2.11.08 Carbohydrates

CHO metabolism pg. 4 pkt.

During Glycolysis (breakdown of glucose to pyruvate) 6 carbon chain is broken into 2-3 carbon chain pyruvates.

Energy is given off to create 3 ATP. If the body's blood glucose is not adequate, liver and muscle glycogen can be converted to glucose.

Anaerobic glycolysis- pyruvate to lactate. Recovery- slow recovery - lactate goes back to pyruvate.

Aerobic glycolysis- pyruvate to acetyl CoA

Kreb Cycle- CO2 released, exhaled. H ions shuttled to mitochondria

ETS- Byproduct is water. large release of energy (32 ATP)

CHO/Lipids

Power-walking 1 mile=100 kcals - x amount from CHO = y amount from lipids

What dictates how much CHO/lipids we use?
1. Intensity
2. Duration
3. Diet Prior to exercise

I= 1/D (inverse relationship) (as intensity increases, duration decreases)

as I increases, CHO usage increases, lipid usage decreases
as D increases, CHO usage decreases, lipid usage increases

Resting State- 60% lipids burned (body prefers to use lipids)

Diet Prior to Exercise

The body tends to use what is available to it.
But, for performance- you will fatigue @ depletion of muscle glycogen, except for the one case when very high intensity for very low duration leads to build up of H ions.
However, in this case, CHO are very important to recovery.

CHO is the most important for ANY exercise program.

CHO stores
Muscle glycogen-most important to performance
liver glycogen
blood glucose

fatigue sets in as muscle glycogen is deleated (except for highest intensity).

5 Factors for how we use Muscle Glycogen
1. Intensity
2. Duration
3. Mode -site specific- muscle glycogen doesn't convert to blood glucose-must be used
in that specific muscle.
4. Fitness level-better aerobic shape-better you use Lipids
5. Fast twitch vs. slow twitch muscle use-specific to I and D. FT-Primarily anaerobic,
ST-Primarily aerobic


Optimizing Performance


Pre Event Meal

*Mixed diet, 3-4 days before switch to high CHO diet (65-70% kcals from CHO) No exhaustive exercise. Increases MG stores by 40%.

*Mixed diet, 3-4 days before, perform an exhaustive workout, increase CHO intake, Increases MG stores by 100% (doubles)

* Classical Procedure
1week before- exhaustive exercise, low CHO diet, high Fats/proteins.
3-4 days before, perform exhaustive exercise, switch to high CHO diet. Increases MG stores by 200%

* High CHO diet all the time


Goal of Pre-game meal
top off MG level & normalize BG level.

Solid meal 2.5-3 hrs. before event
liquid meal 1-1.5 hrs. before- water based meals are easier to digest

High CHO less of the refined sugars: lightly buttered toast, cereal, etc.
Avoid high fiber meal

15-20 min. before (book says 10 min.) eat refined sugar-won't get reactive hypoglycemia


During the Event
liquid usually
under 60-90 min- water

>90 min-glucose drink
Gatorade (6-8% solution), ACSM (4-8%), Author 5-10%, Costill 2-2.5%


Post Game
Chocolate milk

Sooner the better within 1-2 hours is optimal

High CHO

More refined the quicker

still no insulin reaction

3:1 ratio with protein
(probably due to the extra calories provided by the protein)

Replenishing MG

Also facilitating Muscle growth.