New York author and journalist Marisa Meltzer never got to meet the subject of her latest book. In fact, she only became aware of Jean Nidetch after reading her obituary in the New York Times.

“It had never occurred to me that there was even a founder of Weight Watchers, I just thought it was some kind of corporate thing,” says Meltzer from her Brooklyn apartment. “And at first I was like, oh now I have a face and a name to blame all my pain on. But then I read the obituary and was just really intrigued by this working-class Jewish housewife from Brooklyn who had this fairytale version of the American dream. I wanted to know more.”

This was the beginning of a journey for Meltzer, who has been struggling with yo-yo dieting and body issues her whole life. Not only did she decide to give Weight Watchers another go (the first time was at the tender ago of nine) but to also delve into the life of Nidetch, born Jean Slutsky in 1923. “One of the interesting parts is that it all starts in middle age — it’s not really a story you hear about women, especially women in the early 1960s when she had to have her husband’s signature on her first lease,” says Meltzer. “Everything about it was so fascinating and emotionally complex and I was surprised that no one had told her story, especially since we’re in this era where culturally we’re interested in women who haven’t got their due,” she explains.

Nidetch’s life story — how she was hurtfully fat-shamed in a supermarket by an acquaintance, finally kicking her food habit through to the beginnings of Weight Watchers in the 1960s when she discovered that what women really needed was a safe space to talk about their weight, and on to global success and stardom — runs parallel with Meltzer’s own dieting up and downs. There’s also a fascinating deep dive into the insatiable rise of the multibillion-dollar food and diet industries that have turned America into one of the fattest nations in the world.

Nidetch, for all her charm and chutzpah, was not perfect after all, discovers Meltzer. Although she had lost copious amounts of weight and became the public face of Weight Watchers, it’s quite possible that she struggled to keep the pounds off; and that she replaced eating with the thrill of gambling. “I think everyone has some sort of preferred release,” says Meltzer, who writes about wellness and beauty for a living. “For some people it’s smoking or alcohol, for other people it’s shopping or running. But it’s complicated because not all of those things are considered vices.”

The book charts Weight Watchers’ transformation from a dieting company (Meltzer gleefully lists vintage recipes: “Frankfurter spectacular”, anyone?) to a wellness empire, following the trend of how the language around dieting and eating has changed. But, writes Melzter, even if the words have changed, our relationship with our bodies hasn’t. More often than not women, and it’s mostly women, are made to feel inadequate about how we look. The struggle for Meltzer, like for so many, is how to just exist in her body and not have to think about it — or what she wants to eat that day.

We talk about the visibility of larger women such as Lizzo or Lena Dunham in popular culture. Look, they say, you can be like us and still be successful, something that would probably have been impossible even a few decades ago. But Meltzer is ambivalent about the new body positivity movement, the implication being that if you fail to love your body on any given day, the fault lies with you rather than the myriad messages we constantly internalise.

“I wish that body positivity would allow for negativity — no one feels positive about anything all of the time. I think it’s great to try to widen beauty standards. There have been some small in-roads made —plus-size models in high fashion magazines — but they’re baby steps.”

Although both women are Jewish, Meltzer’s own experiences aren’t linked to her heritage so much as her North Californian upbringing.

“Jewish communities in the US are regional,” she explains. “I, for example, didn’t grow up with an observant family at all. Our connection to Judaism was pretty much just cultural, so I think for families like mine there was this great love for things like bagels and Reuben sandwiches and the connection was through food, but the food was also off limits to me because it was all considered very rich.”

It’s fair to say that food and Judaism go hand in hand, with special dishes for each holiday — and always second helpings of latkes, kugel and brisket, which are bound to leave a mark on the body, as well as Jewish women’s relationship to their appearance.

They’re not immune to societal pressures — Meltzer befriends an Orthodox Jewish woman in one of her Weight Watchers meetings.

Despite its many transformations, Weight Watchers International — renamed WW International in 2018 — is still going strong nearly six decades after Jean’s idea first took off. What does Meltzer think has been its enduring appeal?

“I think it was Jean’s original idea that people on diets could educate each other, find solace in each other. And it counteracts this idea that to be fat was to be lonely and have no friends.”

What’s particularly pleasing about this warm book is the weighing up of what “success” can look like for different types of people. Nitdetch was married to a regime of strict dieting and self-denial in exchange for a life of glamour and admiration — a process that Meltzer finally decides she could never truly commit to. After a year of attending meetings, “I was able to make peace with the fact that life will probably always have some kind of diet in it — and I feel fine about it,” she says.

It turns out that in the end, success comes in all shapes and sizes.

This is Big – How the Founder of Weight Watchers Changed the World — and Me is published by Chatto & Windus