ch10 - nutrition strategies for maximizing performance Flashcards
high vs low GI carbs precompetition?
doesn’t matter
an athlete is worried about insulin/blood sugar variation for consuming carbs. why is this misguided?
blood sugar levels typically return to normal within approximately 20 minutes, and the initial drop in blood sugar has no negative effect on performance
most important meal for aerobic endurance athletes?
precompetition meal because blood sugar levels are low and liver glycogen stores are substantially reduced
carb benefits from sports drink vs meal?
high carb meal preexercise: 9%. high-carb meal plus sports drink preexercise: 22%.
risk of not consuming carbs?
endurance athletes who are not chronically adapted to a low-carbohydrate diet and start exercise with depleted glycogen stores will break down muscle to use protein for energy and may acutely suppress immune and central nervous system functioning
downside of low glycogen stores?
may suppress immune and central nervous system functioning
benefit of prehydrating several hours before exercise?
to allow for fluid absorption and urine output. their urine specific gravity (USG) reading should be <1.02
people who may want to consider eating 4 hours before competition?
(1) athletes who get nauseated easily (2) experience diarrhea during competition (3) who get jitters (4) who compete in high intensity sports
common carb loading regimen?
three days of a high-carbohydrate diet in concert with tapering exercise the week before competition and complete rest the day before the event. “diet should provide adequate calories and carbohydrate per day: 8 to 10 g of carbohydrate per kg. this regimen should increase muscle glycogen stores 20% to 40% above normal.”
carb loading?
effective in men, but mixed in women; only high carb + surplus increases glycogen storage
athletes at risk of glycogen deficiency?
women who habitually consume less than 2,400 calories per day; may need to increase calories above this
side effects of types of carb loading?
oligosaccharides, which are found in dry beans and peas, onions, and foods with added inulin or other oligosaccharides, are rapidly fermented by bacteria in the gut, which can lead to excessive intestinal gas and bloating
optimal sport drink?
20 to 30 mEq of sodium (460-690 mg with chloride as the anion) per liter, 2 to 5 mEq of potassium (78-195 mg) per liter, and carbohydrate in a concentration of 5% to 10% but probably 6-8% (above 8% = delays gastric emptying)
fluid per hour for tennis players?
200 to 400 ml (6.8-13.5 ounces) per changeover (switching sides)
how does low glycogen stores affect training?
starting with already low carbohydrate stores will increase muscle breakdown
what are the two phases of glycogen synthesis?
(1) independent of insulin and lasts 30 to 60 minutes, and glycogen synthesis occurs rapidly (2) lasts several hours, and glycogen synthesis occurs at a much slower pace
when does glycogen synthesis occur?
when large amounts of carbohydrate, 1.0 to 1.85 g per kilogram body weight per hour, are consumed immediately after exercise or competition and at regular intervals every 15 to 60 minutes thereafter for up to 5 hours
how can athletes who eat lots of carbs attenuate muscle damage from marathons?
marathons lead to delayed glycogen resynthesis even if an athlete consumes a higher carbohydrate diet, possibly due to either metabolic disturbance or mechanical damage to muscle cells”
how does time between training affect carb intake?
athletes with >24hr to recover: can likely wait before eating after exercise and replace glycogen over 24hr period, athletes who train 2x/3x day: eat high carb meal immediately after event to replenish glycogen
can protein increase rate of glycogen storage?
yes, if carbohydrate intake is inadequate (i.e., <1.2 g of carbohydrate per kilogram body weight per hour)
carb intake to reduce muscle protein breakdown?
somewhere between 30 and 100g
main factor for muscle protein synthesis?
leucine content of protein and potentially speed of leucine delivery
when does maximal protein stimulation occur?
20 to 25 g (8.5 to 10 g of essential amino acids) of a high-quality, high-leucine, fast protein in younger people, 40g or more may be necessary in older adults
exercise interference?
concept: endurance exercise combined with strength training (back-to-back sessions) blunts gains in strength compared to strength training alone but results in improvements in endurance performance
how long does resistance training upregulate AA sensitivity vs meals upregulating anabolism?
sensitivity to amino acids for 24 to 48 hours after exercise, whereas the anabolic effect of a meal lasts approximately 3-5 hours
what regulates protein synthesis in children?
insulin and calorie intake as opposed to leucine; therefore they can consume protein in smaller amounts spread throughout their day to meet their protein needs
carb and protein intake for aerobic endurance athletes?
8g to 10g of carbohydrate / 1.0g to 1.6g of protein per kg, especially if training for >90min
nutrition for aerobic endurance when eating 4 hours and 2 hours before competition?
1 to 4 g of carbohydrate per kilogram body weight and 0.15 to 0.25 g of protein per kilogram body weight. if the precompetition meal is consumed 2 hours before exercise, athletes should aim for approximately 1 g of carbohydrate per kilogram body weight.
nutrition for aerobic endurance during exercise?
28 to 144 g of multiple types of carbohydrate (e.g. sucrose, fructose, and glucose or maltodextrin) per hour during prolonged aerobic endurance to extend time until exhaustion
nutrition for aerobic endurance when in hot weather?
sports drinks containing 20 to 30 mEq of sodium (460-690 mg with chloride as the anion) per liter, 2 to 5 mEq of potassium (78-195 mg) per liter, and carbohydrate in a concentration of 5% to 10%
nutrition for aerobic endurance postexercise?
1.5 g of carbohydrate per kilogram body weight within 30 minutes after stopping the exercise; at least 10 g of protein should also be consumed within a 3-hour time period after endurance exercise
diet for glycogen restoration?
a regular diet with sufficient carbohydrate intake can restore glycogen over the course of a 24-hour period. for faster glycogen synthesis, athletes should eat or drink a high-carbohydrate meal immediately after exercise
carb/kg for strength/speed athletes?
5 to 6 g of carbohydrate per kg; 30-100 g of carbohydrate to reduce muscle breakdown
protein recommendations for strength/speed athletes?
20g-30g per meal; 1.4g to 1.7g per kg/day; amino acid amount should be 8.5g-10g, leucine amount should be 2-3g; older adults should consume 40g protein. if exercise was performed fasted (first thing in morning or >3hr after last protein meal), protein should be consumed within 30min, if adequately fed the window may be longer
Nutrition for Hypertrophy?
(1) Between 30 and 100 g of high-glycemic carbohydrates should be consumed after muscle-damaging exercise to reduce muscle protein breakdown (2) After resistance training, younger individuals should consume at least 20 to 25 g (providing about 8.5 to 10 g of essential amino acids) of a high-quality, high-leucine protein (2-3 g), while older adults should consume 40 g or more to maximally stimulate muscle protein synthesis in the acute time period after training (3) Adult athletes should eat meals containing at least 20 to 30 g of a higher-leucine protein every 3 to 4 hours.
Nutrition Guidelines for Muscular Endurance?
(1) Maintain adequate hydration by preventing water weight losses exceeding 2% of body weight (2) During prolonged training or competition, carbohydrate-electrolyte beverage to delay fatigue and improve performance, particularly if performing after an overnight fast (3) Fully replace glycogen stores before the next training session or competition (4) Consume protein after training or games to minimize muscle damage and soreness
how to measure BMR?
after an overnight fast (12 to 14 hours without food) with the subject resting supine and motionless but awake
RMR vs BMR?
used instead of BMR due to the ease of measurement (an overnight fast is not required), yet it is 10% to 20% higher than BMR due to increased energy expenditure resulting from recent food intake or physical activity completed earlier in day
how much RMR difference does fat free mass explain?
approximately 70% to 80% of the difference in RMR among individuals
how many calories does the thermic effect of food account for?
10% to 15% of total calories burned each day
how does Harris-Benefit work for RMR?
takes sex, body weight, height, and age into account to predict RMR; resting metabolic rate can then be multiplied by an activity factor from 1.2 (sedentary) to 1.9 (heavy physical activity) to predict RMR
what is the Cunningham Equation?
a method of estimating RMR based on lean body mass. an activity factor (e.g. MET values, 1 = sitting quietly) can be used to estimate total daily energy expenditure. The Cunningham equation takes the same variables into account as Harris-Benedict but also includes fat-free mass, making it more applicable to athletes
protein for athletes to maintain muscle and lose body fat while dieting?
1.8 to 2.7 g protein per kilogram body weight per day (or approximately 2.3-3.1 g protein per kilogram fat-free mass per day) in addition to maintaining a moderate energy deficit of approximately 500 calories/day
overweight and obesity threshold?
a body mass index (BMI) of 25-29.9 and >30, respectively
what are the risk factors of overweight/obesity?
increase risk of morbidity from: (1) hypertension (2) dyslipidemia (3) coronary heart disease (4) gallbladder disease (5) stroke (6) type 2 diabetes (7) sleep apnea (8) osteoarthritis (9) respiratory problems (10) endometrial, breast, prostate, and colon cancers
what should the goal for weight loss in overweight and obese individuals be?
10% of initial weight within six months
circumference thresholds for overweight/obese risk?
men: waist circumference greater than 40 inches (102 cm), while women: greater than 35 inches (88 cm)
what should obese clients be screened for?
coexisting illnesses such as diabetes, orthopedic problems, cardiac disease, psychological disorders such as binge-eating disorder or depression, social and cultural influences, and readiness for change
what does rapid weight loss generally refer to?
faster than can be achieved by lowering calorie intake and increasing exercise in a short period of time (e.g. diuretics, >2% water loss)
potentially dangerous weight loss techniques?
fasting, fad diets, voluntary dehydration (diuretics, sauna, water and salt manipulation, wearing multiple layers of clothing), excessive spitting, self-induced vomiting, laxative abuse, and inappropriate or excessive use of thermogenic aids
side effects of rapid weight loss?
(1) dehydration, (2) heat illness, (3) muscle cramping, (4) fatigue, (5) dizziness, (6) suppressed immune system functioning, (7) hormone imbalances, (8) hyperthermia, (9) reduced muscle strength, (10) decreased plasma and blood volume, (11) low blood pressure, (12) electrolyte imbalances, (13) kidney failure (diuretic abuse), (14) fainting, and (15) death
categories of athletes prone to eating disorders?
(1) sports with weight classes such as wrestling (2) sports that emphasize leanness such as cross-country running (3) aesthetic sports such as gymnastics/bodybuilding
an athlete has disordered eating. should you refer to physician right away?
those with disordered eating do not meet the full diagnostic criteria for an eating disorder; abnormal eating patterns and amenorrhea alone are not indicative of an eating disorder
how do anorexics handle food?
ritualistic behaviors including repeated weighing, cutting food into small pieces, and carefully portioning their food
restricting vs binge-eating purging anorexia?
the restricting type does not regularly binge eat or purge, while the binge-eating or purging type regularly engages in binge eating or purging
an athlete with which eating disorder is most at risk for death?
anorexia; highest mortality rate
binge-eating episodes are associated with three or more of?
(1) Eating much more rapidly than normal (2) Eating until feeling uncomfortably full (3) Eating large amounts of food when not feeling physically hungry (4) Eating alone because of feeling embarrassed by how much one is eating (5) Feeling disgusted with oneself, depressed, or very guilty afterward
lifetime prevalence of binge-eating disorder for men and women?
2.0% and 3.5%, respectively, and average age of onset is 25 years old
bulimia purging definition?
self-induced vomiting, intense exercise, laxative use, or diuretic use. the binging and purging occur at least once a week for a period of three months
average age of onset for bulimia nervosa / prevalence?
20 years old, lifetime prevalence is 0.6%
Avoidant/restrictive food intake disorder (ARFID)?
eating or feeding disturbance, including apparent lack of interest in eating or food; avoidance based on the sensory characteristics of food; or concern about aversive consequences of eating
persistent failure to meet appropriate nutritional or energy needs associated with one (or more) of the following:
(1) Significant weight loss (or failure to achieve expected weight gain or faltering growth in children), (2) Significant nutritional deficiency, (3) Dependence on enteral feeding or oral nutritional supplements, (4) Marked interference with psychosocial functioning
physical signs of anorexia/bulimia?
there is no evidence of a disturbance in the way in which one’s body weight or shape is experienced.
when does the severity of eating disorder warrant medical attention?
when eating disorder is comorbid with another eating disorder
pica criteria?
eating nonnutritive substances for a period of at least one month. common substances include clay, laundry starch, ice, cigarette butts, hair, or chalk. may have electrolyte and metabolic disorders, intestinal obstruction, wearing away of tooth enamel, and gastrointestinal problems, among other issues. (associated with iron deficiency.)
rumination disorder criteria?
chewing, reswallowing, or spitting of regurgitated food. one must display this behavior, unrelated to any medical condition, for at least one month.
should a S&C professional give eating fix recommendations to disordered eaters?
it is not the responsibility of the strength and conditioning professional to treat or diagnose an eating disorder, just to refer to appropriate professional
