exercise

Answer 43

goal is to reduce risk of excessive dehydration, important for both prolonged and intermittent exercise

Question 44

fluid replacement during exercise is associated with lowering these three things

Answer 44

lower body temp, lower HR, and lower RPE

Question 45

water replacement for events <1 hour (80-130% VO2 max)

Answer 45

500-1000 ml water

Question 46

water replacement for events 1-3 hours (60-90% VO2 max)

Answer 46

800-1600 ml of 6-8% CHO solution with 10-20 mEq Na

Question 47

water replacement for events >3 hours

Answer 47

500-1000 ml of 6-8% CHO solution with 20-30 mEq Na

Question 48

fluid replacement goal after exercise

Answer 48

goal is to replenish water, electrolytes, and muscle glycogen

Question 49

recommended water intake after exercise (amount and type)

Answer 49

1.5 L fluid for every kg of weight loss cold drinks more effective but carb-electrolyte beverages or skim milk equally effective

Question 50

functions of calcium

Answer 50

provides bone and tooth strength, helps blood clotting, aids nerve impulse transmission, muscle contraction

Question 51

calcium RDA

Answer 51

1000 mg/day

Question 52

dietary sources of calcium

Answer 52

leafy greens, animals products

Question 53

parathyroid hormone affect on blood calcium levels

Answer 53

increases blood calcium levels

Question 54

purpose of bones in maintaining calcium homeostasis?

Answer 54

bones are a “store”, PTH causes bone breakdown to release calcium into blood when dietary intake is inadequate

Question 55

how does intense and/or prolonged exercise affect PTH?

Answer 55

increases PTH

Question 56

functions of iron

Answer 56

found in hemoglobin in RBCs, which is involved in oxygen transport to cells

Question 57

iron RDA for men and women

Answer 57

8 mg/day for males 18 mg/day for females

Question 58

dietary sources of iron

Answer 58

meat sources, leafy greens

Question 59

what does an iron deficiency affect that is relevant to exercise?

Answer 59

VO2 max and endurance

Question 60

who is iron deficiency more common in?

Answer 60

female athletes and distance runners

Question 61

what might an iron deficiency be due to?

Answer 61

due to decreased calcium intake and decreased absorption (diets low in red meat, dieting for weight loss or vegetarian diets) or due to increased calcium loss (via sweat, feces, and urine)

Question 62

affects of iron supplementation, rapid piece and slower piece?

Answer 62

rapid: restores hematocrit and VO2 max slower: increase in mitochondrial activity and endurance

Question 63

functions of sodium

Answer 63

major ion of extracellular fluid, directly involved in maintenance of resting membrane potential, generation of an action potential in nerves and muscles

Question 64

AI for sodium

Answer 64

1500 mg/day

Question 65

dietary sources of sodium

Answer 65

chips, pretzels, soup

Question 66

average intake for sodium for Americans

Answer 66

3400 mg/day

Question 67

what population requires more salt? why and how should they get it? how much??

Answer 67

athletes because they must replace salt lost in sweat **(****1.9 g Na+ per L sweat)** Salt needs to be met at meals NOT by consuming salt tablets

Question 68

best test of salt/water replacement

Answer 68

body weight, constant body weight indicates adequate salt and water intake

Question 69

characteristics of fat soluble vitamins

Answer 69

A, D, E, K can be stored in the body excessive intake can be toxic

Question 70

characteristics of water soluble vitamins

Answer 70

B vitamins, C involved in energy metabolism

Question 71

is supplementation with vitamins advised?

Answer 71

no, unless clear deficiency is known (some small athletes with low-energy diets may have deficiencies)

Question 72

do vitamins improve performance?

Answer 72

not really

Question 73

vitamins C & E may interfere with what?

Answer 73

muscle adaptations

Question 74

purposes of precompetition meal

Answer 74

provide adequate hydration, provide CHO to top off liver glycogen stores, avoid sensation of hunger, minimize GI tract issues, allow the stomach to be relatively empty at the start of competition

Question 75

nutrients in precomp meal

Answer 75

fluid: sufficient to maintain hydration mostly complex carbs: limit simple sugars, especially fructose low fat/fiber: to speed gastric emptying low protein: contributes to acids in blood food should be familiar liquid meal replacements can also be used

Question 76

Given an athlete’s age, height, and weight, come up with the dietary recommendations for an athlete preparing for an endurance event. Immediately after the race

Answer 76

* Consume 1-1.5 g/kg of CHO within 30 minutes * rehydrate - 1.5 L for every kg of weight loss * add protein for repair

Question 77

Given an athlete’s age, height, and weight, come up with the dietary recommendations for an athlete preparing for an endurance event. Include in your recommendation During the race

Answer 77

* ingest CHO (30-60g/hr) * Hydrate with a CHO solution with 10-20 mEq Na+

Question 78

Given an athlete’s age, height, and weight, come up with the dietary recommendations for an athlete preparing for an endurance event. Include in your recommendation Day of race (pre-comp meal)

Answer 78

* complex carbs (70% CHO diet day of) * low fat and low protein * fluid to maintain hydration * CHO should be consumed 2-3 hours before or in last 5 min before exercise (gel or liquid)

Question 79

Given an athlete’s age, height, and weight, come up with the dietary recommendations for an athlete preparing for an endurance event. Include in your recommendation Week prior to race

Answer 79

* 50% CHO diet on day 1,2,3 * Switch to 70% CHO diet say 4 and 5