Chapter 18/22: Nutriton for Health and Performance Flashcards

1
Q

what is RDA (Recommended Daily Allowances)?

A

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

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2
Q

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

A

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

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3
Q

underweight BMI

A

<18.5 kg/m2

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4
Q

normal BMI

A

18.5- 24.9 kg/m2

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5
Q

overweight BMI

A

25-29.9 kg/m2

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6
Q

obesity - class I BMI

A

30-34.9 kg/m2

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7
Q

obesity class II BMI

A

35-39.9 kg/m2

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8
Q

extreme obesity - class III

A

> 40 kg/m2

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9
Q

what is the EER (Estimated Energy Requirement)?

A

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

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10
Q

examples of carbs than can be digested and metabolized for energy

A

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

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11
Q

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

A

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

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12
Q

who needs more fiber, men or women?

A

men

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13
Q

how does fuel selection change with increasing exercise intensity?

A

increased carb utilization

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14
Q

how does fuel selection change with increasing exercise duration?

A

increased fat utilization - switching to aerobic & depleted glycogen stores

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15
Q

time to exhaustion is related to..

A

initial muscle glycogen stores

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

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16
Q

3 factors affecting muscle glycogen levels

A

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

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17
Q

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

A

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

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18
Q

mechanism by which a high carb diet increases endurance performance

A

increase muscle glycogen and performance time

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19
Q

how does prior exercise affect muscle glycogen level?

A

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

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20
Q

describe the concept of muscle glycogen “supercompensation”

A

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

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21
Q

**classical **method of muscle glycogen supercompensation

A

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?)

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22
Q

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

A

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

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23
Q

modified plan of muscle glycogen supercompensation

A

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

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24
Q

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

A

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

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25
Q

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

A
  • faster rate of muscle glycogen utilization (faster decline)
  • fall in blood glucose during exercise caused by spike in insulin (not dependent on amount of CHO consumed)
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26
Q

best time to eat CHO before exercise

A
  • 2-3 hours before: allows time for digestion
  • 5-10 mins before: quick energy - minimizes risk of hypoglycemia
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27
Q

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

A

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

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28
Q

advantage of consuming carbs during exercise?

A

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

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29
Q

recommendations for carb intake during exercise

A

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

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30
Q

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

A

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

4-8 gels

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31
Q

advantage of consuming CHO after exercise

A

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

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32
Q

3 recommendations for CHO consumption after exercise

A

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!)

33
Q

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

A

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

34
Q

purposes of dietary fats

A

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

AMDR ~ 20-35

35
Q

effect of “fat loading” on endurance performance

A

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

36
Q

what do high-quality proteins contain?

A

nine essential amino acids that cannot be synthesized in the body

37
Q

protein RDA? do most Americans reach it?

A

0.8 g/kg*day

most americans meet this, may be higher for athletes

38
Q

average athlete intake for protein

A

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)

generally a similar amount needed for endurance and strength

39
Q

what percent water loss affects performance

A

3-4% water loss

40
Q

AI for water, women and men respectively

A

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

41
Q

what does water loss via sweat depend on?

A

exercise intensity and environmental conditions

42
Q

fluid replacement goals before exercise

A

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

43
Q

goal of fluid replacement during exercise

A

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

44
Q

fluid replacement during exercise is associated with lowering these three things

A

lower body temp, lower HR, and lower RPE

45
Q

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

A

500-1000 ml water

46
Q

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

A

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

47
Q

water replacement for events >3 hours

A

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

48
Q

fluid replacement goal after exercise

A

goal is to replenish water, electrolytes, and muscle glycogen

49
Q

recommended water intake after exercise (amount and type)

A

1.5 L fluid for every kg of weight loss

cold drinks more effective but carb-electrolyte beverages or skim milk equally effective

50
Q

functions of calcium

A

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

51
Q

calcium RDA

A

1000 mg/day

52
Q

dietary sources of calcium

A

leafy greens, animals products

53
Q

parathyroid hormone affect on blood calcium levels

A

increases blood calcium levels

54
Q

purpose of bones in maintaining calcium homeostasis?

A

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

55
Q

how does intense and/or prolonged exercise affect PTH?

A

increases PTH

56
Q

functions of iron

A

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

57
Q

iron RDA for men and women

A

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

58
Q

dietary sources of iron

A

meat sources, leafy greens

59
Q

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

A

VO2 max and endurance

60
Q

who is iron deficiency more common in?

A

female athletes and distance runners

61
Q

what might an iron deficiency be due to?

A

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)

62
Q

affects of iron supplementation, rapid piece and slower piece?

A

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

63
Q

functions of sodium

A

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

64
Q

AI for sodium

A

1500 mg/day

65
Q

dietary sources of sodium

A

chips, pretzels, soup

66
Q

average intake for sodium for Americans

A

3400 mg/day

67
Q

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

A

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

68
Q

best test of salt/water replacement

A

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

69
Q

characteristics of fat soluble vitamins

A

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

70
Q

characteristics of water soluble vitamins

A

B vitamins, C
involved in energy metabolism

71
Q

is supplementation with vitamins advised?

A

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

72
Q

do vitamins improve performance?

A

not really

73
Q

vitamins C & E may interfere with what?

A

muscle adaptations

74
Q

purposes of precompetition meal

A

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

75
Q

nutrients in precomp meal

A

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

76
Q

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

A
  • 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
77
Q

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

A
  • ingest CHO (30-60g/hr)
  • Hydrate with a CHO solution with 10-20 mEq Na+
78
Q

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)

A
  • 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)
79
Q

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

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