Effects of Test Meal Volume and Energy Density on Gastric Volumes and Satiety Assessed by MRI

The tone of the proximal stomach decreases on meal intake through a process of gastric accommodation, aimed at increasing the capacity of the stomach. An increased gastric volume progressively distends the stomach, and this distension has been shown to have an inverse relationship on appetite. The link is assumed to be based on activation of mechanoreceptors lying in the walls of the stomach. On activation, vagal discharges are triggered, leading to activation of hypothalamic neurons and regulation of feelings of satiety. Gasrtric emptying is also regulated by duodenal feedback mechanisms triggered by the arrival and amount of nutrients.

Based on current knowledge, a high volume test meal would be expected to produce more gastric distension and satiety over a low volume test meal, and a low energy density food would be expected to empty from the stomach faster than a high energy density food. Going on this premise, study test meal 2 would be expected to empty faster than study test meal 1. These phenomena will be investigated using non invasive Magnetic Resonance Imaging (MRI) methods. MRI can measure gastric volumes serially and non-invasively with high spatial resolution. Ultimately, the findings from this study will provide novel insights on mechanisms of gastric distension and satiety.