Fructose consumption spurs sudden weight gain

Although previous studies have shown that being
leptin resistant can lead to rapid weight gain on a high-fat,
high-calorie diet, this is the first study to link it with high
fructose consumption.

The study also showed for the first time
that leptin resistance can develop silently, with little indication
that it is happening.

The study was carried out by Alexandra
Shapiro, Wei Mu, Carlos Roncal, Kit-Yan Cheng, Richard J. Johnson and
Philip J. Scarpace, all from University of Florida College of Medicine
in Gainesville.

Obesity is a growing problem worldwide and
fructose has been suspected of playing a role. Fructose is the sugar
found in fruit, but it’s not the normal consumption of fruit that is
the problem.

Table sugar and high-fructose corn syrup are
about 50 percent fructose and these ingredients have become
increasingly common in many foods and beverages. With sugar and
high-fructose corn syrup being added to many foods, people now eat much
more fructose than ever before.

Florida researchers hypothesised
that a high-fructose diet could lead to leptin resistance, which in
turn could lead to exacerbated weight gain in the face of a high-fat,
high-calorie diet, a typical diet in industrialised countries, said a
release of University of Florida.

To test their hypothesis,
the research team performed a study with two groups of rats. They fed
both groups the same diet, with one important exception: one group
consumed a lot of fructose while the other received no fructose.

During
these six months, there were no differences in food intake, body
weight, and body fat between rats on the high-fructose and the rats on
the fructose-free diets.

Besides, there was no difference
between the two groups in the levels of leptin, glucose, cholesterol or
insulin found in their blood. There was only one difference at the end
of the six months: The rats on the high-fructose diet had higher levels
of triglycerides in their blood.

The first six months of the
study showed that leptin resistance can develop silently. “Usually,
leptin resistance is associated with obesity, but in this case, leptin
resistance developed without obesity,” Shapiro said. “This was very
surprising.”

Animals exposed to the high-fructose diet, the
leptin resistant rats, ate more and gained much more weight and fat
than the leptin responsive animals on the fructose-free diet.