CarbohydratesUnit 3

Stacey Day, MS, RD, LDN

Explain the basic structure and classification of carbohydrates

CHO Classification

Simple CHOs◦ Simple sugars◦ Monosaccharides◦ Disaccharides

Complex CHOs◦ Oligosaccharides◦ Polysaccharides

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Other Polysaccharides Dietary Fiber

◦ Nondigestible◦ Plant sources◦ Soluble versus insoluble

Functional Fiber◦ Nondigestible◦ Commercially produced or isolated

form Dietary + Functional = Total Fiber

Photo Courtesy of Renee Comet/ National Cancer Institute

Artificial Sweeteners

Classified as:◦Non-nutritive◦Nutritive

Generally sweeter than sucrose Must have FDA approval Have “GRAS” status

Artificial Sweeteners

Aspartame◦ NutraSweet

Sucralose◦ Splenda

Saccharin◦ Sweet ‘n Low

Acesulfame-K Tagatose Sugar alcohols

Importance of CHO in Exercise

Serves as an energy source both at rest and during exercise.

Becomes sole source of energy during very intense exercise.

However, stores of CHOs in body are limited.

Importance of CHO in Exercise

Blood glucose levels and the amount of CHO (i.e., glycogen) stored in the muscles can delay fatigue.

What should an athlete eat in the days leading up to competition?

Well-balanced diet in which 55 to 70% of total calories come from CHOs.

Carbohydrate loading?

Photo © Digital Stock

What should an athlete eat in the hours leading up to competition?

0 to 4 hours prior to competition◦Small meal, easily digested, low fiber

◦Low glycemic index Liquid meals Fruit juices Photo © Able Stock

What about CHO consumption during competition?

Types of CHOs◦ Glucose, glucose

polymers, starches◦ Sport nutrition

products Gels Bars Drinks

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What about CHO consumption during competition?

Amount of CHO◦ Depends on rate of

utilization◦ Length of

competition◦ ~60 grams/hour

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How much should an athlete eat after competition?

.5 g of CHO/lb:◦ Immediately after◦ 2 hours after◦ 4 to 6 hours after

Photos © Photodisc

Glycemic Index versus Glycemic Load

Glycemic Index (GI)

Glycemic effect of an isolated food

Based on elevation of blood sugar levels two hours after ingestion

Glycemic Load (GL)

Glycemic effect of the diet

(GI x CHO content per serving) x 100

How useful are GI and GL in sport?