Our findings clearly demonstrate that intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals. We speculate that the addictive potential of intense sweetness results from an inborn hypersensitivity to sweet tastants. In most mammals, including rats and humans, sweet receptors evolved in ancestral environments poor in sugars and are thus not adapted to high concentrations of sweet tastants. The supranormal stimulation of these receptors by sugar-rich diets, such as those now widely available in modern societies, would generate a supranormal reward signal in the brain, with the potential to override self-control mechanisms and thus to lead to addiction. 20
In another interesting study, Oreo cookies were found to be as addictive as cocaine.21 In a different study, obese subjects showed greater activation in the bilateral hippocampus/parahippocampal gyrus, but lean subjects showed more activation in the posterior insula portion of the brain.22 Some scientists have speculated that exorphins from food may have lead humans to initially adopt agriculture,23 which was a more laborious and challenging way of life.
Cereals and dairy foods are not natural human foods, but rather are preferred because they contain exorphins. This chemical reward was the incentive for the adoption of cereal agriculture in the Neolithic. Regular self-administration of these substances facilitated the behavioral changes that led to the subsequent appearance of civilization.
Other studies have delved into the rewarding properties of both high caloric, and neurologically rewarding foods, such as chocolate.24 Chocolate ‘cravers’ elicit completely different responses, neurologically, than ‘non-cravers.’
In addition to ‘craving,’ there is a host of activity seen within the human brain, in response to rewarding foods or food-based cues.25 Activity is seen in the orbitofrontal cortex, amygdala, insula, nucleus accumbens, dorsal striatum, and many other regions.
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