Athlete: body comp & nutrition issues

Question 1

What are the five main areas covered in athlete nutrition according to these lectures?

Answer 1

The five main areas covered in these athlete nutrition lectures are:
1. Total energy intake
2. Macronutrient intake (a. CHO, b. Fats, c. Proteins)
3. Micronutrient intake
4. Water intake
5. Recommendations for weight loss/gain.

Question 2

What are some scenarios where athlete nutrition needs might be particularly important?

Answer 2

Athlete nutrition needs are important in scenarios such as: an athlete moving up to a longer race (e.g., from a 10k to a ½ marathon), a master’s triathlete (Olympic distance) performing, and a soccer team playing multiple games in a short period (e.g., 4 games in 2 days).

Question 3

What should be considered when determining an athlete’s total energy intake?

Answer 3

When determining an athlete’s total energy intake, you should consider recommendations relative to body size and energy expenditure. Energy needs can be quite variable, with exceptionally high expenditures in some sports like the Tour de France. This can present challenges for both weight gain and weight loss

Question 4

How do macronutrient intake recommendations for athletes compare to those for the general Canadian population? What is an important distinction to remember?

Answer 4

In general, macronutrient intake recommendations for athletes are similar to recommendations for all Canadians. However, it is important to consider relative versus absolute intake, especially given athletes’ higher energy expenditures

Question 5

What is the acute effect of high-intensity endurance exercise on liver glycogen?

Answer 5

High intensity exercise (around 75% VO2max for 1 hour) depletes liver glycogen by 50%. Supramaximal, repetitive work also depletes glycogen

Question 6

What is the relationship between resting glycogen stores and time to exhaustion?

Answer 6

The time to exhaustion is directly related to resting glycogen stores

Question 7

What are some effects of endurance training on carbohydrate metabolism?

Answer 7

Endurance training leads to: glycogen-sparing, improved mitochondrial metabolism enhancing lipid oxidation, and larger glycogen stores in skeletal muscle, which allows for more glycogen and a longer time to exhaustion by relying on lipids and sparing glycogen.

Question 8

What is the approximate carbohydrate (CHO) content per kg of wet weight muscle? If someone has 25 kg of muscle, what is their approximate CHO storage capacity in muscle?

Answer 8

There are about 12-16 g of CHO per kg of muscle (wet weight). For someone with 25 kg of muscle, this equates to approximately 300-400 g of CHO stored in muscle.

Question 9

How does liver glycogen storage compare to muscle glycogen storage in terms of concentration and total amount? How can liver glycogen be depleted?

Answer 9

Liver glycogen has a higher concentration than muscle glycogen but a lower total amount (around 100g). Liver glycogen can be depleted to below 20g after an overnight fast, as the body uses liver glycogen while fasted.

Question 10

Besides muscle contraction, what is another critical role of glucose in the body?

Answer 10

Glucose is not just for muscle contractions; it is also critical for brain function, especially for cognitive sports.

Question 11

What are the five main categories of carbohydrate (CHO) intake guidelines for athletes?

Answer 11

The five main categories of CHO intake guidelines are:
1. General CHO intake guidelines
2. CHO intake days before competition
3. CHO intake hours before competition
4. CHO intake during competition
5. CHO intake after competition.

Question 12

Define Glycemic Index (GI). What is the reference value?

Answer 12

Glycemic Index (GI) is a measure where pure glucose is the standard reference (100). The GI is calculated as: GI = (AUC 50g other CHO / AUC 50g glucose) × 100

Question 13

What four factors can influence the Glycemic Index (GI) of a food?

Answer 13

The GI of a food can be influenced by:
1. the biochemical structure of the carbohydrate
2. the absorption process
3. the size of the food particle
4. the co-ingestion of fat, fiber, or protein

Question 14

Define Glycemic Load (GL). How is it calculated?

Answer 14

Glycemic Load (GL) takes into account both the GI of a food and the amount of carbohydrate it contains. It is calculated as: GL = (GI × g CHO) / 100

Question 15

Provide examples of foods with low, medium, and high Glycemic Index (GI).

Answer 15

• Low GI (<55): most fruit and vegetables (except potatoes), whole grains, basmati rice, pasta
• Medium GI (56 - 70): sucrose, croissant, some brown rices
• High GI (>70): corn flakes, baked potato, some white rices (e.g., jasmine), white bread

Question 16

What are the general daily carbohydrate intake guidelines recommended by ACSM for athletes?

Answer 16

The ACSM recommends a daily carbohydrate intake of 6-10 g/kg of body weight for athletes. However, the actual need depends on the training.

Question 17

What are the more specific daily carbohydrate intake recommendations based on training intensity and duration?

Answer 17

• Daily (mod duration, low intensity): 5-7 g/kg
• Daily (mod to heavy endurance): 7-12 g/kg
• Daily (extreme, 4-6 hrs): 10-12g+/kg

Question 18

What is the goal of carbohydrate loading (supercompensation) before competition? What are the potential performance benefits?

Answer 18

The goal of carbohydrate loading is to replenish and maximize muscle glycogen stores. This can lead to an increased time to fatigue by 20% and a decreased time to complete a task by 2-3%. It is most beneficial for activities lasting longer than 60-90 minutes

Question 19

What are some potential issues with classical carbohydrate loading strategies?

Answer 19

Potential issues with classical carbohydrate loading include: hypoglycemia when CHO intake is low, it may not be practical (meal prep), gastrointestinal (GI) problems, mood disturbances, and feelings of tenseness without training

Question 20

How might carbohydrate loading differ between men and women?

Answer 20

Women tend to have a greater reliance on fat oxidation, which might explain why glycogen stores could differ between genders after carbohydrate loading. Carbohydrate loading may also increase weight, potentially causing issues with compliance, although the authors suggest otherwise.

Question 21

When carbohydrate loading, which glycogen stores (muscle or liver) are often prioritized? How might fructose intake affect glycogen replenishment?

Answer 21

Muscle glycogen is often super-compensated before full recovery of liver glycogen, as muscle takes precedence. Fructose (from fruits/honey) can lead to slower muscle glycogen replenishment but similar liver glycogen replenishment compared to glucose (from pasta).

Question 22

What is the main goal of carbohydrate intake in the hours before competition?

Answer 22

The goal of carbohydrate intake 0-4 hours before exercise is to replenish/maximize liver glycogen and increase glucose delivery to muscle.

Question 23

What are the general recommendations for carbohydrate intake 3-4 hours and 30-60 minutes before exercise? What are some considerations?

Answer 23

• 3-4 hours before exercise: A meal can help increase muscle glycogen. Consuming around 200-300g of CHO is suggested.
• 1 hour before exercise: Liver glycogen can be increased (but likely not muscle). A 1.0-1.2 g/kg snack 30-60 min before exercise is now more accepted, though it was previously controversial. Concerns exist over “reactive hypoglycemia” due to excessive insulin release, which may be less common if consumed closer to exercise (e.g., 15 min) or with a warm-up. Low GI foods may help avoid excessive insulin release. Fructose may not be as effective due to slower absorption.

Question 24

How does consuming a low Glycemic Index (GI) meal 3 hours before endurance exercise at 70% VO2max to exhaustion compare to a high GI meal in terms of time to exhaustion? What is a possible reason for this?

Answer 24

Studies (e.g., Wu, 2006) have shown that consuming a low GI meal (2g/kg body mass, GI 37) 3 hours before endurance running at 70% VO2max until exhaustion resulted in a significantly longer time to exhaustion compared to a high GI meal (GI 77). This is possibly due to increased fat oxidation during exercise after the low GI meal and lower free fatty acid (FFA) levels and lower fat oxidation during exercise after the high GI meal.

Question 25

What is a crucial recommendation regarding carbohydrate intake before competition?

Answer 25

Carbohydrate intake before competition needs to be tailored to the needs of the athlete and the specific competition, and athletes should always test out their pre-competition nutrition strategies in advance of the actual competition

Question 26

What are the general recommendations for carbohydrate intake during high-intensity, long-duration exercise? What are the benefits?

Answer 26

Consuming approximately 30-60 g/hr (liquid or solid) or about 0.7g/kg/hr of carbohydrate during high-intensity, long-duration work benefits performance by extending the time to exhaustion. It is better to provide carbohydrates every 15-20 minutes rather than waiting for 2 hours.

Question 27

What type of carbohydrate is generally not recommended for intake during exercise? Why?

Answer 27

High fructose intake is generally not recommended during exercise because it is slower to absorb and can lead to more gastrointestinal (GI) symptoms. However, adding some fructose can help.

Question 28

How does exercise affect insulin release in response to carbohydrate intake during competition?

Answer 28

Exercise-induced elevation in epinephrine depresses the release of insulin.

Question 29

What are some examples of carbohydrate sources that can provide approximately 70g/hr during competition?

Answer 29

Examples include: 1 L sports drink, 600 ml cola drink, 2-3 CHO gels, 1 1/2 Power bars, three medium bananas, or 120 to 150 g wine gums. The ACSM 2009 recommends 0.7g/kg/hr

Question 30

What is the primary goal of carbohydrate intake after exercise?

Answer 30

The primary goal of carbohydrate intake after exercise is to replenish muscle and liver glycogen stores and create a positive glycogen repletion environment.

Question 31

What are the ACSM 2009 recommendations for carbohydrate intake after moderate to high-intensity exercise?

Answer 31

The ACSM 2009 recommends consuming approximately 1.0-1.5g/kg of moderate to high GI CHO within 30 minutes and every 2 hours for up to 6 hours, aiming for a total of around 500 g (7-10 g/kg body wt). This is highly dependent on the activity performed and the next activity.

Question 32

What factors affect the rate of glycogen synthesis after exercise?

Answer 32

The rate of glycogen synthesis is affected by: availability of glucose, insulin levels, and prior exercise (which increases insulin sensitivity).

Question 33

Describe the rapid and slow phases of glycogen synthesis after exercise. When is the greatest rate of glycogen synthesis observed?

Answer 33

* Rapid phase (1-2 hours): Driven by glycogen synthase (upregulated by exercise) and glucose availability. * Slow phase: Driven by insulin availability. The greatest rate of glycogen synthesis occurs immediately after exercise. Waiting 2 hours leads to a much slower rate.

Question 34

What factors contribute to the variability in glycogen synthesis after exercise?

Answer 34

Variability in glycogen synthesis is influenced by: timing of carbohydrate ingestion, type of carbohydrate ingested (HGI/LGI), type of training, and the level of glycogen stores after exercise

Question 35

According to the Parkin et al. (1997) study, what is the key takeaway regarding muscle glycogen recovery after 24 hours, assuming sufficient carbohydrate intake?

Answer 35

The Parkin et al. (1997) study showed no significant difference in muscle glycogen stores between groups after 24 hours, as long as sufficient carbohydrate was consumed during recovery. This suggests that as long as you get sufficient carbohydrate within 6 hours of competition, glycogen stores will recover similarly at 8 and 24 hours post-exercise.

Question 36

What is the optimal rate of carbohydrate ingestion for muscle glycogen replenishment after exercise?

Answer 36

The optimal rate of carbohydrate ingestion for muscle glycogen replenishment is approximately 1.2g/min.

Question 37

How might the type of carbohydrate (fructose vs. glucose, low GI vs. high GI) affect muscle glycogen synthesis after exercise?

Answer 37

Muscle glycogen synthesis may be up to 50% slower with fructose or low GI meals initially, as fructose may be preferentially stored as liver glycogen or converted to glucose.

Question 38

When might adding protein to carbohydrate intake after exercise be beneficial for glycogen replenishment? Why?

Answer 38

Adding protein may help if carbohydrate intake is lower than optimal. This is because amino acids can increase insulin release, although carbohydrate remains the limiting factor for glycogen synthesis.

Question 39

What are the overall key points regarding carbohydrate recovery for athletes?

Answer 39

* Total energy intake must match expenditure, or glycogen stores will deplete. * The time to replenish glycogen stores varies (2-6 days). * Some studies have shown good supercompensation after a very short bout of very intense exercise (<24 hours)

Question 40

Summarize the recommended amounts, percentages of daily energy intake (EI), and Glycemic Index (GI) of carbohydrates for pre-competition (days before, 3-4 hours before, 5-60 minutes before), during competition, and after competition, according to the lecture summary.

Answer 40

* Pre (days): Enough for super-compensation = ~6 to 10 g/kg, often >60% of daily EI, Low to Mod GI * Pre (3-4 hours): 200-300 g, Low to Mod GI * Pre (5-60 minutes): 1-1.2 g/kg, Can be high GI, especially if closer to event or in warm-up * During: 30–60 g/h or 0.7 g/kg/hr, 4-8% in drinks, High GI * After: 1.0–1.5 g/kg during the first ~30min + every 2h for 4-6 h, often >65% of daily EI, High GI if rapid replenishment required

Question 41

What is the lecture's summary statement about carbohydrates and athletic performance?

Answer 41

Carbohydrates are an undervalued contributor to performance, and athletes should ingest more while avoiding overconsumption to ensure adequate energy reserves.

Question 42

List the major energy reserves in the body and their approximate energy content (kJ).

Answer 42

* Fat (adipocyte): 337000 kJ * Glycogen (liver): 1500 kJ * Glycogen (muscle): 6000 kJ * Fat (muscle): 15000 kJ * Glucose (blood): 320 kJ * Protein: 150000 kJ (can be a fuel source)

Question 43

How does fat metabolism change with training?

Answer 43

Training leads to: improved ability to oxidize FFA (↑ FFA faster), enhanced capillarization (increased number and density for fat access), improved FFA transport through plasma membrane and mitochondria, increased number of oxidative enzymes, and mitochondrial adaptations (increased density and size).

Question 44

What is the theoretical benefit of a high-fat diet for athletes, especially when muscle glycogen is replenished before exercise?

Answer 44

In theory, high-fat diets could increase the ability to oxidize fat and spare muscle glycogen, particularly if muscle glycogen is replenished before exercise. Some studies showed the same glycogen stores as high CHO diets but increased fat metabolism.

Question 45

What are the ACSM recommendations regarding high-fat diets for athletes? What is the bottom line?

Answer 45

High-fat diets are not recommended by ACSM. While they could theoretically spare glycogen, long-term performance is impaired. The current bottom line is that the recommendations for fat intake are the same as the general population, individualized based on training level and body composition goals.

Question 46

What are the primary roles of proteins in the body?

Answer 46

Proteins have structural and regulatory functions. They can also serve as a fuel source and can be converted to glucose (gluconeogenesis). Proteins make up enzymes and hormones

Question 47

Why is protein important for strength training athletes? What other roles does it play for all athletes?

Answer 47

Protein is important for strength training athletes to rebuild and repair muscle. It is also crucial for tissue maintenance, transporters, and enzymes in all athletes, including endurance athletes.

Question 48

Can you consume too much protein? What are some potential consequences?

Answer 48

Yes, you can consume too much protein. If there is insufficient carbohydrate intake, excess protein can lead to a decrease in glycogen stores, resulting in fatigue and an inability to train as hard. Too much protein can also be excreted as urea and may cause GI distress.

Question 49

What are the building blocks of proteins? What is the difference between essential and non-essential amino acids?

Answer 49

The building blocks of proteins are amino acids (AA). There are 20 amino acids needed for protein synthesis. Essential amino acids are those that must be obtained from the diet, while non-essential amino acids can be synthesized by the body

Question 50

Provide examples of protein sources and their limiting amino acids (if any).

Answer 50

◦ Wheat: lysine ◦ Rice: lysine ◦ Legumes: tryptophan or methionine (or cysteine) ◦ Maize: lysine and tryptophan ◦ Egg, chicken: none

Question 51

What are Branched-Chain Amino Acids (BCAA), and what percentage of muscle protein do they constitute?

Answer 51

Branched-Chain Amino Acids (BCAA) are a group of essential amino acids. They constitute about 20% of muscle protein and are important for muscle synthesis

Question 52

What are the primary reasons for protein breakdown in the body?

Answer 52

Protein breakdown is necessary to: replace damaged proteins, synthesize neurotransmitters (serotonin) or hormones (adrenaline), and provide energy (converted to glucose, ketones, or fatty acids).

Question 53

Describe the process of protein turnover in the body. What percentage of the amino acid pool comes from protein intake daily?

Answer 53

Protein turnover is several times greater than protein intake. Protein intake accounts for only 25% of the amino acids that enter the amino acid pool every day. The remaining 75% comes from protein in the gut, kidney, and liver, which synthesize and resynthesize proteins. Muscle protein turnover is much slower.

Question 54

Briefly explain the Nitrogen Balance Method for estimating protein requirements. What are some limitations?

Answer 54

The Nitrogen Balance Method compares Nitrogen Intake to Nitrogen loss (fecal, urine, sweat, breath (ammonia)). Since about 16% of protein is nitrogen, this balance can estimate protein needs. However, it provides an estimate and often can only measure nitrogen in urine (feasibility), which underestimates total nitrogen excretion (and thus overestimates retention). It can also overestimate needs when eating a high protein diet.

Question 55

What are the average requirement and safe intake of protein for healthy young adults based on the Nitrogen Balance Method?

Answer 55

The average requirement is 0.66g/kg/day of protein, and the safe intake (average requirement + 2 SD) is 0.83g/kg/day. Remember that this is determined under conditions of time energy balance.

Question 56

What are the two main reasons often stated for why protein requirements might be greater for athletes?

Answer 56

The two main reasons are: 1. Amino acids may be oxidized during exercise. and 2. Increased protein synthesis is necessary to repair damage and support training adaptations.

Question 57

According to the study on novice bodybuilders (1.35 vs 2.6 g/kg/day protein intake with resistance training), what were the findings regarding nitrogen balance and changes in muscle mass/strength?

Answer 57

he study showed an increased nitrogen balance in the higher protein intake group (2.6 g/kg/day). However, there was no significant difference in muscle area (CT scan), strength, or total lean mass between the two groups after 4 weeks of training

Question 58

What are the general protein intake recommendations for the general population, endurance athletes, and strength training athletes?

Answer 58

* General population: 0.8 g/kg of body weight per day or 10-35% of Total Daily Energy Intake (TDEI) * Endurance athletes: 1.2 – 1.4 g/kg of body weight per day (possibly more for ultra-endurance), usually not a problem due to higher caloric intake * Strength training athletes: 1.2 – 1.7 g/kg of body weight per day, especially in the early phases of training

Question 59

What are the Dietary Reference Intake (DRI) and a commonly cited average protein intake for athletes? What is a generally recommended upper limit?

Answer 59

The DRI is 0.8g/kg/d. A commonly cited average intake is around 2.05g/kg/d. Some recommendations suggest an upper limit around 1.6g/kg/day for maximizing muscle gains.

Question 60

What are three strategies to favor protein synthesis after exercise?

Answer 60

Strategies to favor protein synthesis include: Co-ingestion with CHO (due to the insulin response), consuming an adequate amount of protein (around 20-25 g?), and appropriate timing of protein intake (peri-exercise). The type of protein (whey vs casein vs soy) may also play a role

Question 61

What did the Esmarck (2001) study on older adults (~74 yr old) find regarding the timing of protein intake (0h vs 2h post-resistance training) and muscle size gains?

Answer 61

The Esmarck (2001) study found that protein supplementation immediately after resistance training led to greater increases in muscle size (1st quadriceps) compared to protein supplementation 2 hours after training in older adults

Question 62

What did a meta-analysis of RCTs (>6 weeks of resistance training + protein supplementation vs. resistance training alone) show regarding gains in one-repetition-maximum (1 RM) in untrained and trained participants?

Answer 62

The meta-analysis showed a significant overall benefit of protein supplementation for 1 RM gains. This benefit was significant in trained individuals but not statistically significant in untrained individuals, suggesting that in untrained individuals, the most important factor is getting out there and lifting weights (resistance training)

Question 63

What did the same meta-analysis show regarding gains in lean body mass (LBM) or fat-free mass (FFM) in untrained and trained participants with protein supplementation?

Answer 63

There were greater overall gains in FFM with protein supplementation. While untrained individuals showed a trend towards increased FFM, the effect was significantly greater in trained individuals. This suggests that adding protein provides additional benefits for FFM gains in trained individuals

Question 64

How does protein supplementation effectiveness for muscle mass/strength gains differ between younger/trained individuals and older/untrained individuals?

Answer 64

Protein supplementation is less effective in older populations. It is more effective in younger and trained individuals compared to older and untrained individuals. In younger adults, it is more beneficial.

Question 65

What is the general recommendation for protein intake to augment muscle mass/strength during prolonged resistance training? Is more always better?

Answer 65

The recommendation is up to 1.6g/kg/day of protein. Consuming protein above this amount does not lead to further gains in FFM. Resistance training itself is the more important stimulus for muscle growth.

Question 66

What is "high quality weight loss" for athletes? What protein intake is recommended during weight loss to achieve this?

Answer 66

"High quality weight loss" for athletes involves the retention of skeletal muscle while promoting fat loss. Current recommendations are 1.6 to 2.4g of protein per kg of body weight per day during weight loss to spare muscle as much as possible

Question 67

How does the degree of energy restriction influence protein intake recommendations during weight loss? What other factors should be considered?

Answer 67

The greater the energy restriction, the greater the protein intake may need to be, within the recommended range. Other factors to consider include the rate of weight loss (faster loss may necessitate more protein) and the type of training (if resistance training is being done, slightly lower protein intake within the range might be sufficient for maintaining muscle mass)

Question 68

What types of protein might be "best" for athletes? Define EAA and BCAA. What is PDCAAS?

Answer 68

Proteins with a higher content of Essential Amino Acids (EAA) and Branched-Chain Amino Acids (BCAA) may be beneficial for athletes, as they are essential for building muscle. PDCAAS (Protein Digestibility Corrected Amino Acid Score) is a measure of protein quality that takes into account both the amino acid profile and the digestibility of the protein. Lower splanchnic AA extraction is also desirable to increase AA availability for muscle protein synthesis. BCAA supplementation is sometimes recommended for older adults or athletes.

Question 69

What are the general roles of micronutrients in the body?

Answer 69

Micronutrients play important roles in: energy production (e.g., B-complex vitamins), bone health (e.g., vitamin D, Calcium), hemoglobin production (e.g., iron), and other functions such as immune function, antioxidant defense, and building and repair.

Question 70

Are the micronutrient needs of athletes different from the general population? Who might be at particular risk for deficiencies?

Answer 70

Athletes may have different micronutrient needs. Athletes with low energy intake or those who exclude one or more food groups may be at particular risk for micronutrient deficiencies.

Question 71

According to ACSM, which micronutrients might be particularly important to consider for athletes?

Answer 71

According to ACSM, indoor/northern athletes could benefit from Vitamin D supplementation. There is a potential role for Vitamin E to reduce oxidative stress, inflammation, and muscle soreness. Minerals that are often low in athletes include calcium, zinc, magnesium, and especially iron

Question 72

Why might iron needs be increased in distance runners? What are some examples of iron loss in athletes?

Answer 72

Iron needs may increase by about 70% in distance runners. This can be due to foot strike hemolysis (breaking of red blood cells as the foot strikes the ground) and "sports anemia" or "dilutional anemia". Prolonged exercise also increases iron losses in feces, urine, and sweat. Female athletes also tend to have reduced iron intake

Question 73

Is supplement use common among athletes? What are some reasons for this?

Answer 73

Yes, supplement use is widespread in athletes. Reasons include attempts to prevent micronutrient deficiencies, as a convenient form of energy/macronutrients, and to directly impact performance

Question 74

What are some important considerations regarding supplements, including protein bars/shakes/pills/powders?

Answer 74

Most supplements are unregulated (look for a DIN) and can contain banned substances. While some supplements like caffeine, creatine, sodium bicarbonate, and nitrate have good evidence of benefit, the effectiveness of many others is not proven or universally beneficial. Athletes need to consider the type of athlete they are.

Question 75

What are some critical questions to ask before taking any supplements?

Answer 75

Critical questions include: * Is the product available, affordable, tolerated, and compatible with your performance goals? * Does your coach, team doctor, personal physician, or sports nutritionist know of and support the use of your choice of supplements? * Is the supplement manufactured and sold by a reliable source with a low risk of cross-contamination with other substances?

Question 76

What is the IOC's take-home message regarding supplements in an athlete's sport nutrition plan?

Answer 76

Supplements can play a small role in an athlete's sport nutrition plan. However, it takes considerable effort and expert knowledge to identify appropriate products, integrate them into a nutrition plan, and ensure the benefits outweigh negative side effects

Question 77

What is the ACSM position stand on fluid replacement during exercise? What level of dehydration is generally considered detrimental to performance?

Answer 77

There is a separate ACSM (2007) position stand on "Exercise and fluid replacement". Dehydration, defined as a loss of >2% of body weight, is considered detrimental to performance

Question 78

What are the general recommendations for water intake before, during, and after exercise?

Answer 78

* Before exercise: 5-7 ml of water / kg at least 4 hours before exercise (e.g., 375 – 525 ml for a 75 kg person). * During Exercise: Develop fluid replacement plans to prevent excessive (<2% body weight reductions from baseline) dehydration. Sweat rates can vary significantly (0.3-2.4 L/h), while the maximum rate of gastric emptying is around 1-1.5 L/hr. Be aware of hyponatremia (low sodium). * After Exercise: If time permits, normal meals and beverages will restore euhydration. For more rapid recovery, drink ~1.5 L of fluid per kg of weight lost. Fluids/foods with sodium will help expedite recovery by stimulating thirst and fluid retention.

Question 79

What factors impact sweat rate?

Answer 79

Sweat rate is related to running time and is also impacted by ambient temperature.

Question 80

What are some important considerations when determining body weight/fat goals for athletes?

Answer 80

Be careful with the tools used to assess body composition (potential for errors). Avoid assigning specific weight or %fat goals for a group, as individual differences should be considered. Provide appropriate support and expertise when suggesting weight loss or gain. More significant weight (fat) loss should preferably take place in the off-season.

Question 81

What are the general nutritional recommendations for weight loss in athletes for "high quality weight loss"?

Answer 81

* Moderate energy restriction. * Gradual loss (0.5-1.0 kg/week, approx 500-1000 kcal/day deficit). * Or increase expenditure with less restriction (difficult for already active athletes). * Appropriate CHO intake for training needs (lower CHO impairs performance). * Maintain/increase absolute protein intake, especially during the 1st week (amino acids may be used for gluconeogenesis initially). Current recommendations are 1.6 to 2.4g PR/kg/day

Question 82

What is a suggested routine for optimizing protein synthesis during weight loss, particularly around exercise?

Answer 82

A suggested routine involves consuming 0.1 g essential AA/kg either immediately prior and/or during the first few hours of recovery. Adding CHO (0.5 g/kg) may be even more effective. This can be obtained from supplements or "real" food like chocolate milk or fruit yogurt

Question 83

What are the general macronutrient recommendations for weight gain in athletes, expressed in g/kg/day and as percentages of total kcals?

Answer 83

* Protein: 1.2–1.7 g/kg/day or about 25% of kcals * CHO: 6.0 g/kg/day or about 55% of kcals * FAT: about 20% of kcals Remember not to over-intake protein for weight gain.