Corn flakes and candy, biscuits and soft drinks may be just as addictive as cigarettes according to a group New Zealand scientists. 

 Heavily-processed foods like these which have a high glycaemic index set off an addictive sugar rush that leads to obesity. 

 The NZ scientists found that compulsive overeating has similar underlying brain functions to those that cause drug dependence. And they say that heavily-processed carbohydrates have the greatest liklihood of causing food addiction. 

 Senior researcher Simon Thornley, from Auckland Regional Public Health Service, said foods with a high GI caused blood-sugar levels to spike suddenly. This spike in blood sugar causes a "rush" and stimulates the same areas of the brain triggered by addiction to nicotine and other drugs.   On the other hand, Low-GI foods produce gradual rises in blood sugar and insulin levels, and a feeling of contentment and satiety. 

 This is the first time glycaemic index (GI) has been shown to indicate the addictive potential of foodstuffs. 

 Dr Thornley said people who binged on high-carb foods experienced symptoms of addiction - loss of control, a compulsion to keep taking higher amounts to get the same high - and they suffer withdrawal symptoms if they go cold turkey. 

 And just like those addicted to drugs and alcohol, people with a higher body mass index (BMI) had fewer brain pleasure receptors. 

 Carbohydrate addicts may benefit from getting their hit of blood sugar more slowly by eating low-GI foods.  

 "Just as slow release forms of nicotine help smokers recover from addiction, low GI foods may reduce cravings in obese or overweight populations," Dr Thornley and his team at the University of Auckland, New Zealand, wrote in the journal Medical Hypotheses. 

 GI pioneer Jennie Brand-Miller, from the University of Sydney, welcomed the study but said the assertion high-GI foods have a shorter time to peak concentration in the bloodstream is incorrect. All foods take about 30 minutes to peak, but high-GI foods peak and fall at substantially greater levels, Professor Brand-Miller said. "It's a novel idea that draws on strong evidence that glucose consumption influences levels of the feel-good chemical serotonin in the brain." 

 Last year, an editorial in The American Journal of Psychiatry proposed some forms of obesity are driven by an excessive motivation for food and should be classified as a mental disorder, or "food addiction" in the upcoming Diagnostic and Statistical Manual of Mental Disorders.  

The director of the US National Institute on Drug Abuse, Nora Volkow, wrote that the symptoms of obesity - compulsive consumption of food and inability to restrain from eating - are remarkably similar to those described for drug dependence.