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Junk food may be addictive

BMJ 2003; 326 doi: (Published 01 March 2003) Cite this as: BMJ 2003;326:030350a
  1. Balaji Rangarajan1
  1. 1Birmingham

Eating junk food may be addictive, claims recent American research. This comes in the light of recent law suits against fast food restaurants for health problems related to obesity.

Scientists in the United States have shown that rats given a diet containing one quarter sugar have cravings for sugar once they are denied of it. The rats showed symptoms of anxiety, including chattering teeth and shaking, which are similar to those seen in people with nicotine or morphine withdrawal. “The implication is that some animals, and by extension some people, can become overly dependent on sweet food,” stated John Hoebel, a psychologist at Princeton University in New Jersey.

The research implies that hamburgers, chips, and other snacks rich in calories may be similar to heroin and other drugs in the way they bring about addiction. Fatty junk food may produce hormonal changes and centrally increase the release of opioids. The brain is stimulated to release its own natural opioids, which, like morphine and heroin, have stimulating and addictive affects. In essence, the study found that we get hooked on our own opioids and crave for more.

Anne Kelley, a neuroscientist at the University of Wisconsin Medical School in Madison, found that if rats' brains were stimulated with a synthetic version of the natural opioid enkephalin, they ate up to six times their normal intake of fat. They also ate more sweet, salty, and alcoholic solutions.

“Overindulging in tasty food led to marked and long lasting changes in the rats' brain chemistry similar to those caused by extended use of morphine or heroin,” she said. “This says that mere exposure to pleasurable, tasty foods is enough to change gene expression, and that suggests that you could be addicted to food.”


Originally published as: Student BMJ 2003;11:50

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