Ten pairs of normal men were overfed by 5 MJ/d for 21 d with either a carbohydrate-rich or a fat-rich diet (C- and F-group). The two subjects in each pair were requested to follow each other throughout the day to ensure similar physical activity and were otherwise allowed to maintain normal daily life. The increase in body weight, fat free mass and fat mass showed great variation, the mean increases being 1·5 kg, 0·6 kg and 0·9 kg respectively. No significant differences between the C- and F-group were observed. Heat production during sleep did not change during overfeeding. The RQ during sleep was 0·86 and 0·78 in the C- and F-group respectively. The accumulated faecal loss of energy, DM, carbohydrate and protein was significantly higher in the C- compared with the F-group (30, 44, 69 and 51 % higher respectively), whereas the fat loss was the same in the two groups. N balance was not different between the C- and F-group and was positive. Fractional contribution from hepatic de novo lipogenesis, as measured by mass isotopomer distribution analysis after administration of [1-13C]acetate, was 0·20 and 0·03 in the C-group and the F-group respectively. Absolute hepatic de novo lipogenesis in the C-group was on average 211 g per 21 d. Whole-body de novo lipogenesis, as obtained by the difference between fat mass increase and dietary fat available for storage, was positive in six of the ten subjects in the C-group (mean 332 (SEM 191) g per 21 d). The change in plasma leptin concentration was positively correlated with the change in fat mass. Thus, fat storage during overfeeding of isoenergetic amounts of diets rich in carbohydrate or in fat was not significantly different, and carbohydrates seemed to be converted to fat by both hepatic and extrahepatic lipogenesis.

Objective: To test the hypothesis that diets with high glycaemic index (GI) and glycaemic load (GL) increase the risk of heart disease. Design: Overall GI and GL were assessed from 7 d diet records or diet history interviews. Setting: Information on hospitalization and death due to CVD and CHD was obtained from the National Register of Cause of Death and the National Register of Patients. Subjects: In total 3959 adult Danes were -depending on time of entry -followed for 6-25 years until 31 December 1999. Results: Overall GI was inversely associated with heart disease in men. The hazard ratios (95 % CI) for the 10th and 90th GI percentiles compared with the median were 1?38 (1?13, 1?68) and 0?90 (0?76, 1?07) for CVD morbidity, 1?45 (1?05, 1?99) and 0?81 (0?62, 1?06) for CVD mortality, and 1?31 (0?97, 1?76) and 0?65 (0?51, 0?84) for CHD morbidity. In male subjects GL was not associated with either outcome. In women no clear association between overall GI and heart disease was found, whereas positive non-linear associations were found for GL: at very high levels of GL, increase in GL was associated with increasing CVD and CHD morbidity. Conclusions: In men low-GI diets were associated increased risk of heart disease and GL was not associated with heart disease. In women there was no clear association between GI and heart disease, but to some extent a positive association between GL and heart disease was observed as hypothesized.

The aim of this study was to describe dietary glycaemic index (GI) and glycaemic load (GL) values in the diets of Danish children, and to examine the associations between dietary GI, GL and body fatness. Data were collected during 1997-8 as part of the European Youth Heart Study. The study population comprised 485 children aged 10 years and 364 children aged 16 years from Odense County, Denmark. Dietary GI and GL were estimated using international food tables, and the associations between energy-adjusted dietary GI, GL and body fatness were analysed by multiple linear regression. The mean daily dietary GI value was 85 (SD 6·9) with a range of 62 -111. No significant differences were found between age groups and gender. The daily dietary GL was higher among boys aged 16, with a GL of 330 (SD 95) (P,0·05), compared with girls or younger boys. Dietary GL was higher among 10-year-old boys than girls (250 (SD 81) v. 230 (SD 66) P,0·05), whereas dietary GL among 16-year-old girls was 230 (SD 56). Neither dietary GI nor GL was associated with the sum of four skinfolds (SSF) among girls or among 10-year-old boys. Among 16-year-old boys, significant associations were observed between dietary GI and SSF (b ¼ 0·60, SE ¼ 0·21, P¼ 0·006), and between dietary GL and SSF (b ¼ 0·15, SE ¼ 0.06, P¼0·009). In conclusion, dietary GI and GL were positively associated with body fatness among Danish boys aged 16 years, whereas no associations were found among girls or younger boys.

In male twins with a high similarity in genetic and environmental background, the Trp64Arg polymorphism of the beta3AR gene is associated with lower fat mass, fasting insulin levels and an appropriate insulin response to glucose. Thus, heterozygosity for the Trp64Arg variant is unlikely to increase the risk of obesity, insulin resistance or type 2 diabetes.