Wk 2 Carbs

Question 1

Metabolic pathways

Fats, carbs, proteins –> ?

Answer 1

Fats → FFAs + glycerol
Carbs → glucose
Proteins → amino acids

Question 2

of calories per gram - carbs

Answer 2

4 kcals

Question 3

Classification of carbs is based on number of _ _ _

Answer 3

Single sugar units

Question 4

Sugars (1-2)

Answer 4

Monosaccharides
Disaccharides
Sugar alcohols

Question 5

Oligosaccharides (3-10)

Answer 5

Malto-oligosaccharides

Non-a-glucan oligosaccharides

Question 6

Polysaccharides (>10)

Answer 6

Starch

Fiber

Question 7

Monosaccharides

Answer 7

Glucose, fructose, galactose

Question 8

Disaccharides

Answer 8

Sucrose, maltose, lactose

Question 9

Sugar alcohols

Answer 9

Sorbitol, mannitol, malitol

Question 10

Malto-oligosaccharides

Answer 10

Maltodextrins

Question 11

Non-a-glucan oligosaccharides

Answer 11

Inulin, polydextrose, raffinose

Question 12

Starches

Answer 12

Amylose, amylopectin, modified starch

Question 13

Fibers

Answer 13

Cellulose, pectin, B-glucan

Question 14

Characteristics of high quality complex carbs

Answer 14

minimally processed, contains all nutrients and fiber, made of the whole grain (bran, endosperm and germ)

Question 15

Characteristics of low quality complex carbs

Answer 15

extensively processed to remove bran and germ, much less fiber and fewer naturally occurring vitamins and minerals than high quality carbs

Question 16

Role of carbs in exercise

Answer 16

Important role for performance in; prolonged, intermittent intensity and high intensity exercise, and for recovery in sport.

Question 17

Carbs for exercise - location, amount and notes

Answer 17

Liver; 75-100g. Supports blood glucose level at rest and during exercise, depleted by overnight fast to <20g.
Muscle; 300-400g. Supplies glucose for muscle - lacks G6P, use increases with exercise intensity. Depletion: depends on exercise intensity
Blood; 4g blood glucose (3.9-5.5 mmol/L). Used by brain (and exercising muscle, as muscle glycogen becomes depleted)

Question 18

Carb reserves are ___ g - ____ kcals

Answer 18

Carb reserves are 500g - 2000cal

Question 19

Fat reserves are…

Answer 19

Almost unlimited

Question 20

Roles of CHO in the athletes diet

Answer 20

Carbs sustain daily training, health and wellbeing, replenish liver and muscle glycogen stores, requirements vary depending on training intensity and duration, should be consumed throughout the day, should be altered day by day to reflect training load,

Question 21

Training load and CHO intake (g/kg/d):

Answer 21

light - 3-5 (low intensity/skill based), moderate (60 min) - 5-7, endurance (1-3 hr of moderate/high) - 6-10, extreme (>4-5 hr mod/high) - 8-12

Question 22

Sedentary people need _ g CHO every day.

Answer 22

Sedentary people 130g CHO every day.

Question 23

Training with low carb stores leads to…

Answer 23

Increase in signalling enzyme AMPK - stimulates energy generating processes; decreases energy consuming processes. Activates transcriptional factors and co activators - PGCs. upregulates expression of genes related to mitochondrial biogenesis, and angiogenesis. Carb essentially switches off AMPK activation.

Question 24

Low carb training - types and methods

Answer 24

Training 2x per day; limited or no carb intake between two training sessions - may incr expression of relevant genes
Training fasted; training after an overnight fast. Muscle glycogen may be ok but liver glycogen will be low.
Training w low exogenous carb availability; little or no carb ingested during exercise. This will exaggerate the stress response
Withholding carbs during recovery; none or very little carb post exercise to prolong the stress response
Sleep low; train late in the day with no carb before sleep. Lowers liver and muscle glycogen for several hours

Question 25

Low carb training - drawbacks

Answer 25

possible negative impact on muscle protein synthesis. Will impact work capacity and quality of high intensity training sessions. May impact the immune system. Not advisable for athletes under 18. Psychological effects.

Question 26

Pre-exercise meal - objectives

Answer 26

Incr/replenish muscle glycogen, restore liver glycogen after an overnight fast
Contribute to hydration, prevent hunger, easily digested, psychological boost?

Question 27

Pre-exercise meal - guidelines

Answer 27

• Main meal 2-3 hrs before exercise lasting >60 min; to allow for gastric emptying before exercise
• Provide 1-4g CHO/kg before exercise - restore liver glycogen. increase/replenish muscle glycogen
• Contain fluid - contribute to hydration
• Avoid very high fat and spicy foods - facilitate gastric emptying, minimize GI distress
• Moderate in protein - filling?
• 30-60 min before exercise top up with high GI carbs - quick source of glucose

Question 28

CHO during exercise - types of exercise w/ timing and corresponding CHO

Answer 28

• Brief exercise - <45 min: not required
• Sustained high intensity exercise - 45-75 min: small amounts incl mouth rinse for 10s, consider dental hygiene
• During endurance exercise incl stop and start sports - 1-2.5 hr: 30-60 g/h to spare muscle glycogen and maintain BG levels
• Ultra endurance exercise - <2.5-3 hr: up to 90 g/h. Use of different intestinal transporters may incr overall CHO absorption. Maltodextrin - fructose, glucose - fructose, glucose - sucrose - fructose