Comprising two experiments, the investigators assessed the metabolic, endocrine and appetite-related responses to acute (1-d, part 1) and daily mid-morning milk consumption (28-d, part 2) in adolescent males (15-18 y).

The aims of the present study were twofold. Firstly, this study sought to examine the acute (1-d) effects of mid-morning milk consumption on subsequent metabolic, endocrine and appetite-related responses relative to an isoenergetic and isovolumetric serving of fruit-juice (part 1). Considering the putative mechanisms of milk consumption on appetite, feeding behavior and metabolism no studies are available that have explored the impact of daily milk or dairy food consumption on the above mentioned constructs in children and adolescents. This study therefore also aimed to compare the effect of daily (28-d) mid-morning milk or fruit-juice consumption on the above mentioned constructs (part 2).

Eleven adolescents participated in part 1 of this study and completed two trials (milk or fruit-juice mid-morning snack) in a randomized crossover design. For part 2, a parallel design with two intervention groups was employed. Participants were randomly allocated to groups, and received either a milk (n = 10) or an isocaloric and isovolumetric fruit-juice (n = 9) mid-morning snack for 28-d. On laboratory visits (for both part 1 and 2) participants remained at rest for 180 min. During this time, circulating concentrations of GLP-17-36, glucagon, insulin, leptin and blood glucose were determined. Measures of energy expenditure, substrate metabolism and subjective appetite were also collected. At 180 min, a homogenous ad libitum pasta meal was provided. For the remainder of the study day, subsequent energy intake was recorded utilizing a combined weighed self-reported food record and 24-h dietary recall technique.

Inclusion Criteria:

1. Male
2. Non diabetic
3. 15-18 yrs

Exclusion Criteria:

1. Are outside of the stipulated age range (15-18 years old)
2. A diabetic
3. Hold an aversion/dislike to milk, milk based products and the test meals provided.
4. Are known to be lactose intolerant
5. Currently taking any form of medication known to affect taste, smell and appetite
6. Female