Why do you even need a post workout carb?
-Replenish muscle cell and liver glycogen stores: this is our primary energy source, especially during shorter, higher intensity bouts of exercise. Our blood sugar is often quickly utilized and subsequently sugars must be liberated from their stores in the muscle/liver.
-Even taking a PRE workout carb is often a wise choice (hypertrophy, endurance)
-The research is mixed: we oxidize carbohydrates at a rate of 1-1.75g/min during exercise.
-The subsequent insulin response, in addition to the one caused by whey protein, helps shuttle amino acids into our muscle cells. IMPORTANT!
What are the BEST choices?
NOTE: Glucose is the ONLY type of carbohydrate that can be oxidized for energy by skeletal muscle. Ie) everything else must be converted to glucose, which takes time.
Whole foods:
-Dates are relatively high in glucose (which does not need to be metabolized in the liver, and therefore can be shuttled directly to the muscle cell)
-Banana’s are high in fructose, which has to be metabolized in the liver FIRST, and then shuttled to the muscle, making it slightly less than ideal. It is good, but not the best choice. Often this is the ideal choice simply because they are cheap and easy to find.
Dextrose/glucose powder or glucose sport drink:
-Dextrose and glucose actually have the same molecular structure; they are simply mirror images of each other.
-they cause a VERY significant insulin response (spike) which helps shuttle these simple sugars, and post workout amino acids, to our muscle cells.
Multiple Sources:
-If exercise is PROLONGED (ie. a whole grain or banana AND a fast absorbing simple sugar)
Sources:
Ribose versus dextrose supplementation, association with rowing performance: a double-blind study.
http://www.ncbi.nlm.nih.gov/pubmed/16377979
Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle.
http://www.ncbi.nlm.nih.gov/pubmed/21135051
Effect of low- and high-glycemic-index meals on metabolism and performance during high-intensity, intermittent exercise.
http://www.ncbi.nlm.nih.gov/pubmed/21116017
Preexercise ingestion of carbohydrate plus whey protein hydrolysates attenuates skeletal muscle glycogen depletion during exercise in rats.
http://www.ncbi.nlm.nih.gov/pubmed/21050718
Metabolic factors limiting performance in marathon runners.
http://www.ncbi.nlm.nih.gov/pubmed/20975938
Glycemic index in sport nutrition.
http://www.ncbi.nlm.nih.gov/pubmed/20234033
Human muscle glycogen metabolism during exercise. Effect of carbohydrate supplementation.
http://www.ncbi.nlm.nih.gov/pubmed/9458524
Effect of the glycaemic index of a pre-exercise meal on metabolism and cycling time trial performance.
http://www.ncbi.nlm.nih.gov/pubmed/19230767
Carbohydrate and exercise performance: the role of multiple transportable carbohydrates.
http://www.ncbi.nlm.nih.gov/pubmed/20574242
Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, guidelines and directions for future research.
http://www.ncbi.nlm.nih.gov/pubmed/10870867
Exogenous carbohydrate utilisation: effects on metabolism and exercise performance.
http://www.ncbi.nlm.nih.gov/pubmed/9406448
Nutritional manipulations before and during endurance exercise: effects on performance.
http://www.ncbi.nlm.nih.gov/pubmed/1406206
Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise.
http://www.ncbi.nlm.nih.gov/pubmed/9232557
High-fat diet versus habitual diet prior to carbohydrate loading: effects of exercise metabolism and cycling performance.
http://www.ncbi.nlm.nih.gov/pubmed/11402254
