The primary aim of the present study was to expand the glycaemic index (GI) database by determining the GI and insulin index values of thirty-nine foods containing sugars in healthy adults. The second aim was to examine the hypothesis that glycaemic and insulin responses to foods which contain added sugar(@ are higher than responses to foods containing naturally-occumng sugars. Eight healthy subjects drswn from a pool of eighteen consumed 50 g carbohydrate portions (except 25 g carbohydrate portions for fruits) of the test foods. The GI and insulin index were determined according to standardized methodology and expressed on a scale on which glucose = 100. The median GI and insulin index values of all foods tested were 56 (range 14 to 80) and 56 (range 24 to 124) respectively. The median GI of the foods containing added sugars was similar to that of foods containing naturally-occurring sugars (58 Y.53 respectively, P = 0.08). Likewise, the median insulin index of the foods containing added sugars was not significantly different from that of foods Containing naturally-occurring sugars (61 v. 56 respectively, P = 0.16). There was no evidence of 'rebound hypoglycaemia' or excessive insulin secretion relative to the glucose response. We conclude that most foods containing sugars do not have a high GI. In addition, there is often no difference in responses between foods containing added sugars and those containing naturally-wcurring sugars. 1988). Many diabetes associations have accepted the principle of the GI, but they recommend that more research is needed for general application (Brand Miller, 1994). Apart from some fruits, most of the foods tested have been high in starch rather than sugars.Sugars are an important component of diets in developed countries, providing about 20 % of the total energy consumed and nearly half the total carbohydrate (Glinsmann et al. 1986;Baghurst et al. 1989; Department of Health, 1989). Approximately half the sugar is derived from added sugars and the other half from naturally-occurring sources, such as fruit and milk.The glycaemic and insulin responses to sugars are also relevant to sports performance (Thomas et af. 1991), satiety (Holt et af. 1992) and serotonin-related phenomena, such as sleepiness (Lyons & Truswell, 1988). The GI of foods containing sugars should also be considered in the emergency treatment of hypoglycaemia. The common assumption that foods containing sugars will produce a more rapid glycaemic response than starchy foods has little scientific basis.

Objective: To investigate in children with cystic fibrosis (CF) and children without CF: (1) the test -retest reproducibility of a 20 min resting energy expenditure (REE) measurement; and (2) the long-term reproducibility of REE measurements in children with CF using longitudinal data. Design: Cross-sectional study and longitudinal cohort. Setting: A tertiary referral paediatric hospital. Subjects: A total of 31 (11 male, 20 female) children (aged 12.8 AE 3.6 y) with CF and 32 (14 male, 18 female) healthy children without CF (aged 12.2AE 2.3 y) were enrolled in the short-term reproducibility study. Long-term REE measurement reproducibility was assessed in another 14 children (5 male, 9 female) with CF, comparing their initial REE measurement with a subsequent measurement 1 -2 y later. Methods: All children had measurements of height, weight, skinfold thickness and indirect calorimetry. Results: There was no statistically significant difference in REE between repeated measurements in children with CF (mean AE s.d., 6240AE 1280 and 6220 AE 1315 kJ=24 h) and in the children without CF (6040 AE 956 and 6015 AE 943 kJ=24 h). For the children with CF, the intraclass correlation coefficient was 0.99 and for children without CF the intraclass correlation coefficient was 0.97. The measurement errors were 119 and 177 kJ, respectively. Approximately 80% of the variation in REE in the CF group and 70% in the group without CF was explained by fat-free mass (FFM). Analysis of the longitudinal CF data show there was no difference in REE between a child's first measurement (5140 AE 1140 kJ) and their subsequent measurement (5460 AE 1190 kJ), after adjustment for changes in body size between the measurements. Conclusion: This study has demonstrated that a short-term 20 min REE measurement is reproducible and therefore valid in children with CF and children without CF. These results also indicate that in children with CF, long-term REE measurements are reproducible.

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