By . Anna Hodgekiss . Just can't stop? Scientists say our inability to stop eating junk food is called 'hedonic hyperphagia' It is the question that plagues anyone with a sweet tooth or those partial to a biscuit - or ten. Now, scientists claim to have partially unravelled mystery of why some snacks seem impossible to eat in small amounts. While some might call it greed, another name for such behaviour is 'hedonic hyperphagia,' says German scientist Dr Tobias Hoch. 'That's the scientific term for eating to excess for pleasure rather than hunger. 'It's recreational over-eating that may occur in almost everyone at some time in life - and the chronic form is a key factor in . the epidemic of overweight and obesity.' Dr Hoch and his team from the University of Erlangen-Nuremberg in Germany scanned the brains of rats as they ate either crisps, a powdery mixture of fat and carbohydrates, or ordinary chow pellets. The rats were far more keen on the crisps, despite the fat and carbs mixture containing the same number of calories. Standard pellets were the least popular food. 'The effect of potato chips (crisps) on brain activity, as well as feeding behaviour, can only partially be explained by its fat and carbohydrate content,' said Dr Hoch. 'There must be something else in the chips that make them so desirable.' High levels of fat and carbohydrate had been thought to send pleasing messages to the brain, leading people to gorge on calorie-packed snacks. The magnetic resonance imaging scans showed that reward and addiction centres in the rats' brains were most active when they ate crisps. Food intake, sleep, activity and movement were also stimulated differently by crisps compared with other food. 'By contrast, significant differences in the brain activity comparing the standard chow and the fat carbohydrate group only appeared to a minor degree,' Dr Hoch added. There must be something special about the crisps that was sparking the rats' interest, he said. One theory is that there are  triggers in snacks and sweets that stimulate the brain's reward centres. No stop valve: Some people may have differing sensitivity to reward signals from food -  which may explain why some of us are more susceptible to moreishness than others . And some people may have differing sensitivity to reward signals -  which may explain why some individuals are more susceptible to moreishness than others, the scientists believe. 'Possibly, the extent to which the brain reward system is activated in different individuals can vary depending on individual taste preferences,' said Dr Hoch. 'In some cases, maybe the reward signal from the food is not strong enough to overrule the individual taste.' He added that pinpointing the molecular triggers in snacks and sweets that stimulate the brain's reward centres could lead to the development of new drugs or food additives that combat over-eating. Identifying the triggers is the German team's next project. The findings were presented to the annual meeting of the American Chemical Society in New Orleans.
Some of us may be more sensitive to the reward signals from food .
This means we are more susceptible to moreishness than others .
But we are all guilty of hedonic hyperphagia - the scientific term for eating to excess for pleasure rather than hunger, say the German researchers .
By . Anna Hodgekiss . Just can't stop? Scientists say our inability to stop eating junk food is called 'hedonic hyperphagia' It is the question that plagues anyone with a sweet tooth or those partial to a biscuit - or ten. Now, scientists claim to have partially unravelled mystery of why some snacks seem impossible to eat in small amounts. While some might call it greed, another name for such behaviour is 'hedonic hyperphagia,' says German scientist Dr Tobias Hoch. 'That's the scientific term for eating to excess for pleasure rather than hunger. 'It's recreational over-eating that may occur in almost everyone at some time in life - and the chronic form is a key factor in . the epidemic of overweight and obesity.' Dr Hoch and his team from the University of Erlangen-Nuremberg in Germany scanned the brains of rats as they ate either crisps, a powdery mixture of fat and carbohydrates, or ordinary chow pellets. The rats were far more keen on the crisps, despite the fat and carbs mixture containing the same number of calories. Standard pellets were the least popular food. 'The effect of potato chips (crisps) on brain activity, as well as feeding behaviour, can only partially be explained by its fat and carbohydrate content,' said Dr Hoch. 'There must be something else in the chips that make them so desirable.' High levels of fat and carbohydrate had been thought to send pleasing messages to the brain, leading people to gorge on calorie-packed snacks. The magnetic resonance imaging scans showed that reward and addiction centres in the rats' brains were most active when they ate crisps. Food intake, sleep, activity and movement were also stimulated differently by crisps compared with other food. 'By contrast, significant differences in the brain activity comparing the standard chow and the fat carbohydrate group only appeared to a minor degree,' Dr Hoch added. There must be something special about the crisps that was sparking the rats' interest, he said. One theory is that there are  triggers in snacks and sweets that stimulate the brain's reward centres. No stop valve: Some people may have differing sensitivity to reward signals from food -  which may explain why some of us are more susceptible to moreishness than others . And some people may have differing sensitivity to reward signals -  which may explain why some individuals are more susceptible to moreishness than others, the scientists believe. 'Possibly, the extent to which the brain reward system is activated in different individuals can vary depending on individual taste preferences,' said Dr Hoch. 'In some cases, maybe the reward signal from the food is not strong enough to overrule the individual taste.' He added that pinpointing the molecular triggers in snacks and sweets that stimulate the brain's reward centres could lead to the development of new drugs or food additives that combat over-eating. Identifying the triggers is the German team's next project. The findings were presented to the annual meeting of the American Chemical Society in New Orleans.
scientific term for eating to excess for pleasure rather than hunger. 'It's recreational signals from food -  which may explain why some of us are more susceptible to moreishness than sensitivity to reward signals -  which may to moreishness than others, the scientists