Read This Before Trying an Intermittent Fasting App

When Katie Nunnally first heard about intermittent fasting she thought she’d found a diet that would mean minimal adjustments to how she ate. Having previously struggled with binge eating and trying to fit a healthy lifestyle around parenting duties, she hoped that restricting her eating hours might be the answer. But she soon found herself falling into old habits.

“For the first couple of days, it seemed really manageable,” the 36-year-old mother of two said said “However, I quickly became fixated on the end time of my eating window. Food became more of an obsession than it had been in years.”

Nunnally is far from the only follower of intermittent fasting (IF), a diet that encourages restricting eating to short time periods during the day. Earlier this year Twitter CEO Jack Dorsey caused a stir on his own site when he admitted to fasting for 22 hours a day, occasionally consuming only water for days on end.

Dorsey and many others have been attracted to IF as a type of biohacking, an ethos that applies a hacker’s mentality to manipulating one’s own biology. Advocates claim that fasting can boost productivity and aid weight loss, and for a trend firmly rooted in Silicon Valley it seems hardly surprising that there are a host of technological solutions that make the rules easier to follow. As the popularity of IF rises, so does the number of apps available to help users track and restrict their food intake.

Nunally used an app called Zero on the recommendation of friends, because the app's social aspect felt "like being part of a community of people using this eating plan,” she says. Others include MyFast, BodyFast, FastHabit, and more, which all include social-networking elements (comparing weight, goals, and time without food to your friends'), as well as streak tracking: noting just how long you've gone without food, often with congratulations or rewards for certain durations.

But in spite of the glossy, swipe-y, and even friendly user experience, these apps carry risks. Medical guidance states that skipping meals causes dizziness, irritability, headaches, and trouble concentrating. Other possible side effects include difficulty sleeping, daytime sleepiness, and dehydration. Although views on IF are mixed, the concerns that surround it are such that a rising number of medical professionals have begun to link its feast and fast mindset to that of diagnosable eating disorders, including anorexia and bulimia. A Harvard Medical School blog post on the subject posits that intermittent fasting — when combined with a healthy, balanced diet — can be an effective approach to weight loss (clarifying that limiting nighttime snacking and eating is pretty much the key to that), but it heavily caveats that the diet is unsafe for a number of people: those with diabetes, who are pregnant or breastfeeding, or anyone with a history of eating disorders such as anorexia and bulimia. A closer look at some IF apps makes it glaringly clear why that would be.

Zero is one of the most popular apps in this genre, allowing users to choose from a pre-programmed menu of fast styles: fasters can match their food-free period to their circadian rhythm; choose to fast for 18 hours and feast for six; or ramp up their fast to last 20 hours in a 24-hour period. One of Zero’s features is a live tally of the number of users currently successfully fasting. It is supposed to feel like being part of a movement. But for Nunally, it didn’t quite work that way.

“I became so focused on my own eating that I was forgetting to make real, healthy meals for my kids. My mind just ended up feeling so restricted that as soon as I gave myself the smallest space to enjoy a favorite food, I overindulged in a huge way. It really surprised me that intermittent fasting triggered those feelings of compulsive eating followed by the guilt that inevitably hits afterward.” According to NEDA, this behavior and the feelings associated it fit the criteria for binge eating disorder.

When opening the app you are encouraged to “Get ready to fast.” A clock reminds you of how long it has been since your last fast, and you can start a fast at the click of a button. A 20-hour fast seems to be the default, but users can navigate to a menu of even more extreme options. A so-called “monk fast” lasts a frightening 36 hours, and users can set custom fasts lasting up to seven days (there is no official medical guidance on how long it is safe to go without food; the general consensus is that eating regularly is a good thing). At the end of this food-free 168 hours users can be rewarded with a virtual burst of confetti exploding across their screen and a badge that is displayed to their friends in the app.

You can also share the results of your fast on social media, view your complete fasting “journey,” and read hand-picked articles in support of IF. The app doesn’t seem to include any information on the possible risks of restrictive eating and, unlike calorie counting apps like MyFitnessPal, which have introduced health warnings, Zero congratulated me when I accidentally left a fast running, supposedly forgoing food for a surely red-flag-raising 493 hours — more than 20 days.

Being able to celebrate long periods of starvation, and even compare them with fellow fasters (a feature available in several IF apps), may seem in keeping with our data-driven times. After all, many of us are metrics-minded, tracking everything from our daily steps to our screen time, constantly keyed in to social media to share updates about our morning coffee, evening workout, and everything in between. Yet for Chloe*, 23, a personal trainer who has been in recovery from an eating disorder for several years, the sense of being rewarded for going long periods without food felt all too familiar.

“Intermittent fasting apps remind me of the eating disorder mentality of competitively not eating,” she says. “When I was in the grips of my disorder I would often visit pro-anorexia forums where users would compare how little we had managed to eat. The design of some IF apps seems a little too similar.”

Chloe decided to try IF when she heard a buzz around its benefits from other personal trainers at the gym where she worked. Although she used her phone to track plenty of other aspects of her fitness routine and lifestyle, she soon found the IF apps to have troubling psychological effects.

“I’m always on my phone so downloading an app to regulate my IF routine seemed like the natural thing to do,” she explained. “Unfortunately I found the app extremely triggering and quickly became fixated on how long I could go without food. I went from fasting for 16 hours to fasting for 20 hours within days. The thought-pattern of seeing how far I could push my body felt very similar to how I’d approached my eating disorder in the past.”

It seems that for individuals like Jack Dorsey — male, highly successful, and deep in Silicon Valley — it is possible to disguise disordered eating with the buzzwords of wellness and biohacking. Yet simply technologizing starvation shouldn’t make it socially acceptable. Would a female celebrity professing to eat only one meal a day be seen in the same light, or would she be more quickly accused of suffering from an eating disorder — even proselytizing one. Certainly for Chloe, IF became disordered eating by another name.

“Nobody starts intermittent fasting setting out to have a disordered eating pattern, however, I think if you are constantly restricting yourself to a certain pattern or food group it can become something you obsess over,” explains Aishah Muhammad, M.D., a doctor and certified personal trainer who offers weightloss coaching. “When we are not listening to our body's cues and giving it what it needs, we are crossing the fine line between using new ideas to be healthy, and doing ourselves harm.”

Intermittent fasting apps have repackaged the desire for physical and mental perfection into a biohacking solution with a tech CEO’s cosign. By aligning our food intake with technology they at first seem to transcend the tired world of calorie-counting and restricting certain food groups (increasingly unfashionable in an age of body-positivity and the strong-not-skinny movement). Yet the connotations are fundamentally the same.

“When using an app [to track diet], I feel like we give control over to a device,” says Dr. Muhammad. “This can have horrible psychological effects and can lead to a person having a distorted relationship with their food. Physical hunger sensations are there for a reason, so if you want to use apps to help you on your IF journey, keep the control in your hand. Don’t become obsessed with numbers. Do your own research and if you are confused speak to a registered nutritionist, dietician or physician for advice.”

When it comes to biological cues such as hunger Dr. Muhammad makes a pertinent point. If we allow an app to tell us when we can and can’t eat, we abandon all of the ready-made tools that our body has on board. Hunger and intuition are, after all, inbuilt for survival. If you begin feeling hungry just as your phone reminds you to skip breakfast — which notification do you ignore?

*Name has been changed.

If you are struggling with disordered eating, contact the NEDA helpline for free online support or by calling (800) 931-2237.