Primary fuel ssu/images/High%20Glyc.jpg 20food%20shot%20@%20350.jpg.
-
Upload
bertina-harvey -
Category
Documents
-
view
212 -
download
0
Transcript of Primary fuel ssu/images/High%20Glyc.jpg 20food%20shot%20@%20350.jpg.
Carbohydrate (CHO)Primary fuel
http://www.medic.usm.my/~ssu/images/High%20Glyc.jpghttp://www.birnstihl.com/photos/product/Carbohydrate%20food%20shot%20@%20350.jpg
Carbohydrates are organic compounds that contain carbon, hydrogen and oxygen in various combinations
Simple, complex and dietary fibre
Definition
Storage and transport of energy
Structural components (e.g. cellulose in plants, cartilage in animals)
Primary energy/ fuel for athletes.
Roles of Carbohydrates (CHO)
Each gram of CHO contains approximately
c.f 4 calories per gram PROTEIN 9 calories per gram FAT
Energy content
4 calories
Distribution of CHO energy
P13, McArdle Katch & Katch (2001)
*average 80kg person
Disaccharides and monosaccharide's There are three main monosaccharide's
◦ Glucose◦ Fructose◦ Galactose
Combining two monosaccharide's makes a disaccharide◦ Sucrose◦ Lactose◦ Maltose
Simple Carbohydrates (sugars)
Ingestion of disaccharides
Lactose
Galactose
Glucose
Sucrose
Fructose
Glucose
Maltose
Glucose
Glucose
Storage form of CHO Generally formed when three or more glucose
molecules combine to make a polysaccharide
Starches can be plant starches or animal starches (glycogen)
Glucose polymers are polysaccharides prepared commercially by hydrolysis of starch (maltodextrin and polycose)
Complex Carbohydrates (starches)
Complex carbohydrates is A term used to describe foods high in starch, such as bread, cereals, fruits and vegetables as contrasted to simple carbohydrates such as table sugar
Complex versus Simple?
Williams, 2005
Non starch polysaccharide Structural part of the plant Fibre can be soluble or insoluble Fibre is not digested by humans Fiber includes cellulose, hemicellulose
(insoluble), pectin's, gums and mucilage's (soluble), and nonpolysaccharide lignin's, cutins and tannins (not carbohydrates)
Fibre
Foods which have been processed by machinery that strips the bran and germ from the whole grain
The process gives foods a finer texture and prolongs shelf life
It also removes important nutrients, such as B vitamins, fibre, and iron
Refined CHO
http://i.ehow.com/images/GlobalPhoto/Articles/2263050/37510-main_Full.jpg
http://sparkyboi.files.wordpress.com/2008/06/white-rice.jpg
CHO rich foods with a low nutrient to energy ratio – may be simple or complex CHO.
CHO rich foods which are also high in fat and/or sugar
jam, soft drinks and cordials, pastries, biscuits, sweets and chocolates
Refined CHO Rich Foods
CHO rich foods with a high nutrient to energy ratio – may be simple or complex CHO.
Wholesome CHO rich foods should be No1 choice
Fruit, milk, scones, pasta, rice, starchy vege's, breakfast cereals, legumes and whole meal/ whole grain breads
Wholesome CHO Rich Foods
Added sugars are a more concentrated form of CHO and calories
Naturally occurring sugars in fruit and complex CHO in grains and vege’s are diluted with fibre and water, making them bulkier….. I.e. they fill you up with out the extra calories
Added sugars are digested and absorbed more quickly◦ Rapid increase in blood sugar leading to a rapid
surge of insulin causing a rapid drop in blood sugar◦ Leaving you tired, hungry and craving more sugar
Added Sugars
Simple CHO (Sugar) Complex CHO (starch)
Added sugars Refined, processed foods (low fibre)
White table sugar White rice
Molasses White pasta
Brown Sugar Instant potatoes and French fries
Honey
Concentrated fruit juice sweeteners
Naturally occurring sugars Whole foods (high fibre)
Fruit sugar (fructose) Whole wheat or grain breads and cereals
Milk sugar (lactose) Oats, brown and wild rice, whole wheat pasta, beans, peas, whole vegetables and fruits
Simple and Complex CHO
A whole grain has four parts◦ Germ◦ Endosperm◦ Bran◦ Husk
• Refinement is the process that removes everything but the endosperm (leaving the white nutrient poor flour)
• Enrichment is the process that adds back 5 nutrients to the white refined flour• Iron, thiamin, riboflavin, niacin and folic acid• All the other nutrients from the whole grains
(magnesium, zinc, Vit B6, chromium, Vit E and fibre) are still lost
Whole grains
Bran: outer layer◦ Fiber, antioxidants, minerals, b vit’s
Germ:◦ Vitamins, antioidants, folate,
Endosperm: Inside◦ Starchy carbohydrate
Refinement is the process leaving only the endosperm
Whole grains versus refined CHO
Technically none
◦ The body has the ability to convert some Protein and Fat into CHO
◦ 45-65% total energy intake is CHO
◦ For a 2000kcal diet, approx 300 grams of CHO (60% daily caloric intake)
How Much CHO Is Needed?
Simple refined sugars should be limited to ~10% of energy
Sometimes quantity is expressed as g/kg body weight◦ 7-10 (Maughan & Burke, 2002)
How Much CHO Is Needed?
SERVINGS PER PACKAGE: 8.5 (15 SLICES AND 2 CRUSTS)SERVING SIZE: 88g (2 slices) Contents Quantity Per Serving Quantity Per 100g
ENERGY 800kJ 910kJ
PROTEIN 7.9g 9.0g
FAT, TOTAL 0.9g 1.0g
-SATURATED 0.2g 0.3g
CARBOHYDRATE 35.6g 40.4g
-SUGARS 2.8g 3.2g
DIETARY FIBRE 3.6g 4.1g
SODIUM 375mg 425mg
# All specified values are averages
Vogel's original toast
NUTRITION INFORMATION (AVERAGE)
Serving Size - 30g (2 biscuits)
Per Serving Per 100g
Energy (kJ) 444 1480
(Cal) 106 354
Protein (g) 3.6 12
Fat, total (g) 0.4 1.3
- Saturated fat (g) 0.1 0.3
Carbohydrate, total (g) 20 67
- Sugars (g) 0.8 2.8
Dietary Fibre (g) 3.3 11
Sodium (mg) 84 280
Weet-Bix
http://www.sanitarium.co.nz/our-foods/breakfast/weet-bix.aspx
Per 500ml Per 100ml
Energy 300cal 60cal
1250kJ 250kJ
Total Carbohydrate Sugars
75g 15g
50g 10g
Protein 0g 0g
Fat 0g 0g
Horleys carbo cola
http://www.horleys.com/ViewProduct.aspx?id=19
Per ServingMedium potato (173 g)
Per 1oog
Energy calories
161 93cal
CHO 37 21g
FAT 0g
PRO 4 39
Baked potato (skin on)
High GI CHO gives greater glycogen storage than low GI CHO
Solid and liquid foods are equally effective
Types of CHO
‘the effect a food has upon the rate and amount of increase in the blood glucose level’ (Williams, 2005,p120)
A food’s index rating does not only depend on its grouping as simple (monosaccharide's and disaccharides) or complex (starch and fibre) (McArdle, Katch & Katch, 2001)
Glycemic index (GI)
Physical form (coarse or fine) Serving mode (raw or cooked) Individual response High fibre foods generally have low GI Fructose has a low GI
◦ Fruits high in fructose
Factors that influence G.I
Put these in order
Random order
High to low Whole meal bread
Potato chips
Glucose Carrot
Apple
Glucose
Carrot
Whole meal bread
Potato chips
Apple
100
92
72
51
39
Glycemic Index of some common foodsHigh Glycemic (> 85) Medium Glycemic(60-85) Low Glycemic (< 60)
Bagel All Bran cereal Apple
Bread (White & Meal) Baked Beans Applesauce
Candy Banana Cherries
Cornflakes Corn Chickpeas
Corn syrup Grapes Dates
Crackers Oatmeal Figs
Honey Orange Juice Fructose
Potatoes Pasta Ice-cream
Raisins Potato Chips Kidney beans
Fizzy Drinks Rice Lentils
Sports Drinks Rice, Long Grain Skim milk
Creamed Rice Spaghetti Peaches
Jelly Beans Wholegrain bread Plums
Instant rice Yams Yogurt
Williams p.121
Individual foods are often not consumed independently
Often consumed in combination with protein and fat. Such as in a hamburger, or a sandwich, which reduces the glycemic effect of the CHO. The term glycemic load can be used to quantify the glycemic response
Glycemic load also takes in to account portion size◦ a high GI food eaten in smaller portions is thought to have
the same blood glucose response as a low GI food consumed in larger quantities.
Glycemic load
“the effect a good has upon the rate and amount of increase in the blood glucose level” (Williams, 2005,p120)
http://www.glycemicindex.com/
Glycemic index
The means by which CHO is carried in the blood
Normal blood glucose levels range between 80-100mg/ml or 80-120mg/ml dependant on text
A rise in blood glucose stimulates the pancreas to secrete insulin in to the blood
Insulin is a hormone that stimulates and facilitates the uptake and utilization of glucose (mainly by muscle and adipose tissue)
Blood glucose (blood sugar)
Williams, 2005
A hormone secreted by the pancreas that is involved in CHO metabolism
Insulin response◦ Blood insulin rises following ingestion of sugar◦ Insulin causes sugar to be taken up by the
muscles and fat cells◦ Possibly creating a reactive hypoglycemia
◦ High insulin levels are a risk factor for heart disease and diabetes
Insulin
Williams, 2005
Fates of blood glucosePage 121, Williams (2005)
Alcohol
http://www.portlandopenbeerclub.com/beer.jpg http://www.monkseaton.org.uk/
adultlearning/PublishingImages/wine_tasting1.jpg
Ethanol Clear, colourless liquid Derived from fermentation of sugars in
fruits, vegetables and grains Alcohol contains about 7kcal per gram “proof” is a measure of alcohol content
◦ Twice that of the percentage◦ I.e. 80-proof whiskey: 40% alcohol
Williams, 2005
Beverage CHO (g) Total cal
Beer 13 150
Table wine 4 100
Ingested CHO converted to blood glucose◦ Used for energy, stored in the liver and muscle as
glycogen, or excess CHO converted to fat
Major function is to supply energy
3 sources of CHO stores in the body are; liver and muscle glycogen and blood glucose
Recap key points