Sugar, like alcohol and cocaine, activates the brain’s reward area, causing the nerve cells to release dopamine, which in turn leads to the feeling of a positive experience. This reaction sets in motion a reinforcing pattern that helps explain why we keep coming back for more and more in order to keep getting the same good feeling.
Sugar has been around for years and years, but the big difference is the amount of sugar we eat daily, and it is on the rise. Coupled to this is the lack of physical activity in our modern, hurried and stressed lifestyles. It is estimated these days in the US that in seven hours the equivalent amount of sugar is consumed that took our ancestors in 1822, 5 days to consume – a 20 fold increase!
.http://wholehealthsource.blogspot.ca/2012/02/by-2606-us-diet-will-be-100-percent.html