CarbohydratesChapter 31What are carbohydrates (C.docx
1. Carbohydrates
Chapter 3
1
What are carbohydrates (CHO)?
Molecules
Carbon
Hydrogen
Oxygen
Formed by plants via photosynthesis
Stored in plants as starch
2
CHO Classification
Simple CHOs
Monosaccharides
Disaccharides
Complex CHOs
Oligosaccharides
Polysaccharides
3. Polysaccharides
Long chains
> 10 sugars
Starch
Glycogen
5
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
6
Artificial Sweeteners
Classified as:
Non-nutritive
Nutritive
Generally sweeter than sucrose
Must have FDA approval
Have GRAS status
4. 7
Artificial Sweeteners (continued)
Saccharin
Sweet’N Low
Aspartame
NutraSweet
Acesulfame-K
Sucralose
Splenda
Tagatose
Sugar alcohols
8
Functions of CHOs
Energy source
4 kcals/gram
Primary energy source for the body, especially during exercise
Only energy source for high-intensity anaerobic exercise
Energy source for the cells of the Central Nervous System
9
Functions of CHOs (continued)
Metabolic primer for fat metabolism:
Provides critical intermediates for energy production from fat
5. breakdown
Prevents ketosis
Prevents protein catabolism in body:
Decreases gluconeogenesis
Spares muscle tissue
10
CHOs and Health
Phytochemicals
Found in plants
Antioxidants
Enhance immune function
Fiber
Soluble
Lowers cholesterol
Insoluble
Adds bulk to intestinal contents
Decreases transit time of intestinal contents
Draws water into intestinal contents
11
CHOs and Health (continued)
Fiber may be related to:
Reduced risk of heart disease (cholesterol lowering)
Reduced risk of cancer (phytochemicals, antioxidants, and
decreased intestinal transit time)
Improved weight management (feeling of fullness)
Simple sugars (refined sugars) may harm health:
Dental caries
7. 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) ÷ 100
How useful are GI and GL in sport?
15
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.
16
Importance of CHO in Exercise
Blood glucose levels and the amount of CHO (i.e., glycogen)
stored in the muscles can delay fatigue.
17
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?