It's true. They just did a study on it, with the results in the news today. It's as addictive as cocaine!!
Scientists used rats to study the effect of junk food on the brain. Rats were given access to junk food and they found that the pleasure centres of the brain reacted in the same way as when rats are given illegal drugs like cocaine. Rats that did not have access to the junk food did not have the same changes in brain activity.
The scientists also SHOCKED the rats on their feet to let them know it was time to stop eating junk food. The ones with full access to junk food kept on eating even when they knew they would be shocked. The healthy rats with an hour access to junk food quit eating it when they knew a shock was coming. Smart little suckers!!
When the junk food was taken from the rats' diets the junk food rats went on a hunger strike! They refused to eat anything! They also experiences withdrawal-like symptoms.
It's interesting. I love junk food! I don't think I could refrain from eating another potato chip or chocolate even if I wanted to, I just do not have that kind of willpower. It's kinda scary how it is AS addictive as cocaine though. I think moderation is key!
More on the study here.