This is from the Foods Matter site: http://www.foodsmatter.com/conference_reports/articles/sugar-fat-addiction-fabresearch-07-14.html#lustig
A conference titled Sugar, fat, food and addiction: New approaches to the public health crisis
I am always interested in how dramatically food affects behaviour and health so please read this to find out more.
Sugar, Hormones and Addiction.
Professor Robert Lustig, Division of Pediatric Endocrinology, University of California, San Francisco
Addiction makes a nonsense of personal responsibility. The balance in the addicted brain is off centre so that it cannot activate rational/responsible responses.
The lay public believe that food, and especially sugar, is addictive.
There are many similarities between food and drugs in terms of the areas of the brain that they effect while binge eating equates very closely with substance abuse. The only difference is that while we do not need drugs to survive, we do need food.
• When you get a pleasurable feeling dopamine is released producing a feeling of reward – but this is short lived (around one hour). It should be controlled by the frontal cortex which indicates satiety – you have had enough.
• However, with an addictive substance (such as morphine or nicotine) the dopamine response is up rated (you need more to trigger an effect) and the control mechanisms (in the front cortex) are inhibited (do not work efficiently).
• A ‘normal’ person has a lot of dopamine ‘receptors’ so a little dopamine has a relatively great effect. However, with increased, or excessive, exposure, the receptors get down regulated (become less sensitive) so you need more dopamine to get the same effect.
• Obesity inhibits the efficient functioning of the dopamine receptors so you need more food to trigger the reward the response, so the obese person’s weight increases further.
• There is also a genetic element to this as 25% of people have a polymorphism which reduces their number of dopamine receptors e.g. they need to eat or take more to achieve ‘reward’.
Leptins and insulin
• The hormone insulin originates in the pancreas.
• It controls the storage of fat in the fat cells. It is also involved in the ‘satiety signal’ – telling the brain that it has taken in enough energy/food so it should stop telling the body to eat more.
• The hormone leptin originates in the fat cells.
• Leptin tells the brain whether or not the body has enough energy for normal function. If leptin levels are low, the brain thinks that the body is short of energy so it needs to eat more (to get energy) and to do less (to preserve what energy it has).
Leptin ‘takes its lead’ from insulin so if one does not work, nor does the other. Every obese person has a problem in one or other of these areas.