Indice GlicemicoIndice Glicemico

WHAT IS “GI” ?

Not all carbohydrates are equal! Glycemic Index (GI)

is a useful tool to help us choose the right type / quality

of carbohydrates that will positively influence our

health.

GI is a ranking of carbohydrate foods from 0 to 100 GI is a ranking of carbohydrate foods from 0 to 100

based on how quickly they raise our blood sugar levels.

Developed By: Glycemic Index Research Unit

Glycemic Index• = a quantitative ranking of foods based on

their postprandial blood glucose response (above fasting glucose) compared to a reference foodreference food

• The reference food is either:– White bread (50 g available cabohydrate)– Glucose (50 g)

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What Does the Glycemic Index Value Mean?

� The glycemic index (GI) is expressed as a ratio comparing the

blood glucose increase caused by a test food to that of a

reference food (usually glucose [G], historically white bread [WB])

for

2 hours following ingestion:

Area Under the Curve for Test Food

× 100 = GI

� Conversion for different reference foods: GIG × 1.4 = GIWB

– The GIG for carrots (mean of 4 studies) = 47

– The GIWB for carrots (mean of 4 studies) = 68

5

Area Under the Curve for Reference Food× 100 = GI

Atkinson FS, et al. Diabetes Care. 2008;31(12):2281-2283.

Blood Glucose Response to High vs Low Glycemic Index Foods

� Data on blood glucose responses to bread and lentils in a subject

without diabetes

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6

5

Blo

od G

luco

se, m

mol

/L

Lentils

Bread

6

Wolever TM, et al. Am J Clin Nutr. 1991;54(5):846-854.

4

3

2

1

0

Blo

od G

luco

se, m

mol

/L

0 15 30 45 60 75 90 105 120Time, minutes

Blood Glucose Response to Foods With Varying Glycemic Index

Blood Glucose Areas Under the Curve for the 4 Meals (mmol•min/L)

7

6.5

6

5.5

5

Blo

od G

luco

se, m

mol

/L

White breadCandy barModerate-carbohydrate energy barHigh-carbohydrate energy bar

Hertzler SR. J Am Diet Assoc. 2000;100(1):97-100.

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0 15 30 45 60 75 90 105 120Time, minutes

White Bread166.1 ± 31.7

Candy Bar161.6 ± 19.4

Moderate-Carbohydrate Energy Bar91.9 ± 22.6

High-Carbohydrate Energy Bar125.0 ± 21.6

5

4.5

4

3.5

Blo

od G

luco

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mol

/L

GI CLASSIFICATION

Developed By: Glycemic Index Research Unit

L’indice glicemico

ALIMENTO IG ALIMENTO IG Pane bianco 100 Arachidi 19 Pane integrale 96 Soia in scatola 20 Riso brillato 117 Patate novelle 80 Riso integrale 81 Patate al forno 135

Orzo perlato 32 Patate bollite 105 Orzo perlato 32 Patate bollite 105 Spaghetti 52 Patate dolci 70 Maccheroni 68 Mele 52

Pasta all’uovo 64 Pere 47 Lenticchie rosse secche 43 Arance 59 Fagioli bianchi secchi 48 Banane mature 90 Fagioli cannellini secchi 54 Ciliegie 32 Fagioli borlotti secchi 60 Pesche 40 Ceci secchi 17 Glucosio 131 Fave con la buccia secc 37 Fruttosio 35 Piselli surgelati 74 Latte intero 49

WHAT INCREASES THE GI OF FOODS

Read The Food Labels And Choose The Food Products Carefully!

Developed By: Glycemic Index Research Unit

WHAT REDUCES THE GI OF FOODS

You need not exclude all high GI foods from your diet.Instead include a greater proportion of low GI foods.

Developed By: Glycemic Index Research Unit

Application of GI• Diabetes: the GI helps in control of

blood glucose and insulin responses • Sports performance: Different GI foods

more effectively replenish glycogen stores after exercise: High GI foods stores after exercise: High GI foods replenish glycogen better than low GI foods

• Appetite Research: Low GI foods produce greater satiety than high GI foods

Glycemic index (GI)Glycemic index (GI)

• Frequent and high changes in blood glucose are thought to be risk factors for diabetes

AUC

AUCref

AUC

Jenkins et al. 1981. Am J Clin Nutr. 34: 362-6.

Serving size Glycemic indexCoke 250 mL 63

Mashed potato 1 cup 74White bread 1 slice 70Sugar, table 1 tsp 68

Carrots 0.5 cup 47Pasta 1 cup 42

Glycemic Response

White BreadSpaghetti

50

25

0

-25∆ P

lasm

a G

luco

se, m

g/dL

Insulinemic ResponseTime, min

0 30 60 90 120 150 180

Insulinemic Response

Time, min0 30 60 90 120 150 180

50g CHOEur J Clin Nutr, 1991, 45, 489-99,JAMA, 2002, 287, 2414-23

Glycemic loadGlycemic load

• Glycemic index does not take into account total carbohydrate

Glycemic load:

GI * carb / 100GI * carb / 100

Salmeron et al. 1997. Diabetes care. 20: 545-50.

Serving size Glycemic index Carbohydate (g) Glycemic loadCoke 250mL 63 26 16

Mashed potato 1 cup 74 20 15White bread 1 slice 70 14 10Sugar, table 1 tsp 68 10 7

Carrots 0.5 cup 47 6 3Pasta 1 cup 42 47 20

GL ≤ 10 = low GL ≥ 20 = high

Glycemic Load (GL): What does it mean?

Glycemic load measures the degree of

glycemic response and insulin demand produced

by a specific amount of a specific food.

Glycemic load reflects both the quality and Glycemic load reflects both the quality and

the quantity of dietary carbohydrates.

GL = GI/100 x CHO (grams) per serving

Example: GL of an apple = 40/100 x 15g = 6g

What Is the Glycemic Load?

� The glycemic load (GL) takes into account the amount of

carbohydrate (CHO) in a common serving in addition to its

glycemic index (GI):

� Example:

GL = (GI of CHO × grams of CHO per serving) ÷ 100

– Carrots (peeled, boiled) have a GI of 47 and 5 g CHO per serving

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The GLG of carrots is: (47 × 5) ÷ 100 = 2.4

Abbreviations: CHO, carbohydrate; GL, glycemic load; GI, glycemic index.

Atkinson FS, et al. Diabetes Care. 2008;31(12):2281-2283.

Glycemic Load (GL): Ranking

Individual food portion:

Low 0-10

Moderate 11-19

High 20+

Whole day:

Low < 80

Moderate 100

High > 120

GI vs. GL

Glycemic Index: ranks carbohydrates based on

their immediate blood glucose

response.

GI = glycemic quality

Glycemic Load: helps predict blood glucose

response to specific amount of

specific carbohydrate food.

GL = glycemicquality

quantity

Glycemic Index and Load Standards for Foods

� GI (based on glucose reference)

– Low GI 0 to 55

– Intermediate GI 56 to 69

– High GI ≥ 70

� GL (based on glucose reference)

– Low GL 0 to 10

– Intermediate GL 11 to 19– Intermediate GL 11 to 19

– High GL ≥ 20

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Abbreviations: GI, glycemic index; GL, glycemic load.

Brand-Miller J, et al. The New Glucose Revolution: The Authoritative Guide to the Glycemic Index-The Dietary Solution for Lifelong Health. 3rd ed. New York, NY:

Marlowe and Co.; 2006.

Brand-Miller JC, et al. Am J Clin Nutr. 2003;77(4):993-995.

Caution!

Do not focus exclusively on achieving a

low glycemic load diet with all low

glycemic index food choices.

Result could be: high fatResult could be: high fat

low carbohydrate

low fiber

calorically dense

Instead…

A Better Idea

Aim for a well-balanced diet that includes low

glycemic index carbohydrates. Use glycemic

load as a guide for controlling portions.

Hint: Low GI CHOs allow for larger portions, while regulating the GL.High GI CHOs require smaller portions to regulate the GL.

Usefulness of Glycemic Index and Glycemic Load

� Diabetes control with low GI foods and diets– Supplement to exchange lists

– Category B evidence according to ADA

– Positive meta-analysis

• Brand-Miller J, et al. Diabetes Care. 2003;26:2261-2267

� Sports nutrition (pre- and postexercise)1

– Low-GI foods before endurance exercise (shaky evidence)

– High-GI foods after exercise (strong evidence of benefit)– High-GI foods after exercise (strong evidence of benefit)

� Reduced CVD risk with low GI/low GL2

– Mostly epidemiologic evidence

� Weight control with low GI/low GL3

� Lowered risk of several types of cancer with low GI/low GL4,5

– Mostly epidemiologic evidence

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Abbreviations: ADA; American Diabetes Association; CVD, cardiovascular disease; GI, glycemic index; GL, glycemic load.

1. Burke LM, et al. Int J Sport Nutr. 1998;8(4):401-415.

2. Brand-Miller J, et al. J Am Coll Nutr. 2009;28(suppl):446S-449S.

3. Ludwig DS. Lipids. 2003;38(2):117-121.

4. Freedland SJ, et al. Curr Opin Urol. 2009;19(3):263-267.

5. Gnagnarella P, et al. Am J Clin Nutr. 2008 ;87(6):1793-1801.

Use Of GI In Sports Nutrition

• Before Exercise: A low-GL CHO should be eaten, particularly before prolonged exercise, to promote sustained CHO availabilityavailability

• During Exercise: Moderate to High-GL CHO foods or drinks are most appropriate

• After Exercise: High-GL CHO for glycogen resynthesis