Evaluation of acute appetite effects of crisp bread of rye : results from two cross-over studies

Abstract: Fibre rich rye products have been shown to have superior effects on appetite compared to white wheat bread through mediation of prolonged feelings of fullness, less hunger and less desire to eat. Moreover, consumption of rye products compared to white wheat bread has resulted in lower energy intake after a subsequent meal. The aim of this thesis was to evaluate the acute effects of a commercial crisp rye bread on appetite in terms of hunger, fullness and desire to eat in a four hour perspective, com-pared to a white wheat bread reference as part of a breakfast. The energy intake after an ad libitum lunch was also evaluated. The analysis is based on results from two randomised cross-over studies. Appetite was rated by visual analogue scales. In total, 20 and 21 subjects completed the studies, respec-tively. The participants were 25-53 years old and had BMI 20-26. The studies differed in terms of total energy content of the breakfasts and proportion of energy coming from the treatment product. Differences between breakfasts within the two studies were evaluated using mixed models with repeated measures appropriate for cross-over designs. Study 1 showed a lower perceived hunger and desire to eat after eating the rye break-fast, while effects on fullness were less pronounced. This is likely due to the high energy content of the breakfast or the lower proportion of test product masking the difference in effect on appetite. In Study 2 the energy content of the breakfast was lower than in Study 1 and the test product constituted a larger proportion of the breakfast. Results showed significantly high-er perceived fullness, less hunger and less desire to eat as well as a lower energy intake at lunch after eating the rye breakfast compared to the control. Rye crisp bread affects satiety through contributing to lower perceived hunger, higher perceived fullness and less desire to eat in a four hour perspective compared to a wheat reference bread. It also led to a lower energy intake after an ad libitum lunch, which may be the result of positive effects on appetite.