Could high GI foods be addictive?

Posted by Editorial on 13th January 2009

New Zealand scientists have reported that heavily processed foods with a high glycaemic index (GI) could be addictive in a similar way to drugs.

Simon Thornley, from the Auckland Regional Public Health Service, noted that foods with a high GI caused blood-sugar levels to escalate suddenly, with the resultant sugar rush stimulating the same areas of the brain associated with addiction to drugs such as nicotine. Low-GI foods, on the other hand, provide a more steady release of sugar.

He believes that high sugar and fat products are often consumed because they are addictive. “The key component of those foods which may predict their addictive potential is glycaemic index or how fast you get a sugary hit,” he told ABC radio. “We’ve looked at some of the issues around automaticity or the sort of automatic nature of eating. The food environment seems to determine people’s ability to eat. If sugary foods are around, not surprisingly, they seem to be eaten more frequently.”

Mr Thornley did admit that much more research needed to be completed before a conclusion could be reached, with extensive studies comparing food withdrawal symptoms to nicotine withdrawal symptoms to be carried out.

Professor Boyd Swinburn, from Deakin University in Melbourne, queries some of the suggestions of the study. “Any addictive type of hypothesis can’t explain the rise that we’ve seen over the last 20 to 30 years of obesity,” he said on ABC radio. “It’s not that the whole population becoming more of an addictive personality type. I think there are other factors to explain obesity at a population level.”

“I think the processes within the brain, of how the brain handles drugs like nicotine and how the brain handles nutrients like glucose are very different indeed,” Professor Swinburn added. “People do get comfort from eating certain foods and enjoy certain foods. So there is this concept of comfort eating.”

“But to label it as an addiction akin to a drug addiction I think is taking the analogy too far and there’s a lot of data which would need to be demonstrated to prove that.”

The study comes after a Princeton scientist last month suggested that sugar could potentially be addictive in a similar manner to drugs. Professor Bart Hoebel and his team noticed behavioural changes in rats that were trained to become dependent on high doses of sugar.

Lab animals, in Hoebel’s experiments, that were denied sugar for a prolonged period after learning to binge worked harder to get it when it was reintroduced to them. They consumed more sugar than they ever had before, suggesting craving and relapse behaviour. Their motivation for sugar had grown. “In this case, abstinence makes the heart grow fonder,” Professor Hoebel said.

He admitted that more research needed to be done to understand if there were indeed any implications for humans and some scientists within the field of food and its impact on cognitive function have said that sugar addiction is unlikely in humans as sugar addiction has only ever been shown when extremely high doses have been administered to lab animals.