The awareness-raising initiative is the result of a partnership between charity New Give Up onlus.and the Association of Italian municipalities (Anci).
Never Give Up Onlus was founded in 2014, with the mission to raise awareness, prevent and intercept risk factors and treat eating and nutrition disorders at an early stage.
"Illuminating monuments and squares in lilac is a gesture with a strong symbolic value and we hope it will help draw attention to such a serious and widespread problem, which requires immediate attention from everyone," Anci President and Mayor of the Puglia regional capital Bari, Antonio Decaro, said.
More than three million Italians have problems with food, weight and body image, that if not properly intercepted can turn into eating disorders.
Anorexia and bulimia are the leading cause of death due to illness among 12-25 year olds in Italy, according to Never Give Up.
"If caught and treated in time, eating disorders can be cured, but unfortunately only 10 per cent of sufferers seek help and it takes an average of three years for them to do so," Stefania Sinesi, the charity's scientific director, said.
"This is why it is crucial to shed light on these disorders in order to break the silence and raise awareness of the importance of seeking help early on," she concluded.
ANSA