Nutrition for Performance

Question 1

What is used for energy during high intensity exercise?

Answer 1

For high intensity exercise (considered >70% VO2 max) glycogen is the main form of energy used. Once these are depleted the athlete will experience muscular fatigue.

Question 2

Low carb diets and initial weight loss?

Answer 2

When people reduce their carbohydrate intake they deplete their glycogen stores and glycogen is stored with 3-4 parts water so people will initially drop a lot of water weight.

Question 3

Pica?

Answer 3

Eating nonnutritive substances for a period of at least 1 month. Associated with iron deficiency.

Question 4

Meals upon waking for athletes?

Answer 4

A precompetition meal for aerobic endurance athletes may be very important after waking because blood sugar levels are low and liver glycogen stores are substantially reduced.

Question 5

Post-competition and salt?

Answer 5

Sodium is essential for helping the body retain fluid so if sweat losses are substantial, the athlete should replenish through a sports drink or with foods that contain sodium.

Question 6

What are the different glycogen stores used for?

Answer 6

Glycogen stored in the liver is used for the entire body, that in the muscle is only used by the muscle.

Question 7

Endurance athletes and low carb diets?

Answer 7

Endurance athletes who aren’t chronically adapted to a low-carb diet and start exercise with depleted glycogen stores will break down muscle to use protein for energy. Therefore, a high carb preexercise meal can help attenuate the breakdown of muscle. Over time, adaptation to chronic consumption of a low carbohydrate diet increases reliance on fat as a fuel source during exercise.

Question 8

Basal metabolic rate and is total energy expenditure?

Answer 8

65-70% of daily energy expenditure.

Question 9

Protein needs after resistance training?

Answer 9

Maximal stimulation occurs with 20-25 g of a high-quality, high-leucine (2-3 grams or 0.05 g/kg body weight), fast protein in younger individuals while 40 g or more may be necessary for older adults. Supplementing with protein after exercise led to small to moderate increases in muscle hypertrophy compared to not supplementing.

Question 10

How soon should aerobic endurance athlete eat carbs after training/competition?

Answer 10

You can do it immediately or up to 2 hours after a glycogen-depleting event and replenish carbs over a 24 hour period but athletes who train multiple times a day need to consume carbs immediately. Protein should be taken in as well to help with muscle repair and it can increase rate of glycogen storage if carbohydrate intake is inadequate.

Question 11

How to calculate BMI?

Answer 11

Kg / meters2 or (pounds/inches2) x 703

Question 12

Carb loading suggestions?

Answer 12

3 days of a high carb diet in concert with tapering exercise the week before competition and complete rest the day before the event. There should be adequate calories but 8-10 grams of carbs per kg of body weight. This should increase glycogen stores 20-40% above normal. Higher intakes of 10-12 grams per kg of body weight have sometimes been suggested for runners during the 36-48 hours before a marathon.

Question 13

Fluid recommendations during training/competition for athletes (different ages)?

Answer 13

Children: 5 ounces every 20 minutes (water or sports drink)
Adolescents: 9 ounces every 20 minutes (water or sports drink)
Adults: For endurance athletes, each hour (30-90 grams of carbs)

Question 14

Most important factors in losing weight?

Answer 14

There is no difference in weight loss between low carb vs. low fat diets, what is important is decreasing caloric intake. Athletes who want to maintain muscle and lose body fat while dieting should consume about 1.8 to 2.7 g protein/kg body weight per day and reducing calories by 500 calories/day.

Question 15

How much glycogen is stored in the body?

Answer 15

15 grams of glycogen per kilogram of body weight.

Question 16

General guidelines for precompetition meals (not amounts)?

Answer 16

Should be smaller quantities when close to competition, familiar to the athlete, low in fat/fiber so they empty from the stomach rapidly, and moderate in protein (promotes longer satiety). High or low glycemic index carbs are equivocal, no advantage of one vs. the other.

Question 17

Total energy expenditure of food intake?

Answer 17

The thermic effect of food (digestion, absorption, metabolism, storage) accounts for 10-15% of total calories burned each day.

Question 18

Optimal sports drink?

Answer 18

20-30 mEq of sodium (460-490 mg) per liter, 2 to 5 mEq of potassium (78-195 mg) per liter, and carbohydrate concentration of 5-10%.

Question 19

Carbohydrates and strength/power sports?

Answer 19

Athletes in strength/power sports rely on both blood glucose and glycogen for energy during competition. A single bout of resistance training can lead to significant reductions in glycogen and impair force production and isometric strength. These athletes need to restore their glycogen levels prior to the next bout of exercise. They should focus on high GI carbs after exercise if they plan on exercising again in the next 24 hours.

Question 20

Basal metabolic rate versus resting metabolic rate?

Answer 20

BMR is measure after an overnight fast and with the subject resting supine and motionless. RMR does not require fasting and is usually 10-20% higher due to increased energy expenditure from recent food intake and physical activity.

Question 21

The rate of muscle protein synthesis and breakdown after resistance training?

Answer 21

The rate of synthesis in 3 hour period after exercise increased above resting rates by 112%, 65% over 24 hour period, and 34% over 48 period. Muscle breakdown also increased by 31% and 18% in the 3 and 24 hour periods after exercise (respectively) and returned to baseline by 48 hours.

Question 22

Carbs during aerobic sports?

Answer 22

Studies show carb intake ranging from 28 to 144 grams per hour can decrease reliance on glycogen stores, extending time to exhaustion. Exogenous carb oxidation rates don’t exceed 1-1.1 grams per minute, likely due to the rate of glucose absorption and limited delivery rate of 1 gram/minute of glucose into the bloodstream. If you only consume one type of carb your digestion will be limited, as the intestinal transporter for that carb will become saturated. Therefore, it is recommended to consume multiple types of carbs (sucrose, glucose, maltose, fructose, etc.).

Question 23

Problem with BMI?

Answer 23

It can overestimate body fat in athletes/those with muscular builds and underestimate fat in older individuals or those that have lost muscle.

Question 24

Nutrition for endurance athletes (specifics)?

Answer 24

1. 8-10 g of carbs and 1.0-1.6 g of protein per kg of body weight per day, especially if training 90 or more minutes.
2. When eating 4 hours before competition include 1-4 g/kg body weight for carbs and 0.15-0.25 g/kg protein
3. Should consume 28-144 g of multiple types of carbs per hour during prolonged aerobic endurance exercise to prolong time until exhaustion
4. After exercise 1.5 g/kg body weight for carbs within 30 minutes. As a general guideline at least 10 g of protein within 3 hours after exercise

Question 25

Total energy expenditure of physical activity?

Answer 25

Second largest energy expenditure after BMR and accounts for 20-30% of total daily calories.

Question 26

Carbohydrates and high-intensity, intermittent sports?

Answer 26

Fully replacing muscle glycogen before a subsequent bout of exercise/competition may prolong time until fatigue and improve performance. Protein is good to take in but it will not affect performance in a subsequent bout of exercise.

Question 27

Anorexia Nervosa?

Answer 27

Characterized by a distorted body image and an intense fear of gaining weight or becoming fat, leading those with this disease to excessive calorie restriction and severe weight loss. Two subtypes are restrictive (no purging) and binge-eating or purging.

Question 28

Carbohydrate loading for power athletes?

Answer 28

Research shows no difference in power performance but they should have adequate glycogen stores.

Question 29

Plus and minus of concurrent training?

Answer 29

When doing endurance training and strength training together, this will blunt strength gains compared to doing strength training alone but will result in improvement in endurance performance.

Question 30

Equations for caloric needs?

Answer 30

Cunningham and Harris-Benedict equations. The Harris-Benedict looks at sex, body weight, height, and age to calculate RMR. This can then be multiplied by an activity factor to predict calorie needs. The Harris-Benedict doesn’t take into account muscle mass but the Cunningham equation takes the same variables into account but also includes fat-free mass, making more applicable to athletes. After using the Cunningham equation an activity factor can be used to estimate total daily caloric needs.

Question 31

BMI categories?

Answer 31

<18.5 = Underweight; 18.5-24.9 = Normal; 25-29.9 = Overweight; 30-34.9 = Class 1 Obesity; 35.0-39.9 = Class 2 obesity; >40 = extreme (class 3) obesity.

Question 32

Carbs and protein when doing concurrent training?

Answer 32

Take carbs after endurance training and pre-lift to suppress muscle breakdown. Also, if doing exercise greater than 2 hours in length you should be taking protein to support greater muscle protein synthesis.

Question 33

Rumination Disorder?

Answer 33

Chewing, reswallowing, or spitting of regurgitated food. Must display this behavior for at least one month.

Question 34

How do carbs help with protein breakdown?

Answer 34

Carbs have no effect on muscle protein synthesis but they do help attenuate acute protein breakdown due to resistance exercise.

Question 35

Glycogen synthesis?

Answer 35

Occurs in 2 distinct phases. The first phase is independent of insulin and lasts 30-60 minutes, this synthesis occurs rapidly. The second phase lasts several hours and synthesis occurs at a much slower pace. Glycogen synthesis occurs at a rapid rate when large amounts of carbs (1-1.85 grams/kg body weight per hour) are consumed immediately after exercise or competition at regular intervals (15-60 minutes) for up to 5 hours.

Question 36

Nutrition for strength or hypertrophy (specifics)?

Answer 36

1. Consider supplementing with carbs before and during competition to maintain strength and minimize muscle breakdown
2. Consume 5-6 g of carbs/kg body weight each day. 1.4-1.7 g/kg protein.
3. Consume 30-100 g of higher glycemic carbs after training to reduce muscle breakdown. 20-25 g protein after for younger individuals and 40 g or more for older adults.

Question 37

Binge Eating Disorder?

Answer 37

Characterized by repeated episodes of at least 1x/week for 3 weeks of uncontrolled binge eating.

Question 38

How should BMI be used?

Answer 38

Not as a diagnostic tool but as a screening tool

Question 39

Bulimia Nervosa?

Answer 39

Characterized by recurrent consumption of food in greater amounts than usual followed by one or more of the following: purging, intense exercise, laxative use, diuretic use. Must occur at least 1x/week for 3 months. They are usually more likely to be of normal weight.

Question 40

Protein at meals and how often?

Answer 40

After resistance training your muscles have increased sensitivity to amino acids for 24 to 48 hours and the anabolic effect of a meal lasts 3-5 hours so experts recommend consuming at least 20-30 g of protein per meal and eating meals every 3-4 hours.

Question 41

Challenge with carb loading and females?

Answer 41

The main challenge seems to be overall daily calorie intake. Women who consume less than 2,400 calories per day may find it difficult to consume more carbs. In order to increase glycogen stores, they will probably have to increase their calorie intake on top of the higher carb diet.

Question 42

Calorie guidelines to gain weight?

Answer 42

A general guideline is to consume 500 additional calories/day to gain weight. 1.5-2.0 g of protein / kg of body weight needed to maximize lean muscle gains. Creatine monohydrate should also be considered because of its effect on gaining lean body weight.

Question 43

Sugar alcohols?

Answer 43

These should be avoided by athletes around training. Their chemical structure resembles both sugar and alcohol and are a carbohydrate that is not completely absorbed in the gut. Consequently, they can cause gas, bloating, and cramping and have a laxative effect.

Question 44

Primary purpose of precompetition meal?

Answer 44

Provide sufficient fluid intake to maintain hydration and also sufficient carbs to maximize blood glucose and stored glycogen, all while satisfying thirst/hunger.

Question 45

General nutrition recommendations for aerobic endurance athletes (specifics)?

Answer 45

1. Prehydrate several hours before exercise (USG <1.020)
2. For those that have anxiety or get nauseated easily, consider eating about 4 hours before competition. If doing this 4 hours before, consider including about 1-4 g of carbs per kg of body weight and 0.15 to 0.25 g of protein per kg of body weight. Should consume 5-7 ml of water or sports drink per kg of body weight.
3. If precompetition meal is consumed 2 hours before exercise, athletes should aim for about 1 g of carbs per kg of body weight and sip 3-5 ml of fluid per kg of body weight.
4. When food consumed 1 hour before start of competition, intake 0.5 g of carbs per kg of body weight and you may want to consider use of liquid carbs as these are emptied from the stomach faster than solid carbs.

Question 46

Estimated daily calorie needs of male/female athletes by activity level?

Answer 46

Male

Light - 17/lb
Moderate - 19/lb
Heavy - 23/lb

Female

Light - 16
Moderate - 17
Heavy - 20