Background:~Developing functional food products that enhance satiety, suppress appetite, and reduce subsequent voluntary food intake to a greater extent than a similar energy matched food product, may be useful to help consumers adhere to energy restricted diets and optimize successful body weight management. A range of foods and food constituents have been reported to have the potential to produce short term changes in appetite and energy intake. However, the effects of consuming foods containing such ingredients on appetite, energy intake over the longer term is unclear.~We have previously shown that consuming a mid-morning liquid preload with increasing proportion of energy derived from whey protein and addition of polydextrose reduced voluntary energy intake at a lunchtime meal compared to a liquid preload of the same energy content but lower in protein and containing no polydextrose.~Aims:~This study aims to investigate if previous findings can be replicated using solid snack bars containing whey protein and polydextrose. We will also investigate whether the daily consumption of the snack bar has an effect on energy intake, subjective appetite and metabolic and endocrine responses.~Methods:~Using a double blind, randomized cross-over design, 10 healthy lean male subjects will consume a whey protein-polydextrose bar and an iso-energetic control bar as a mid-morning, between-meal snack for 14 consecutive days. The two intervention phases will be separated by a 2-wk washout period. On the first (day 1) and the last day (day 15) of each intervention phase, subjective appetite, voluntary food intake, blood metabolite and endocrine responses to the snacks will be assessed under laboratory conditions. Additionally, participants will be asked to record free-living food intake on days 4, 8 and 12 of the intervention.
Developing functional foods that enhance satiety may be beneficial to individuals to help manage body weight.~We have previously shown that consuming a mid-morning liquid preload with increasing proportion of energy derived from whey protein and addition of polydextrose reduced voluntary energy intake at a lunchtime meal compared to a liquid preload of the same energy content but lower in protein and containing no polydextrose.~This study aims to investigate if these results can be replicated when the preload is in the form of a snack bar. We will also investigate whether the daily consumption of the snack bar has an effect on energy intake, subjective appetite and metabolic parameters compared to a control snack of the same energy but with a minimal protein content and without the addition of polydextrose.~We hypothesize that the whey protein polydextrose snack will reduce voluntary energy intake at a subsequent test meal, suppress subjective appetite ratings compared with the control snack bar.