Obese Stomachs Tell Us Diets Are Doomed
to Fail
The way the stomach detects and
tells our brains how full we are becomes damaged in obese people but does not
return to normal once they lose weight, according to new research from the
University of Adelaide.
Researchers believe this could be a key
reason why most people who lose weight on a diet eventually put that weight
back on.
In laboratory studies, University of
Adelaide PhD student Stephen Kentish investigated the impact of a high-fat diet
on the gut's ability to signal fullness, and whether those changes revert back
to normal by losing weight.
The results, published in the International Journal of Obesity, show that the nerves in the stomach that signal fullness to the brain appear to be desensitized after long-term consumption of a high-fat diet.
"The stomach's nerve response
does not return to normal upon return to a normal diet. This means you would
need to eat more food before you felt the same degree of fullness as a healthy
individual," says study leader Associate Professor Amanda Page from the
University's Nerve-Gut Research Laboratory.
"A hormone in the body, leptin,
known to regulate food intake, can also change the sensitivity of the nerves in
the stomach that signal fullness. In normal conditions, leptin acts to stop
food intake. However, in the stomach in high-fat diet induced obesity, leptin
further desensitizes the nerves that detect fullness.
"These two mechanisms combined
mean that obese people need to eat more to feel full, which in turn continues
their cycle of obesity."
Associate Professor Page says the
results have "very strong implications for obese people, those trying to
lose weight, and those who are trying to maintain their weight loss."
"Unfortunately, our results
show that the nerves in the stomach remain desensitized to fullness after
weight loss has been achieved," she says.
Associate Professor Page says
they're not yet sure whether this effect is permanent or just long-lasting.
"We know that only about 5% of
people on diets are able to maintain their weight loss, and that most people
who've been on a diet put all of that weight back on within two years,"
she says.
"More research is needed to
determine how long the effect lasts, and whether there is any way -- chemical
or otherwise -- to trick the stomach into resetting itself to normal."
This study has been funded by the
National Health and Medical Research Council (NHMRC).
Story Source:
The above story is based on materials provided by University of Adelaide.
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content and length. For further information, please contact the source cited
above.
Journal Reference:
1.
S J Kentish, T A O'Donnell, C L
Frisby, H Li, G A Wittert, A J Page. Altered gastric vagal
mechanosensitivity in diet-induced obesity persists on return to normal chow
and is accompanied by increased food intake. International Journal
of Obesity, 2013; DOI: 10.1038/ijo.2013.138
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University
of Adelaide (2013, September 16). Obese stomachs tell us diets are doomed to
fail. Science Daily. Retrieved September 16, 2013, from http://www.sciencedaily.com/releases/2013/09/130916103352.htm
