"Long before it's in the papers"
June 04, 2013


“Toxic environment” is making kids fat, study claims

Aug. 11, 2006
World Science staff

A “toxic environment” of unhealthy, addictive food is behind today’s obesity epidemic, a new study says.

Mass-produced Western foods, because they’re low in fiber, sugary and fatty, cause hormonal imbalances that promote overeating, the scientist who authored the study claimed. These imbalances leave a person hungrier, less willing to exercise, and feeling less good overall.

Although the research focused on childhood obesity, overweight kids tend to become overweight adults, he said. 

That, he added, helps explain why health experts throughout Western countries are lamenting an “obesity epidemic” population-wide. 

“If we don’t fix this, our children will continue to lose,” said the researcher, Robert Lustig of the Children’s Hospital at the University of California, San Francisco. 

His findings appeared in a review of obesity research, published in the August edition of the research journal Nature Clinical Practice Endocrinology & Metabolism. A related paper by Lustig is to appear in the November issue of the journal Pediatric Annals.

Obesity is now the most commonly diagnosed childhood ailment, said Lustig, who directs the hospital’s Weight Assessment for Teen and Child Health Clinic. Diseases once seen only in adults, like type 2 diabetes, now are occurring in children. 

Weighty children are also ostracized and teased, sometimes causing long-term psychological damage, he said. Obese adults, meanwhile, face greater risk of high blood pressure, heart disease, and stroke.

Today’s sugary, low-fiber, fatty foods boost levels of the hormone insulin, Lustig said. This, in turn, encourages overeating because insulin promotes a signal that induces the body to seek a pleasurable feeling that comes from eating. This sensation comes from the brain chemical dopamine.

Insulin also promotes overeating in a second way, Lustig added, by suppressing the effectiveness of another hormone, leptin. Leptin, when functioning properly, “increases physical activity, decreases appetite, and increases feelings of well-being,” he said. Its suppression results in greater appetite and lowered well-being.

Lustig blamed changes in food processing during the past 30 years, particularly the addition of the sugar fructose to a wide variety of foods that once never included sugar and the removal of fiber. Both changes promote insulin production, he said. 

Excessive fructose and inadequate fiber, in particular, “appear to be cornerstones of the obesity epidemic through their effects on insulin,” he added. High fat and low dairy content contribute to the problem, he added.

According to the National Institutes of Health, the number of children who are overweight in the United States has doubled during the past three decades. Currently one child in five is overweight. The increase is true for children and adolescents of all age groups and races and for boys and girls. 

Lustig said the notion that children are responsible for their own weight, or excess of it, no longer holds up. Society is to blame for giving kids toxic food, he said, and it has to stop.

“No child chooses to be obese,” he said. “Furthermore, young children are not responsible for food choices at home or at school, and it can hardly be said that preschool children, in whom obesity is rampant, are in a position to accept personal responsibility.”

Moreover, he said, research shows that in recent times even thin people are gaining weight, belying the notion that a small number of gluttons alone are behind the obesity crisis. “Whatever is happening is happening to everyone,” he wrote.

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