Cookie Monster is a blue Muppet character on the long-running PBS/HBO children's television show ‘Sesame Street’. Since no one is born with a cookie obsession, it stands to reason he wasn't named Cookie at birth.

His real first name, as Cookie himself revealed in a 2007 episode of ‘Sesame Street’, is Sidney (Sid for short). At that time, the character sang a song entitled “The First Time Me Eat Cookie”:

🎶 The first time me eat cookie / When me was very small / Me had never ever tasted cookie at all / Me was just a mild-mannered little kid / In fact, back then me think me name was Sid. 🎶

‘Sesame Street’ insiders report that it was only after that first taste of cookie that his voracious appetite and love for the sweet treat emerged, turning him into the cookie-devouring monster we know today.

Cookie (née Sidney) is probably best known for his constant craving, messy eating habits and his favorite catchphrase, "Me want cookie!". However, he does seem to have an awareness of healthy eating habits, and readily admits that he enjoys fruit, carrots, hummus and eggplant.

In 2006, in response to growing concerns about record levels of childhood obesity in the U.S., ‘Sesame Street’ began airing segments titled ‘Healthy Habits for Life’. The following year, in a appearance on Martha Stewart's TV program, Cookie Monster explained his new philosophy: "Cookies are a sometimes food."

*Rumors that his name may be changed to Veggie Monster have been vehemently denied.

More Info: en.m.wikipedia.org