New science suggests that overeating is less a product of lacking willpower or the hormonal imbalance, but rather an addictive behavior triggered by the combinations of ingredients in modified foods, especially with specific proportions of certain fats and sugars.
The attractiveness of modern meals can overwhelm the evolutionary mechanism of regulating consumption by the brain, no longer well adapted to tempting abundance.
Hedonistic approach to eating can gradually override the signaling of the reward systems, and create a paradoxical situation when the more this person eats, the more they crave, despite heightened amounts of appetite-suppressing hormones in blood, actual nutritional needs of the organism, or the dangers of obesity, which can also cause a hormonal imbalance.
Appetite-controlling hormones like leptin and insulin affect reward pathways and feeding circuits in the hypothalamus. Few people have genetic defects that influence either the secretion or the response to those hormones in cells.
Modeling excessive feeding behavior after drug addictions can be useful if it enables predictions of outcomes by various treatments. The similarities are obvious: overconsumption stimulates reward systems, the reward gets weaker, getting more to gain a temporary pleasure, and inability to suppress a behavior with negative consequences results in a vicious cycle - compulsive habit, attempting to abstain, relapsing. The differences must be found.
During fasting, food-related reward circuits in the brain are hormonally activated, especially the striatum, that contains high concentrations of pleasure enhancing endorphins, which opiates can mimic. And then during eating, the digestive system reduces the pleasure by releasing hormones with opposite signaling. Natural food becomes less attractive, but artificially appetizing foods override this action, plus stimulate the release of motivation increasing dopamine. Obesity is caused by an overpowering pleasure seeking.
