Israel has blocked its media, websites and catwalk shows from using overly thin models or those with a low body mass index.
The law aims to protect impressionable teenagers from eating disorders.
Officials estimate some 30 young adults and teenagers die each year of anorexia or bulimia.
In addition, any advertisement altered by graphics programmes has to be labeled with a warning that the image has been distorted.
BMI is defined as an individual’s weight in kilos divided by the square of his or her height in metres.