Carbohydrate (CHO)Primary fuel

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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

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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

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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