Effect of feeding frequency on glucose and insulin metabolism and substrate partitioning in impaired glucose tolerant (IGT) men

The recent escalating obesity trend in man is due to an imbalance between
energy intake and energy expenditure. Energy intake is influenced by the effect
of food*s energy density, total energy content and feeding frequency and the
extent to which these alter satiety. Of these factors, feeding frequency has
received least attention. Epidemiological evidence in human subjects indicates
increasing trends in recent years of dietary snacking and increased meal
frequency and such studies show positive relationships between snacking and
increased energy intake and BMI, illustrating the potential importance of
investigating feeding frequency.

The presently proposed study aims to investigate how different feeding
frequencies lead to differences in glucose and insulin metabolism in impaired
glucose tolerant (IGT) men.

This study is a randomized, controlled crossover study with 1 group of 14
healthy male volunteers. Subjects are exposed to two different diets. To have a
same baseline condition before each diet, subjects have to standardize the diet
and activity over the 3 days before the tests. Therefore food-intake and
activity diaries have to be filled out before the first test day and repeated
exactly similar before other test days (see attachments for food-intake and
activity diaries). At arrival, the Continuous Glucose Monitoring System (CGMS)
will be inserted in the peri-umbilical region of the subject and subjects enter
the respiration chamber at 20.00 h and leave the chamber 36 hours later at
8.00h after a muscle biopsy was taken. The first twelve hours are to accustom
to the respiration chamber. Then, energy expenditure measurements are made
during 24 hours. During the test satiety questionnaires have to be filled out.
Also bloodsamples will be taken at baseline and after a half hour and then
hourly.

1. high feeding frequency (14 meals a day)
2. low feeding frequency (3 meals a day))

Risks as the result of participation in this experiment are minimal.
Venapunctures can occasionally cause a local haematoma or bruise to occur. Some
participants report some pain during venapuncture. Insertion of the CGMS could
induce some pain, because this system will be placed by means of a needle. The
needle will be removed after insertion of this system. however no discomfort is
expected from carrying this device. Previous studies have shown that wearing
the CGMS does not hinder the subject in his normal functioning.
Due to the local anesthesia, the biopsy is as good as painless. Some
participants however, do report a sense of pressing pain during biopsy taking.
This tension is very comparable to pain that occurs upon bumping against a
table edge. Occasionally the procedure might cause a local haematoma or bruise.
To minimize this risk, after taking the muscle biopsy, the wound will be
covered with a sterile water-resistant plaster and the leg will be taped with
an elastic adhesive compression bandage. The place of incision will leave a
small scar. To promote good wound healing, the incision will be sealed with
sterile steristrips.
Also participants will be asked if they are claustrophobic, because this could
become a problem when they are staying in the respiration chamber and will be
excluded if no solution can be found.
No harm from the dietary intervention is to be expected. All diets used during
this study are purchases in the local supermarket and used before indicated
expiring dates. During the test days meals will be prepared in the kitchen of
the department of Human Biology which is solely dedicated for preparing of food
for human use.