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Although the term "sugar addiction" often appears in
magazines and on television, scientists had not demonstrated that
such a thing as sugar dependency really exist. Researchers studied
rats that were induced to binge on sugar and found that they exhibited
telltale signs of withdrawal, including "the shakes" and
changes in brain chemistry, when the effects of the sweets were
blocked. These signs are similar to those produced by drug withdrawal.
Sugar triggers production of the brain's natural opioids. That
is a key to the addiction process. The brain is getting addicted
to its own opioids as it would to morphine or heroin. Drugs give
a bigger effect, but it is essentially the same process.
The greatest value of the research is that it provides an animal
model of sugar dependency, allowing scientists to probe more deeply
the connections between food cravings and brain physiology.
In their experiments, the researchers started rats on a pattern
of bingeing by withholding food for 12 hours when the rats were
sleeping and through breakfast time, then giving them nutritionally
balanced food plus sugar water. The animals gradually increased
their daily sugar intake until it doubled, consuming most of it
in the first hour it was available.
When the researchers suddenly removed the sugar portion of the
rats' diet, the animals exhibited teeth chattering, a common sign
of withdrawal. For some animals, the researchers removed the sugar
and also administered a dose of a drug that blocks the opioid receptors
in the brain. In addition to teeth chattering, those animals showed
anxiety and a reversal in the usual balance of neurochemicals in
the brain's motivation system.
Animals that binged on normal food with no sugar and received the
opioid blocker did not show these withdrawal signs. Animals that
were given a steady diet of food and sugar water without binging
also did not show signs of withdrawal.
Obesity
Research June 2002;10(6):478-88
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