Effect of oral exposure duration and gastric energy content on gastric emptying rate.

Rationale:

One of the major issues in the current food-rich environment is that many popular foods promote a positive energy balance, because of their low satiating efficiency per calorie. One of the reasons for this may be the quick passage through the mouth. How the mouth and the stomach influence each other with regards to gastric emptying is not fully understood.



Objective of the study:

The primary objective of this study is to investigate the effect of - short vs. long - oro-sensory exposure combined with a gastric load - low vs. high in energy -, on gastric emptying rate. As secondary outcome we want to investigate the effect of - short vs. long - oro-sensory exposure combined with a gastric load - low vs. high in energy -, on subjective feelings of satiety.



Study design:

This is a randomized, cross over, single centre, trial with 5 treatments and a wash out period of at least 5 days in between test sessions. Subjects will have a naso-gastric tube inserted in all 5 treatments.



Number of subjects:

Twenty-seven men will be enrolled. With an expected drop-out rate of approximately 10% we will end up with 24 subjects.



Study population:

Healthy men: aged 18-40 year, BMI 18.5-25 kg/m2, stable body weight, and who tolerate the treatments.



Study outcomes:

Rate of gastric emptying and subjective feelings of satiety.

Oral exposure time and energy content of the gastric load both affect subjective feelings of satiety and gastric emptying rate. It is expected that a longer oral exposure time and a higher gastric energy content would both increase subjective feelings of satiety and that a high energy content of the gastric load would delay the rate of gastric emptying.

Every subject will visit the laboratory 7 times:

1. For an information and screening meeting;

2. For a training session (where all study procedures are practised;

3. 5 testsessions with in each session:

A. VAS questionnaire: Directly before, and and 8, 15, 22, 30, 45, 60, 75 and 90 minutes after start of the treatment;

B. Breath sample collection: 2 times before start of the treatment, and 8, 15, 22, 30, 45, 60, 75 and 90 minutes after start of the treatment.

Oral and gastric stimulation:

Subjects receive (after inclusion, IC and training session) 5 treatments. 4 treatments with 2x2 design with:

1. Oral stimulation: 1 min or 8min modified sham feeding;

2. Gastric stimulation: Infusion of 500ml of liquid with 100kcal or 700kcal into the stomach with a naso-gastric tube.

Besides these 4 treatments there is a control condition: No oral stimulation but subjects are infused with a 500ml 0kcal (noncaloric) liquid.