FLASHBACK: This is how the food industry makes Americans fat and hungry

Inundated with foods and drinks that contain high-fructose corn syrup, the US food industry is largely at fault for driving up obesity rates, since the cheap sweetener inhibits the brain from regulating the body's appetite.

From soda to ketchup, many processed foods and beverages contain fructose, which affects the region of the brain that regulates appetite, according to a study by the Scientific American, which was published in the Journal of the American Medical Association. Researchers measured the hypothalamus, which regulates hunger-related signals, of 20 healthy adult volunteers to study their responses to consuming sweetened beverages.

Upon receiving a 300-calorie drink sweetened with 75 grams of fructose, the volunteers had a more active hypothalamus and showed greater signs of hunger. When the volunteers received a similar drink that was instead sweetened using glucose, their hypothalamus was less active and the participants showed signs of fullness.

Drinking glucose "turns off or suppresses the activity of areas of the brain that are critical for reward and desire for food," Yale University endocrinologist Dr. Robert Sherwin, who was involved with the study, told the Associated Press.

With fructose, "we don't see those changes," he added. "As a result, the desire to eat continues - it isn't turned off."

Glucose and fructose are metabolized differently, and the excessive use of fructose in American food staples is taking its toll. Even table sugar, which some incorrectly believe is made up solely of glucose, is half fructose. And the US uses lots of it. Researchers at the University of Southern California and the University of Oxford found that out of 42 countries studied, the US has the highest per-capita consumption of high-fructose corn syrup.

The US also has the highest obesity rate in the world, with more than one-third of adults (35.7 percent) being classified as 'obese' by the Centers for Disease Control and Prevention.

"This increased intake of added sugar containing fructose over the past several decades has coincided with the rise in obesity in the population, and there is strong evidence from animal studies that this increased intake of fructose is playing a role in this phenomenon," said Dr. Jonathan Purnell of the Oregon Health and Science University in Portland, who co-authored an editorial that accompanied the study.