SAO PAULO, Aug. 29 (UPI) -- A pioneering obesity and diabetes researcher has identified the rapid introduction in the 1970s of high-fructose corn syrup into the food supply -- particularly in soft drinks -- as an important factor contributing to the obesity epidemic that has swept the world in the last 30 years.
At the same time soft drink consumption has risen, consumption of calcium via milk -- which is protective against obesity -- has fallen, said Dr. George Bray, a principal investigator on the widely quoted Diabetes Prevention Program study. He is the former executive director of one of the leading research centers looking at metabolism, diabetes and obesity: Pennington Center for Biomedical Research at Louisiana State University in Baton Rouge.
At the 9th International Congress on Obesity on Friday, Bray displayed four charts from the Centers for Disease Control and Prevention and from the U.S. Department of Agriculture. The charts show from 1970 through 1990 a dramatic rise in the consumption of high fructose corn syrup as the use of cane sugar dropped. At the same time, from 1970, a chart shows a steady decline in milk consumption as soft drinks grew in popularity to eclipse per capita consumption of milk just before 1980.
High-fructose corn syrups and related sweeteners manufactured from corn starch became commercialized in the 1970s into major food additives. One food information Web site, at Oregon State University, describes the development of these sweeteners from corn starch as "one of the greatest changes in the sugar and sweetener industry over several centuries."
In 1980, soon after these substances became commercial products, Bray noted, the chart from the CDC demonstrates the beginning of a sharp rise in obesity for both men and women. From 1980 to 2000, the incidence of obesity at least doubled for men and women in the United States, while obesity had remained relatively flat for the preceding 20 years.
The changes of food consumption involving fructose-sweetened soft drinks and the drop in milk consumption "fits precisely on top of the inflexion point of the rise of obesity," Bray told a small news briefing at the congress. He said he could find no other single combination of environmental changes or food consumption habits that could be as significant to obesity as the change in drinking habits around the world.
He said fructose, sweeter than either sucrose or glucose, sidesteps certain key regulatory processes in the body. For example, it does not stimulate insulin, which is believed to be part of an important feedback pathway involved with feelings of fullness. At the same time, it stimulates formation of fat cells more than other sweeteners.
"Once inside the cell, it forms the backbone for fat molecules," he said of a key breakdown product of fructose.
Although Bray acknowledged the epidemic of obesity is the result of many factors, he added, "I believe (fructose) plays a role."
Philip James, chairman of the International Obesity Taskforce in London, said Bray's views are consistent with what is emerging from a report still being drafted on diet, nutrition and chronic disease in by the United Nations' World Health Organizaation and Food and Agriculture Organization.
Neville Rigby, director of public policy and public affairs for the task force, told UPI Bray is one of the founding fathers of the study of obesity. The statement by Bray, he said, represents one of the strongest he has heard from an elder statesmen in the field to identify fructose in soft drinks as a potentially important cause of obesity.
Bray's comments came one day after the board of the Los Angeles County school district voted unanimously to extend the ban on carbonated soft drinks to all its schools in an effort to combat childhood obesity.
News reports quote Sean McBride, a spokesman for the National Soft Drink Association as saying, "Physical education and physical activity are, by far, more important in combating obesity than banning soft drinks from students' diets. In the end, this is really about the couch and not the can."