High-fructose corn syrup linked to weight gain

Posted by Nicole Eckersley on 25th March 2010

A research team from Princeton University has found that rats who consume high-fructose corn syrup (HCFS), the US’s most common sweetener, gain significantly more weight than rats who consume normal table sugar, despite consuming the same number of calories.

“Some people have claimed that high-fructose corn syrup is no different than other sweeteners when it comes to weight gain and obesity, but our results make it clear that this just isn’t true, at least under the conditions of our tests,” said psychology professor Bart Hoebel, who specializes in the neuroscience of appetite, weight and sugar addiction.

“When rats are drinking high-fructose corn syrup at levels well below those in soda pop, they’re becoming obese – every single one, across the board. Even when rats are fed a high-fat diet, you don’t see this; they don’t all gain extra weight.”

The study could shed light on America’s recent obesity epidemic, with vast amounts of HCFS used in the US food industry – 55% of all sweeteners. The introduction of HCFS  in 1970 coincided with the beginning of the upward weight trend; today, around a third of American adults are defined as obese by the Centre for Disease Control.  However, HCFS cannot be entirely to blame, with other countries, Australia included, following the obesity trend without the HCFS consumption.

The study examined weight gain, body fat and triglycerides in rats, whose water was sweetened to soft-drink levels with sugar, or half-soft-drink levels with HCFS, over six months.  The rats showed signs of a condition called metabolic syndrome, including weight gain and fat deposits around the belly. Male rats were particularly affected, gaining 48% more weight than those eating a normal diet.  In human terms, this would be equivalent to an 80kg man gaining 38kg.

The American Corn Refiners Association hit back at the Princeton results.  “Consumers should not be misled by exaggerated studies that feed astronomical amounts of one ingredient to the study subjects, in this case rats. The medical community has long dismissed results from rat dietary studies as being inapplicable to human beings,” stated Audrae Erickson, president, Corn Refiners Association.

HCFS is rarely used in Australia, with cane sugar being cheaper and more readily available.  Corn is the US’s largest crop, accounting for a quarter of harvested grains, and HCFS generates around $4.5 billion in annual profits.