Contents

Preface

1 Historical Introduction

1.1 The Dietary Fibre Hypothesis

1.2 Early Studies on the Glycaemic Effects of Carbohydrates

1.2.1 Studies before 1970

1.2.2 Studies after 1970

1.3 The Inception of the GI

1.4 The Development of the GI

1.5 Summary

2 Determining the GI of Foods – Methodological Considerations

2.1 Definition of the ‘Glycaemic Index’

2.1.1 Meaning of ‘glycaemic index’

2.1.2 Suggested protocol for determining the GI of foods

2.1.3 Performance of method

2.2 Effects of Variation in Methods

2.2.1 Calculation of AUC

2.2.2 Amount of ‘available carbohydrate’ in the portion tested

2.2.3 Method of blood sampling and glucose measurement

2.2.4 Type of subjects studied

2.2.5 Type of reference food

2.2.6 Time of day tests are done

2.2.7 Preparation of subjects before the test day

2.2.8 Effect of volume and type of drink consumed with the test meal

2.2.9 Time to consume test meal

2.3 Conclusions

3 The Insulin Response to Carbohydrate Foods: Critical Evaluation of the Insulinaemic Index

3.1 Insulin Sensitivity

3.1.1 Use of the term ‘insulin sensitivity’

3.1.2 Measurement of insulin sensitivity

3.1.3 Clinical utility of insulin sensitivity

3.2 Are High Postprandial Insulin Responses Harmful?

3.2.1 Hyperinsulinaemia and cardiovascular disease

3.2.2 Hyperinsulinaemia and type 2 diabetes

3.2.3 Hyperinsulinaemia and obesity

3.3 Determinants of Postprandial Insulin Responses

3.3.1 Dietary protein and acute insulin responses

3.3.2 Dietary fat and acute insulin responses

3.3.3 Dietary carbohydrate and insulin responses

3.3.4 Dietary sucrose and fructose and insulin responses

3.3.5 Relationship between glucose and insulin responses of foods

3.4 Plasma Insulin Responses of Mixed Meals and Whole Diets

3.5 Relevance of GI to Insulin Sensitivity and Related Outcomes

3.6 Variation of Plasma Glucose and Insulin

3.7 Cost of Measuring Glucose and Insulin

3.8 Clinical Utility of II

3.9 Conclusions

4 Mechanisms by which Different Carbohydrates Elicit Different Glycaemic Responses

4.1 The Monosaccharides Absorbed

4.1.1 Glucose, fructose and galactose

4.1.2 Polyols

4.2 The Amount of Carbohydrate Metabolized

4.2.1 The amount of carbohydrate consumed

4.2.2 The proportion of carbohydrate absorbed

4.3 Rate of Carbohydrate Absorption

4.3.1 Addition of viscous fibre

4.3.2 Rate of starch digestion in vitro

4.3.3 Enzyme inhibitors

4.3.4 Reducing the rate of carbohydrate consumption

4.3.5 Studies using stable isotopes

4.3.6 The euglycaemic hyperinsulinaemic clamp

4.4 Is Carbohydrate Malabsorption the Mechanism for Low-GI Foods?

4.4.1 Relation between RS measured in vitro and GI

4.4.2 Quantification of carbohydrate malabsorption in humans in vivo

4.5 Conclusions

5 Glycaemic Index: Application to Mixed Meals

5.1 Effect of Mixing Carbohydrate Foods on Glycaemic Responses

5.2 Effects of Fat on Glycaemic Responses

5.2.1 Effects of fat added to fixed amount of carbohydrate

5.2.2 Mechanism for the effect of fat on glycaemic responses

5.2.3 Isocaloric substitution of fat and carbohydrate

5.3 Effects of Protein on Glycaemic Responses

5.4 Effects of Combination of Fat and Protein on Glycaemic Responses

5.4.1 Studies in normal subjects

5.4.2 Studies in subjects with diabetes

5.4.3 Interaction of GI with added protein and/or fat

5.5 Calculation of Meal or Diet GI

5.6 Different Meals with the Same Nutrient Composition

5.6.1 What criteria should be used to determine whether the GI has utility?

5.6.2 Studies concluding against the utility of the GI

5.6.3 Statistical power

5.6.4 Qualitative approach to prediction

5.6.5 Quantitative approach to prediction

5.7 Different Meals with Different Nutrient Composition

5.8 Effect of Low-GI Diet on 24-hour Glucose Profile

5.9 Conclusions

6 Measuring Diet GI

6.1 Assessing Available Carbohydrate Intake

6.1.1 Direct observations

6.1.2 Food records or recalls

6.1.3 Food frequency questionnaires

6.2 Assigning GI Values to Foods

6.3 Distribution of Diet GI Values in Individuals

6.4 Assessment of Diet GI by FFQ

6.4.1 Population GI values assessed by FFQ

6.4.2 Validity of FFQ for assessing diet GI

6.5 Assessing Diet GI by Food Records

6.6 Conclusions

7 Glycaemic Index and Health

7.1 GI and Athletic Performance

7.2 GI and Cognitive Function

7.3 GI and Weight Management

7.3.1 Pathogenesis of obesity

7.3.2 Effect of low-carbohydrate and low-GI diets on body weight

7.3.3 Low GI and appetite regulation in adults

7.3.4 Low-GI foods and appetite regulation in children

7.3.5 GI and reduced fat storage

7.3.6 GI and efficiency of energy absorption

7.4 GI and Pregnancy

7.5 GI and Miscellaneous Conditions

7.5.1 GI and gastrointestinal tract function

7.5.2 GI and dental caries

7.6 Conclusions

8 Glycaemic Index and Disease

8.1 Diabetes

8.1.1 Dietary carbohydrates and prevention of type 1 diabetes

8.1.2 Dietary carbohydrates and prevention of type 2 diabetes

8.1.3 Effect of diet GI on glycaemic control in diabetes

8.2 Cardiovascular Disease

8.2.1 Pathogenesis of cariovascular disease

8.2.2 Effect of GI on risk for cardiovascular disease

8.2.3 Effect of GI on cardiovascular disease risk factors

8.3 Cancer

8.4 Mechanisms of Action of Low-GI Foods

8.4.1 Reduced glucose toxicity

8.4.2 Reduced plasma insulin concentration

8.4.3 Acute effects on gut hormone secretion

8.4.4 Increased colonic fermentation

8.5 Conclusions

9 Glycaemic Index vs Glycaemic Load

9.1 Definition of GL

9.2 Glycaemic Load and Acute Glycaemic Responses

9.2.1 Validity of the GL concept

9.2.2 Glycaemic glucose equivalent

9.2.3 Concluding remarks about GL and GGE

9.3 Does Low GI Equal Low Carbohydrate Beyond Acute Responses?

9.3.1 Evidence from epidemiological studies

9.3.2 Evidence from second-meal studies

9.3.3 Evidence from dietary intervention studies

9.4 Clinical Utility of GI vs GL and GGE

9.5 Conclusions

References

Index

A

B

C

D

E

F

G

H

I

L

M

N

O

P

Q

R

S

T

U

V

W