The Tanya Zuckerbrot & F-Factor Drama, Explained

Content warning: This article may be triggering for people who have struggled with eating disorders.

If you’ve been on social media the past few days, you’ve likely seen the controversy between fashion and lifestyle influencer Emily Gellis Lande and Tanya Zuckerbrot, MS, RD, CEO & Founder of F-Factor. It was detailed in an explosive piece in the New York Times, but if you can’t get enough of this story or reached your monthly article limit, allow me to break it down.

First, some background: If you’re not familiar with F-Factor, you can take a scroll through its Kelly green-soaked Instagram feed to get the general gist: Yay, increased fiber consumption and lower body fat! Make a tuna-fish GG-cracker sandwich! F-Factor has been around since 2006, when founder Tanya Zuckerbrot, MS, RD published The F-Factor Diet: Discover the Secret to Permanent Weight Loss. The diet consists of three steps of high-fiber, high-protein, low-carb eating (with step 3 being maintenance). The face of the brand is Tanya Zuckerbrot, a registered dietician who flaunts a lavish lifestyle on her Instagram account. If you go to their website, you’ll find that the F-Factor approach and suggested meals “focus on combining lean protein with high-fiber carbohydrates, which are low in calories and keep you feeling full throughout the day.” As Zuckerbrot explained in a January 2020 episode of Betches’ Diet Starts Tomorrow podcast, “fiber and protein in every meal makes losing weight no big deal.” 

For some people, though, going on F-Factor proved to be a huge deal for their health. For months, I’d read and heard horror stories from people who claimed to be former F-Factor clients, specifically via Twitter, as well as the gossip-curating Instagram account DeuxMoi, which shares insider info and screenshots about various celebs and influencers. 

And then Gellis began to share stories on her Instagram, too. Although she herself had never personally been on the diet—she told Betches, I did try the powder one time and I was not a fan”—she got involved after reading an anonymous account (originally posted on the aforementioned DeuxMoi page) from a woman who claimed to have previously been on the F-Factor plan. The woman said Zuckerbrot had advised her to consider going off her antidepressants because they could be contributing to her weight gain and retention. Gellis, who’s passionate and outspoken about the importance of mental health care, became furious. 

Zuckerbrot told the New York Times, This is a lie, this never happened and it never would happen.”

Gellis began to sound off on her Instagram Stories, and it quickly snowballed from there. Currently, you can find 11 Instagram highlights and counting dedicated to discussing Zuckerbrot and F-Factor on Gellis’s page. 

Gellis initially kept the identities of her sources private, since many felt more open to speak out when they were kept anonymous, but as of Tuesday, Gellis began sharing on-the-record accounts from people who were willing to come forward publicly. “I’ve received about a thousand messages a day for two weeks straight,” Gellis told Betches. Former F-Factor clients began recounting to her that the highly restrictive regimen eventually led to disordered eating habits. Others complained about severe side effects from the products (which include protein powders and bars that were introduced in 2018), like migraines, gas, cramping, diarrhea, rashes, nausea, urinary tract infections, severe chest pains, and even heavy-metal poisoning. 

While many supported Gellis’s first attempts to speak out, with it came attacks. “I was soon met with extreme cyber-bullying attacks from private accounts threatening to ‘expose my past’ if I continue talking about this woman and her company,” Gellis explained. They’re all “burner accounts with 0 followers, 0 following, 0 posts and wacky names. New accounts pop up daily.”

Zuckerbrot eventually publicly addressed the backlash in an IGTV video, claiming she was being “cyber bullied” by two anonymous accounts in particular, both of which have since been shut down. 

In response, Gellis said on her Instagram that “to turn a conversation about people who have been harmed by your products and turn it into a conversation about cyber bullying is a low I didn’t expect the F-Factor team to go [to].” 

In any case, the attempts to silence Gellis backfired: When she began to share the threatening messages she was receiving, there was an outpouring of support. “Women started to rally around me because they had been silently suffering, and they didn’t want me to go down alone.” She’s continued to share stories every day since—especially those of people who’ve had their voices ignored on the F-Factor Instagram page, which is notorious for deleting comments from dissenters. (Zuckerbrot admitted to Insider that F-Factor deleted some negative comments from its Instagram page “when it was slander,” saying, “we felt we were following community guidelines”.)

Many of the women messaging Gellis about the diet allege that it is way overly restrictive, and, categorically, “an eating disorder”. Three F-Factor-approved meals, for example, usually clock in at around 1,000 calories a day, or even under that. One woman told Insider she experienced amenorrhea, the pausing of her period, which can be linked to anorexia. Eventually she ended up needing treatment at a NYC treatment center for six months. 

Zuckerbrot told Betches, “The F-Factor program is more than 1,000 calories per day (and often more than that based on the client’s needs, their sex, their weight, their height and their activity factor).”

The problems for some F-Factor followers didn’t end when they quit the diet, though. Some allegedly had to go to the hospital for refeeding syndrome, which is when “you’ve been eating such a low amount of calories for such a low amount of time that your body goes into shock when you start eating more calories and refeed your body,” Lauren Sharpe, a registered dietician who’s treated former F-Factor clients, said in an Instagram Story about the diet. “Your electrolytes, everything goes out of balance and can literally lead to a heart attack.” 

Zuckerbrot denied that any former clients had to go to the hospital for refeeding syndrome from following F-Factor, telling Betches that “refeeding syndrome occurs when a malnourished person begins feeding after a period of starvation or limited intake,” but “The F-Factor Diet is a nutrient-dense program that if followed correctly could never lead to malnourishment.”

Zuckerbrot told Insider that she had never been made aware of people who had developed eating disorders as a result of F-Factor. On the January 19th episode of the Diet Starts Tomorrow podcast, when asked, “does your diet create disordered eating habits?” Zuckerbrot responded, “I hope not.”

One DMer—in a screenshot available in Gellis’s Instagram highlights under the catch-all name “Discussions”—calls it “the devil’s food,” and another says the powders, bars, and GG crackers “literally destroyed [their] stomach.” Many people allege the products gave them rashes all over their bodies. (“It looked like someone drew on me with a red sharpie.”) Others say the diet instilled in them a lasting fear of fruit and carbs and other disordered eating habits even after quitting the regimen, and some are seeing gastroenterologists, worried about permanent gut damage. 

Another former client who wishes to remain anonymous told me she’s “85 percent sure” the diet permanently wrecked her metabolism and digestive system, even though she was only on it for two months. “I’ve become way more resistant to lactose than I was before, and I struggle to lose weight now even with diets I tried before, so I attribute it fully to F-Factor.” Zuckerbrot told Betches it is “medically impossible” for F-Factor to cause a lactose resistance, adding, “No diet can cause lactose intolerance as lactose intolerance is caused by a deficiency of the lactase enzyme.”

Another woman who was on the plan from 2017–2018 told me her hair was falling out in clumps while she did F-Factor, and she still feels the physical and mental effects to this day. “I still don’t go a day without counting the carbs I’m eating. I still feel like a failure sometimes for not being able to stick to a rigid, low-calorie plan. I know this is not how the diet is marketed, but this is the reality.” Zuckerbrot said F-Factor has never “received a formal complaint from a client that their hair was falling out in clumps as a result of the program,” acknowledging that one of the many causes of hair loss can be a Very Low Calorie Diet (VLCD), where calorie consumption is severely restricted—typically to under 1,000 calories per day. She said, “The F-Factor diet is not a VLCD.”

The woman also said her F-Factor dietician told her not to go to SoulCycle when she was on the diet because she’d “be too hungry after.” She said, “I was too afraid I would accidentally eat something off-plan if I went out with my friends, so I stayed in. I spent that whole year inside, and my entire value was tied to how much weight I lost that week.”

Zuckerbrot told Betches that while conversations between clients and Registered Dieticians are privileged, “it is not our philosophy to discourage anyone from exercising,” pointing to chapter 10 of the F-Factor book, entitled, “Exercise To Empty Your Glycogen Stores”, which is dedicated to the benefits of exercise.

Of course, the evidence of the diet having adverse effects is entirely anecdotal, so you can do with it what you will. If you’re an F-Factor stan and you have no reason to believe the products are harming you, there really isn’t any concrete evidence to suggest otherwise. 

However, there is one warning label on the F-Factor products. It’s a Prop 65 warning, which warns that consuming the product can lead to exposure to chemicals, including lead. Passed in California in 1986, the Proposition 65 law “requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects, or other reproductive harm.”

F-Factor claims their products comply with Prop 65, “the lowest lead standard in the world,” and Zuckerbrot denied that there’s a dangerous amount of lead in her products. In an IGTV video on her personal Instagram, she said, “the Earth’s soil contains heavy metal, and therefore anything grown in the soil—including strawberries, cucumbers, spinach, rice—can contain trace amounts.” She posited that F-Factor products may contain trace amounts of lead because they are made with all-natural products. She told Page Six, “In over two years we have received less than 50 complaints asking for refunds. This rumor that I somehow created a product that’s harming people’s health is so malicious and frankly unfounded,” and in a post on the F-Factor account said that any adverse physical reactions may have to do with a personal whey allergy. Zuckerbrot told Page Six she’s now working on a vegan protein powder for those who have a whey intolerance for this very reason.

Amidst the social media outcry, F-Factor critics were also urging the company to release its Certificate of Analysis (CoA), which is a company document for consumers that includes “specifications on characteristics such as purity, strength, composition, and appropriate limits for ingredients in which there is a known or reasonable expectation that a contaminant or adulterant may be present.” In response, F-Factor said they “view the CoA as a confidential document that contains proprietary information about our formula, and therefore, it is our company policy not to disclose this document.” 

One of Gellis’s followers said this is BS. “I work in biotech, and there is never a time, especially now pivoting to COVID diagnostics, that you don’t release a CoA. I would never work for a company that wouldn’t share these details, as they trickle down into everything.”

In a statement on the F-Factor Instagram account on August 22, the company said that “as a result of misinformation generated by a handful of people on social media,”  they’d release their CoA “within the next few days.” According to the statement, Zuckerbrot finds it “extraordinarily upsetting that some of you have been caused worry by false and malicious assertions, most of them made anonymously.” 

Finally, on August 28, F-Factor released the CoA for the chocolate fiber protein powder with “minimal information redacted”, again insisting it contains “proprietary information”. However, F-Factor also makes vanilla and unflavored powders, as well as a number of protein bars, for which the CoAs were not released.


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Even with the one CoA released, something tells me this is not the last we will be hearing about F-Factor or its founder.

Additional reporting by Sara Levine

Images: Fernando Leon/WireImage for Emily Cho; Nicholas Hunt/Getty Images; @f_factor / Instagram