Imagine a typical
lunchtime meal – say, chicken and vegetables with a glass of water.
If you eat
the food and drink the water, you will feel full for a couple of
hours before hunger kicks in. But if you blend the food with the
water – to make soup – you will stay hunger-free for much longer,
and less likely to snack through the afternoon.
How can blending
the food into soup make such a difference? The answer lies in the
stomach. Scientists have used ultrasound and MRI scans of people’s
stomachs to investigate what happens after eating solid-food-plus-water
meals compared with the same food made into soup.
After you eat
a meal, the pyloric sphincter valve at the bottom of your stomach
holds food back so that the digestive juices can get to work.
passes straight through the sphincter to your intestines, so drinking
water does not contribute to "filling you up".
When you eat
the same meal as a soup, the whole mixture remains in the stomach,
because the water and food are blended together. The scientists’
scans confirm that the stomach stays fuller for longer, staving
off those hunger pangs.
The key to
this low-tech weapon against hunger is a hormone called ghrelin.
It is one of the major players in the body’s appetite system.
as recently as 1999, ghrelin is released by specialised cells in
the stomach wall.
produce a constant stream of ghrelin whenever the stomach is empty.
The ghrelin travels via the blood stream to the brain’s appetite
centre, an organ called the hypothalamus. As a result, the hypothalamus
screams "You are hungry – find food."
the stomach wall is stretched – when the stomach is full – the cells
stop producing ghrelin, and the hypothalamus responds accordingly,
turning off the appetite signal. The longer the stomach remains
full, the longer you feel satisfied and the less you are likely