Carbohydrates and Their Impact on Energy and Performance

These flashcards cover essential vocabulary related to carbohydrates, their types, functions, and implications on energy and exercise based on the lecture notes.

Monosaccharides

Simple sugars that are the building blocks of carbohydrates, including glucose, fructose, and galactose.

What are the Monosaccharides?

Glucose, fructose, galactose

Disaccharides

Carbohydrates formed from two monosaccharides; examples include sucrose and lactose.

Disaccharides: Sucrose

Glucose + Fructose - table sugar

Disaccharide: Lactose

Glucose + Galactose - milk sugar

Disaccharide: Corn syrup

Glucose + Fructose - soft drinks

Glycemic Index

A measure of how quickly a food raises blood sugar levels after consumption.

Complex Carbohydrates

Starches found in plant foods.

Fuel and Nourishment in CHO

Sugary soft drinks, polymer sports drinks, fruits, vegetables, and grains

Is CHO fattening?

Carbohydrates are less calorie-dense than fats, with CHO providing 16 kcal/tsp and fat providing 36 kcal/tsp. Body preferentially burns CHO and stores fat

Glycemic Index

Based on how 50g (200kcal) of CHO will affect blood sugar levels after an overnight fast

High Glycemic Index Foods

Foods that rapidly increase blood sugar levels, such as sports drinks and jelly beans.

Glycogen Storage

Average 150lb man has about 1800kcal stored CHO

Muscle glycogen - 1400kcal

Liver glycogen - 320kcal

Blood glucose - 80kcal

CHO in muscle used during exercise

CHO in liver released into bloodstream

Fat storage

Average lean 150lb man has 60,000-100,000kcal of stored fat

Why fat cannot be used exclusively as fuel?

Because muscles need a certain amount of CHO to function well

Low level exercise

Fat primary source of fuel

Light to moderate

Stored fat provides 50-60% of fuel

Hard exercise

Rely primarily on glycogen stores

Carbohydrate Loading

A dietary strategy aimed at increasing glycogen stores in the liver and muscles to enhance performance and delay fatigue.

Glycogen

A stored form of glucose in the muscles and liver, utilized for energy during exercise.

Glycemic Index

A measure of how quickly a food raises blood sugar levels after consumption.

Complex Carbs: Veggies

Sweet when young, starchy when ripen

Complex Carbs: Fruits

Starchy when young, sweeter when ripen

How are carbohydrates processed in the body?

All carbs are digested into glucose and then burned for energy or stored for future use in the muscle and liver glycogen.

Carbs Rule

1. Need CHO to fuel your muscles
2. Burn CHO during hard exercises
3. When dieting to lose weight, energize with fiber rich cereal, whole grains, potatoes, and CHO-dense veggies but decrease intake of butter, margarine, mayo
4. For added satiety, enjoy minimally processed CHO in combination with protein

Why fat cannot be used exclusively as fuel?

Because muscles need a certain amount of CHO to function well.

Carbohydrate Loading

A dietary strategy aimed at increasing glycogen stores in the liver and muscles to enhance performance and delay fatigue.

Muscle Glycogen Storage: Influence of Training

Biochemical changes during training influence the amount of glycogen stored in muscles.

Well-trained vs. Untrained Muscle Glycogen Stores

Well-trained muscles store 20-50 more glycogen than untrained muscles (Costill et al., 1981).

Muscle Glycogen Stores per $100 ext{ g}$ ($3.5 ext{ oz}$) of muscle

• Untrained muscle - $13 ext{ g}$

• Trained muscle - $32 ext{ g}$

• CHO-loaded muscle - $35-40 ext{ g}$

Ice Hockey Study: Characteristics

Relies on muscular strength and power.

Ice Hockey Study: Glycogen Decline

Muscle glycogen stores decline 38-88% during ice hockey.

Ice Hockey Study: Recommended CHO intake

55-65g CHO recommended for ice hockey.

What is carbohydrate loading?

A dietary technique designed to promote a significant increase in the glycogen content in both liver and muscles in an attempt to delay onset of fatigue.

Where can I find information on CHO content in common foods?

Table 6.6 on page 133-134.

What are the steps in Clark's 9-Step CHO Loading Plan?

1. CHO load daily
   • $2.5-3.5 \text{ g CHO/lb}$ ($6-10 \text{ g/kg}$)
   • (Refer to Table 6.4 on page 123)
2. Taper your training
3. Eat enough protein
   • $0.5-0.8 \text{ g/lb}$ ($1.2-1.7 \text{ g/kg}$)
4. Don't fat load
   • $20-25\%$ kcal from fat
5. Pay attention to fiber intake
6. Plan meal times carefully
7. Drink extra fluids
8. Be sensible about your selections
9. Eat breakfast on day of event

When does "Bonking" occur?

"Bonking" occurs when liver glycogen is depleted, leading to insufficient blood sugar levels for brain function.

What is the role of liver glycogen concerning blood sugar levels?

Liver glycogen feeds into the bloodstream to maintain normal blood sugar, which is essential for 'brain food'.

What happens if you do not consume enough carbs, especially during endurance activities?

You 'hit the wall,' which refers to a sudden and severe fatigue or loss of energy due to the depletion of glycogen stores.

Recommended CHO intake for endurance athletes

$3-5 \text{ g/lb}$ ($6-10 \text{ g/kg}$)

How do CHO needs differ for fitness exercisers compared to endurance athletes?

Fitness exercisers need less CHO than endurance athletes.

Recommended percentage of daily calories from CHO

$45-65\%$ of daily calories.