Much of this summer, an influencer named Emily Gellis Lande has been on a campaign, posting on Instagram dozens of times a day about the dangers of a diet called F-Factor.
Ms. Gellis, 34, has never been on the diet. She relays anonymous stories from women who say that after beginning the diet they experience long-lasting rashes, intense cramps, even indications of metal poisoning, and that the diet encourages disordered eating.
The stories are anonymous, she said, because the women are afraid to criticize Tanya Zuckerbrot, the Instagram-famous registered dietitian who created the diet.
Ms. Zuckerbrot, 48, has built a substantial business around the diet, with clients who have paid as much as $25,000 for her help in getting on the high-fiber diet. She has a product line of powders and bars and books that lay out her systems.
And she has extreme wealth that she puts on ample display. She has a $22 million Park Avenue apartment and an Instagram account loaded with bikini beach-bod photos taken in luxurious spots like Dubai and the Seychelles.
But now, since Ms. Gellis’s campaign began, Ms. Zuckerbrot and her husband, Anthony Westreich, a corporate real estate investor, have been harassed and defamed, she said. She has brought in lawyers. On Sunday afternoon, she hired Lanny Davis, once the White House special counsel to former President Bill Clinton; his client list more recently includes Michael Cohen.
Ms. Zuckerbrot said that, with 176,000 purchase orders since she began selling the powders and bars two years ago, she has received just 50 complaints about gastric distress or rashes.
Ms. Zuckerbrot said her diet and products are safe; she questioned Ms. Gellis’s authority.
“I believe in her mind she thinks she’s helping people and that the lifestyle I lead is poisoning everyone and giving them anorexia,” Ms. Zuckerbrot said of her online antagonist. “But she’s a fashion blogger. She doesn’t work for the World Health Organization. If this was Barbara Walters or John Stossel, maybe I would have paid attention sooner. But this is a young woman who has no credential in health and wellness or any medical or clinical experience. The girl sells clothing for a living.”
Ms. Zuckerbrot’s success has come from making the diet more than a weight loss rule book. It’s a lifestyle — she said she has worked with Megyn Kelly and Katie Couric and is the official dietitian to the Miss Universe Organization — with the attendant merch.
Among the half-shirts and sweatshirts sold on the diet’s website, there is an F-Factor “intentions bracelet,” to be worn on the “hand that will either undermine your intentions or honor them” as it “holds the fork, reaches for the bread basket or dips into the candy dish.” It costs $18.
Ms. Gellis said that she did not anticipate that her posts would spiral. “Never in my life did I imagine I would be wrapped up in the story line I am right now,” she said. But in receiving messages from hundreds of women, and speaking on the phone with many of them about their physical and emotional pain, “I realized I simply could not let them down,” she said.
“I wish the F-Factor team would acknowledge that pain,” she said. “But that’s simply not how this story goes.”
Ms. Gellis, who posts about easygoing, moderately priced outfits and cosmetics, was inspired to action by an anonymous Instagram post from someone who said she was a former client of Ms. Zuckerbrot’s. That client said she had been told she should consider going off antidepressants because they could be contributing to weight retention or gain.
“This is a lie, this never happened and it never would happen,” Ms. Zuckerbrot said.
After seeing the Instagram post, Ms. Gellis flipped on her camera to make videos about the importance of mental health care and doctor-prescribed antidepressants. Soon, she found that the more she posted about F-Factor, the more dieters she heard from — women who agreed that Ms. Gellis could share their experiences if she just kept their names private. “I got this onslaught of messages from people,” she said.
Some women who fed Ms. Gellis tips recounted their stories to The New York Times. One said she was 32 when she went on the diet and within a month developed abdominal pain so severe that she went to the doctor and to the emergency room and underwent two CT scans. (She shared her F-Factor receipts and medical records with The Times.)
Another woman, who said she was underweight, paid $20,000 to become Ms. Zuckerbrot’s client. (She also shared her receipts.) The regimented nature of the program exacerbated her issues with food, she said, and after eight months of drinking shakes made with the F-Factor powder, the woman developed excruciating red spots that required a biopsy.
Both these women said these symptoms disappeared when they stopped the diet.
Ms. Zuckerbrot said she rarely accepts underweight clients. Via her lawyer Mr. Davis, she named two previous clients who matched the description of the underweight woman, and provided their weight and health details, saying that in both cases she helped the women gain, not lose, weight.
“I don’t understand why people would not come forward publicly if they believe my product has hurt them,” Ms. Zuckerbrot said.
Probably the two most distressing charges received by Ms. Gellis was that the diet and its products caused women to miscarry. This accusation was also published by The New York Post, Refinery 29 and PerezHilton.com.
But one of those tips, at least, was a sting.
After Ms. Gellis and others published about miscarriage, Ms. Zuckerbrot and Eva Chen, an Instagram executive, received an email saying the story was fake and taking credit for the trick, from the address firstname.lastname@example.org.
“It is a FULL OUT LIE,” the email said. “I have never used Tanya’s products.” The writer included a video documenting her exchange with Ms. Gellis.
The miscarriage story and confession email was sent by Alison Brettschneider, 44, a former Instagram influencer herself and the daughter of the civil rights lawyer Alan Hirshman, who died of complications of Covid-19 in April. As her email address indicates, she sees herself as a soldier in a culture war over publishing on social media the stories of anonymous sources — describing the “trend” as “irresponsible and dangerous,” her email said.
She is no stranger to Instagram strife. Back in the summer of 2018, Rachel Cargle, a public academic, asked her followers to tag their favorite white feminists who hadn’t made note of the death of Nia Wilson, a young Black woman who was stabbed to death in a BART station in California.
Ms. Brettschneider was tagged and then became the subject of the conversation by making it a “circus,” Ms. Cargle wrote, turning “the post into many many things including white savior complex, white tears, exceptionalism, performance activism, guilt projection and all over white privilege.”
Ms. Brettschneider is still fuming about it. “I’m the last person who is racist,” she said on the phone, while driving her children in the Hamptons. “I’m like AOC. My whole Instagram was known for speaking up.” Early this year, she said, she’d spent a month in Alabama trying to prevent the execution of Nathaniel Woods.
But last fall, Ms. Brettschneider said, her Instagram account was disabled without notice. She immediately reached out to higher-ups at Instagram and was told it was because of three posts that had violated their guidelines. “They said my language was bullying,” she said.
She is now suing Instagram. Her lawyer is Lauren Faraino, who represented Mr. Woods. (Instagram declined to comment on the specifics.)
Why did she send the email? Ms. Brettschneider said she couldn’t stand by silently and watch Ms. Zuckerbrot be attacked by anonymous sources, even knowing she may be attacked herself when her trick was revealed. “Someone has to sacrifice themselves,” she said.
As it happens, she is also no stranger to Ms. Zuckerbrot. Her cousin, Amanda Karp, is F-Factor’s head dietitian.
“If someone makes up a lie in order to discredit the voices of thousands of women who have suffered, in order to be a part of an Upper East Side ‘cool moms’ clique, I think that speaks to exactly what that person stands for,” Ms. Gellis said. “This isn’t ‘Mean Girls.’ This isn’t high school. There are women’s lives on the line.”
The diet begins with a maximum of 1,200 calories and a lot of fiber. Dieters are allowed a handful of GG crackers daily — the Scandinavian bran crispbread that identifies F-Factor enthusiasts. Dieters graduate to additional steps that add more carbohydrates — and adhere to the “Three Bite Rule.” (You may have three bites of any indulgence.)
Elizabeth Savetsky, an influencer, has been doing F-Factor since becoming a client of Ms. Zuckerbrot’s in 2018. “I had heard amazing things about it from my fellow mamas on the Upper East Side,” Ms. Savetsky, 34, wrote in an email. She said she’d experienced a second pregnancy loss and was suffering with other health issues. On the diet, she said, her “lifelong issues around food went out the window.”
Ms. Savetsky’s fees were waived by F-Factor in exchange for sharing her “journey on social media,” said Mr. Davis, an arrangement that ended in June, 2019.
Medical professionals have had concerns about the diet for years, said Dr. Tom Hildebrandt, the chief of the Center of Excellence in Eating and Weight Disorders at the Icahn School of Medicine at Mt. Sinai.
“Our patient population is particularly vulnerable to diets with highly branded promises,” he said. The messaging is particularly concerning “when you match it with a diet like this one that requires you to eat very little nutrition and to approach food in a very regimented, controlled way.”
Ms. Zuckerbrot questioned the doctor’s sincerity and concern. “Why hasn’t he reached out to me and said, ‘Tanya, your program is harming people? If he has such altruistic motivations, why hasn’t he reached out to me?”
She also pointed out that the back cover of her diet book is heaped with praise from doctors. (“Tanya’s scholarly approach is a gift that gives forever,” said Dr. Jerome Zacks, a cardiologist and associate clinical professor at the Mount Sinai Health System, in one blurb. “Her contribution to preventive health care is immeasurable.”)
Two former staff members of her clinic spoke about their time with Ms. Zuckerbrot. Alix Turoff, now a registered dietitian, worked as an intern in 2009. She credits Ms. Zuckerbrot as an inspiration, but also said that the culture inside the office, where she said dressing up in heels and form-fitting clothes was encouraged and eating a lot was not, created the foundation for the work the dietitians did with clients.
“The culture was a pursuit of thinness at any cost,” she said.
In her own practice now, Ms. Turoff said, she sees many patients wanting help to create normal eating habits after trying, sometimes for years, to live the F-Factor way. “They often are in patterns of bingeing.”
Ms. Zuckerbrot shared a Dropbox folder with 53 social media videos and screenshots of text message exchanges between her and Ms. Turoff that document Ms. Turoff’s appreciation of opportunities offered by Ms. Zuckerbrot and detailed Ms. Turoff’s recommendation to her own clients to try a high-fiber diet.
Lisa Moskovitz, a registered dietitian, also worked for Ms. Zuckerbrot, about 10 years ago. “I learned a lot from her,” Ms. Moskovitz said. “She is an incredible businesswoman.”
She said the values around glamorized wealth and extreme thinness have only been proselytized wider as Ms. Zuckerbrot’s renown has grown.
“With any type of diet or nutritional advice on social media, it is so easy to get caught up in the idea of the life it can give you,” Ms. Moskovitz said.
“You have to understand, she and anyone you see on social media and in the broader media, if they look a certain way, it is not because they’re eating fiber,” she said. “It’s genetics and various other things that can be bought and Photoshopped.”
Ms. Zuckerbrot said she had fired Ms. Moskovitz.
“We did not share the same philosophy,” Ms. Moskovitz said.
Awaiting the Lab Results
Critics of the F-Factor, including Ms. Gellis and her supporters, have asked Ms. Zuckerbrot to release a certificate of analysis — a statement from a third-party lab confirming a product has been tested for contaminants like microbes, pesticides and heavy metals.
Ms. Zuckerbrot had repeatedly declined, saying the information is proprietary, but now says she will release the information “in days, not weeks.”
“Because of all the misinformation and accusations of high levels of lead,” she said, “our true customers are now concerned.”
She also said — via Mr. Davis — that this experience has led her to believe she should be “more thoughtful about the images I have showed about myself and my lifestyle” and she planned to be more mindful in the future. “The goal of my message is to always look and feel your personal best regardless of weight because you are so much more than a number on a scale,” she said.
For her part, Ms. Gellis is asking her followers to mail her samples of Ms. Zuckerbrot’s products bought before the public scrutiny on their safety began, and plans to have those products tested.
Ms. Gellis was on vacation in August in Montauk, N.Y. with her husband, Michael Lande, but didn’t take a break from her Instagram campaign. “Trust me, I haven’t even scraped the surface of how much this person sucks,” Ms. Gellis said on Instagram this week (adding a profanity). She promised there was more to come. “Honestly it’s gossip but like I’m pretty sure a lot of it is true.”
She is inflamed by what she sees as Ms. Zuckerbrot’s refusal to acknowledge that perhaps the women registering complaints, anonymously or not, are credible.
“At first I was like, ‘What the hell is she doing?” Mr. Lande said of his wife’s avocation. “‘Why is she getting involved?’ Then I started reading these stories from these poor girls with body dysphoria and all sorts of physical problems, and I changed my mind. There needs to be some discourse on this diet. Ultimately, I feel like my wife has become a modern-era Erin Brockovich.”