- Following the initial fasting blood sampling, the participant will be asked to drink approx 150 mls of Fresubin 5cal shot supplement drink over a 5 min period. The time of completion will be noted as T= 0. Further blood samples will be obtained at T=30, 60, 120, 180 and 240 minutes post-ingestion. The calorific content and proportion of macronutrients in Fresubin is very similar to that described in publications performing the OTTT (Karamanos 2001; Carstensen 2003; Mohanlal 2004).