Rats preferred sugar over cocaine
In 2007, Magalie Lenoir (University Bordeaux, France) conducted an experient to see if rats preferred
sugar over cocaine.
The rats, who were not thirsty or hungy, were given two water bottles.
One had refined sugar (sucrose) or saccharin. One had cocaine.
They found that 94% of the rats preferred sugar over cocaine.
Their theory is that, sugars only used to be available in very low quantities in foods,
which the brain has evolved around.
Refined sugars then create a "supranormal" reward, deep in the brain.
It has the potential to override self-control mechanisms and therefore lead to addiction.
An extension of this study, in 2012, found a 50/50 preference between sucrose and heroin, which is thought of
as a more addictive drug for humans.