Oral and gastric contributions to satiety II: effects of energy content.

One of the major issues in the current food-rich environment is that many
popular foods promote a positive energy
balance, because the consumption of these foods leads to a relatively low
satiety feeling relative to their energy content.
One of the reasons for this may be their swift passage through the mouth, which
decreases sensory signalling. This
decreased sensory signalling may lead to diminished CPRs and lower sensory
satiety. Consumption of fast foods, like
caloric liquids and highly energy-dense foods may disrupt the learned
connection between sensory signals and their
physiological consequences and thereby CPRs.
In order to prevent a positive energy balance upon consumption of energy dense
food products, there is a need to know
how sensory and gastric signals and their interaction affect satiety. The
understanding of which food properties have an
impact on the oral and gastric contributions to satiety creates opportunities
to optimize food products in such a way that
satiety is maximized.

The primary objective of this study is to determine the effect of the duration
of oro-sensory exposure and/or energy content of the gastric load, on
subsequent energy intake.

The secondary objectives of the research project are to determine the effect of
short/long oro-sensory exposure combined with a gastric load low/high in
energy, on:
• subjective feelings of satiety
• gastric emptying rate

Furthermore we want to reproduce the results of one treatment (1min/800ml) of
our previous study (ABR nr 30728), to investigate whether the gastric load is
quickly emptied.

This is a randomized, cross over, single center, trial with 6 treatments:
Control: no oral exposure and no gastric load.
A: 1min oral exposure with 100kcal/500ml gastric load,
B: 8 min oral exposure with 100kcal./500ml gastric load,
C: 1 min oral exposure with 700kcal/500ml gastric load,
D: 8min oral exposure with 700kcal/500ml gastric load,
E: 1min oral exposure with 100kcal/800ml gastric load,
Subjects will have a naso-gastric tube inserted in all 6 treatments.

All subjects will receive all 6 treatments, which are described under 'study
design, in randomised order. Oral stimulation is done with modified sham
feeding (MSF) with cake, and gastric stimulation is done with a mixture of cake
and water.

30 minutes after the start of the treatment, subjects will receive a lunch
meal, and are told to eat until they are comfortably full. Ad libitum food
intake during this lunch is the primary outcome of the study

Subjects will receive one treatment per test day, and between the test days a
minimum of 5 testfree days will be scheduled.

Subjects will have 1 visit at the university and 7 visits at the hospital,
that will last for 14.5 hours all together.

The stable isotope 13-C acetate is a natural stable isotope, it makes up about
1% of all natural carbon on earth and it is present in for example corn.
Naso-gastric intubation by an experienced nurse is usually a procedure with a
low risk. Especially in healthy subjects this will not cause problems in most
of the cases. We do not expect that repeated intubation - with a wash-out
period of at least 5 days - will give a higher risk than a single intubation.
In our previous study (ABR nr 30728) no complications occurred, nor did any of
the subjects reported enduring soreness/irritation of the nose or throat.

More insight in the sensory and gastric signals and their interaction in
satiety will be present after conducting the study.
The understanding of which food properties have an impact on the oral and
gastric contributions to satiety creates
opportunities to optimize food products in such a way that satiety is
maximized.