Carbohydrates Discussion Forum
Lisa
carbohydrates.pptxCarbohydrates
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
Photos © Photodisc
3
Simple Carbohydrates
Monosaccharides
Glucose
Galactose
Fructose
Disaccharides
Sucrose
Lactose
Maltose
4
Complex Carbohydrates
Oligosaccharides
Short chains
3 to 10 sugars
Maltodextrin
Corn syrup
Polysaccharides
Long chains
> 10 sugars
Starch
Glycogen
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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
6
Artificial Sweeteners
Classified as:
Non-nutritive
Nutritive
Generally sweeter than sucrose
Must have FDA approval
Have GRAS status
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Artificial Sweeteners (continued)
Saccharin
Sweet’N Low
Aspartame
NutraSweet
Acesulfame-K
Sucralose
Splenda
Tagatose
Sugar alcohols
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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
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Functions of CHOs (continued)
Metabolic primer for fat metabolism:
Provides critical intermediates for energy production from fat 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
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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
Weight gain
12
Carbohydrate Intake
Recommendations
5 to 10 g/kg of body weight
Usually 45% to 65% of total daily calories
May go as high as 75%
Recommendations will change based on an athlete’s stage of training and competition schedule
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Carbohydrate Sources
Whole grains
Vegetables and fruits
Pros and cons of various forms
Dairy and dairy alternative products
Beans, lentils, nuts, seeds, and soy products
Sweets
Photo © PhotoDisc
14
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) ÷ 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?
Photo © Digital Stock
18
What should an athlete eat in the hours leading up to competition? (continued)
4 to 24 hours prior to competition
Balanced high-CHO meals/snacks
Familiar foods
CHO = ~ 60% to 70% of total calories
Photo © Photodisc
19
What should an athlete eat in the hours leading up to competition? (continued)
0 to 4 hours prior to competition
1 to 4.5 grams CHO/kg body weight
Easily digested, low fiber
Complex carbohydrates
Low glycemic index
Experiment in training
Photo © Able Stock
20
What about CHO consumption during competition?
Types of CHOs
Glucose, glucose polymers, fructose, starches
Sport nutrition products
Gels
Bars
Drinks
Photo © Photodisc
21
What about CHO consumption during competition? (continued)
Amount of CHO
60–70 grams per hour
Individual tolerance will vary
Timing of intake
Begin soon after onset
Continue at regular intervals
Photo © ComstockImages/AlamyImages
22
What should an athlete eat after competition?
CHO consumption after exercise is important for glycogen replenishment.
CHO should be consumed as soon as possible after exercise.
Solid or liquid forms are acceptable.
High glycemic index sources are preferred.
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How much should an athlete eat after competition? (continued)
1.2 g of CHO/kg
Immediately after
Every hour for 3–4 hours
Photos © Photodisc
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Nutrition Facts http://youtu.be/MrdCBqFYDyo
25
Dietary analysis
software and
web sites are
quick and easy
tools to
determine
nutrient and
energy contents
of commonly
eaten foods.
Government-Sponsored
Dietary Analysis Web sites
MyPlate Super Tracker
https://www.choosemyplate.gov/SuperTracker/default.aspx
“What’s in the Food You Eat Search Tool”
www.nal.usda.gov/fnic/foodcomp/search/
Using Dietary Analysis Software
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