Critics say the body mass index is flawed and cannot be applied equally to everyone. For example, many professional athletes fall outside the health boundaries set by the scale, because of their height or muscle mass.
Stelman is 1.7 meters tall (5-foot-7) and says she weighs around 60 kilograms (132 pounds) — but she isn't quite sure.
"I never weigh myself. I don't care. I don't even have a scale," she said. "Weight is just a number. As long as I feel good and healthy — that's all that matters."
One of the main supporters of the new legislation is Adi Barkan, one of Israel's top model agents.
In 30 years of work, he says he has seen young women become skinnier and sicker while struggling to fit the shrinking mold of what the industry considers attractive.
He said Europe's fashion has started shifting back. "They understand that something has to change," said Barkan, noting the rampant use of Photoshop, the popular picture editing computer program, to make models look even skinnier.
The Israeli law requires that any advertisement published for the Israeli market must clearly disclose whether the models' appearance was altered by digital manipulation.
Israeli designer Keren Saban said she prefers models who display her clothes to be "someone who looks like a woman."
"A woman's look is not something you need to be ashamed of, just the contrary," said Saban. "That is what an item should look like when we sell clothes to women."