Chairing a British Nutrition Foundation seminar: titled Food addiction – what is the evidence?, Professor John Blundell, chair of psychobiology at the University of Leeds, outlined why research with animals supposedly showing a link between certain foods and addiction were scientifically flawed.
While eating can deliver pleasurable messages to the brain, this doesn’t make it addictive, he said. “Overconsumption of food represents overconsumption in our culture,” he said. “So we don’t need a neuro-chemical theory to explain it.”
‘Risk of addiction’
Professor Peter Rogers from the School of Experimental Psychology at the University of Bristol, said the increasing debate about food addiction was “an excitable topic generating a lot of heat”. He said the risk of addiction to foods of any sort was low and instead suggested “energy density is a key factor in increasing energy intake”.
Rogers also questioned the relevance of many of the “intermittent access models” used in studies to prove links between certain foods and addiction. “Craving is a part of normal appetite control,” he said. He cited people’s attempts to control their intake of foods such as chocolate, which they consider to be “nice but naughty”, to make his point.
“It’s that resistance which causes the instances of craving,” said Rogers. And it is this that leads some people to attribute addictive properties such as ‘chocoholic’ to their responses to certain products.
Graham Finlayson, an associate professor in biopsychology at the University of Leeds, said that while clinicians found food addiction theories “highly contentious”, public perception was generally that it was a real phenomenon.
‘Questionable animal studies’
“It’s a concept that resonates with people,” he said, and added that studies had found that around 79% thought sugar was addictive. These beliefs had been reinforced by an “explosion” in questionable animal studies on food addiction since 2008, he added.
And yet “no link had been established between food addiction and hyper-palatable foods”, he concluded. “Food addiction is too loaded a term.”
Reviewing the neuroscience in food consumption, Professor Sadaf Farooqi from the University of Cambridge explained how the hormone leptin helped modulate messages the brain received on satiety and how its deficiency could lead to obesity. “Leptin is a pivotal regulator of the human energy balance,” said Farooqi, particularly in children. “Eating behaviour can be highly controlled with hormones such as leptin.”
However, Farooqi also said there was no convincing neuroscientific evidence to support the concept of food addiction in humans.