Amazon Halo’s Body Scan Feature Isn’t Just Dangerous — It’s Also Potentially Useless

The feature uses photos to track body fat percentage and to create a 3D model of your body

Photo: Amazon

The moment Amazon announced its first fitness band, the $99 Amazon Halo, my social feeds lit up with bafflement and concern over its emotion-detecting software, which listens to your speech to discern your mood. While tracking voice tone is certainly strange, I was immediately far more concerned about the Halo’s body-scanning feature. The feature requires users to take several photos of their body from different angles with their smartphone, which the app then analyzes for body fat percentage. The app also creates a 3D model of the user’s body, on which they can move a slider to see how their body would look with more or less body fat.

Though my struggles with disordered eating and body image are relatively minor compared to what a lot of people have to deal with, and I’ve come a long way, this feature makes me extremely uncomfortable. I already have a bad habit of looking at old images of myself and comparing my current weight to when I was lighter or heavier; the thought of having artificial intelligence make a 3D mockup of my body minus five body fat percentage points would be detrimental to my mental health. If this product had come out when I was 17, or even 22, it may have been disastrous.

It’s difficult to imagine a feature that could be more painful to people at risk of developing or already living with eating disorders or body image issues. Even if you don’t have such issues, the feature still has significant drawbacks — namely, there’s little proof that it’ll help you live healthier.

“In terms of who this could be helpful for, I’m not entirely sure.”

There is evidence that for people who want to lose weight and don’t have acute body image issues, tracking their weight on a regular basis — aka, one of the basic functionalities available on nearly every fitness tracker on the market — helps them lose weight and keep it off. But there’s far less evidence indicating the same for tracking body fat percentage, which is a newer, far less understood metric. I couldn’t find any studies showing that seeing a 3D image of yourself as thinner or fatter is compelling, helpful information. Amazon told The Verge it did an internal study verifying the credibility of its methods and may submit research for peer review in the future.

“I think such an app could be particularly harmful for those who are at high risk for an eating disorder (e.g., already have very high concerns about their weight/shape) or have other vulnerabilities for such concerns (e.g., family history of eating disorders, high perfectionism, etc.),” says Ellen E. Fitzsimmons-Craft, PhD, an assistant professor of psychiatry at Washington University’s Center for Healthy Weight and Wellness in St. Louis. “In terms of who this could be helpful for, I’m not entirely sure as I am not clear that this information is particularly needed or necessary for the average individual to have on such a regular basis.” Knowing your body fat percentage would be just another metric to obsess over, she says.

It’s worth noting that the Halo does offer app features to reduce that kind of obsession. For one, it analyzes activity on a weekly rather than daily basis, encouraging users to focus more on their overall activity level rather than drilling down into the details of daily movement. This doesn’t mean motivated users won’t look at the data every day or throughout the day anyway, but the Halo won’t be fostering that kind of behavior. It also doesn’t allow the body fat slider to go below an “unhealthy” level (though Amazon hasn’t defined what that means). Amazon doesn’t recommend its product for pregnant women, and there are age limits: Anyone over the age of 13 can use the band, but the body-scanning feature, specifically, is limited to those over the age of 18.

This age restriction is smart — research shows that people are most at risk of developing eating disorders and body image issues when they’re in their teens. “The high-risk age group for eating disorders is sort of that early teens right up into sort of young adulthood,” says Elizabeth Evans, PhD, a lecturer in psychology at Newcastle University in England whose research focuses on weight management and body image. “It sounds like they’re thinking about the body image implications, and they’re also saying that you can’t use the body imaging software if you’re below 18. And all I can say about that is my 11-year-old writes three programming languages, and I wouldn’t know what the hell she was doing to my computer.” Anyone with kids knows how hard it is to keep them away from something they want to access — if a 14-year-old wants to use the body fat scanner and slider, they’ll find a way.

The risk of a kid scanning their body and finding out how they’d look if they lost 2% of their body fat might seem like a decent trade to make if there were clear advantages for most users. After all, we have all sorts of things in society that are incredibly dangerous for children to use — cars, for example, or butcher knives — but the benefit of quickly moving from point A to point B or effectively carving up a large pork shoulder make it worth the risk. That doesn’t seem to be the case with the Halo’s body-scanning feature.

For teens and college students who are at a particular risk of developing body image issues or eating disorders, it can be dangerous to have access to this information without context on what it means.

Part of the problem is that Amazon claims its body scanner is “as accurate as methods a doctor would use and nearly twice as accurate as leading at-home smart scales.” In its press release, Amazon goes on to say that the scan you can get in a doctor’s office is expensive and requires a prescription, insinuating that the reading provided by the Halo is as good while being much more accessible. But compared to weight or body mass index (both of which are, to be clear, imperfect ways to calculate someone’s health), body fat percentage is not well understood by the public. For users to truly understand what it means to have 36% body fat, they’d need to discuss it with a doctor. Getting that information from the Halo means users are left to their own devices, so to speak. In a culture in which weight stigma, body dysmorphia, and eating disorders are disturbingly common, it’s highly likely that information will be useless at best and damaging at worst.

“We know a lot about body fat index or body fat percentage and its relationship to health, but we don’t know enough about it to start communicating with the bloody public about it,” says Evans. “BMI might be rubbish. However, it is understood. Its limitations and its rubbishness are well characterized, and we use BMI with a pinch of salt. That’s how it’s meant to be used. We don’t know how to use the body fat percentage with a pinch of salt yet.”

Michelle Cardel, PhD, an obesity and nutrition scientist at the University of Florida, agrees that for the safest results, information like body fat percentage should be discussed with a professional. “I am always a little concerned about the emphasis on weight in some of these more scalable disseminated programs or resources. Because I think it’s always better if they’re done in conjunction with medical supervision and somebody to debrief what these numbers actually mean for you,” she says. “In the case of body fat percentage, lower does not always mean better … without any sort of supervision, people can sometimes take that approach of less is better” whether or not that’s the case. Cardel points out that when you get your blood drawn, you’re typically not left to figure out what it means that you have, say, low iron levels. Why should body fat be any different?

For teens and college students who are at a particular risk of developing body image issues or eating disorders, it can be dangerous to have access to this information without context on what it means. Instead, the device provides them with a slider to see how they’d look with more or less body fat.

Evans points out that studies that investigate how images of thin people affect participants show that it’s primarily people who are already at risk, such as people with body dissatisfaction and symptoms of eating disorders, who come away from the study worse off. “The very people who you really don’t want having access to [this information] are most damaged by it. Moreover, those individuals are more likely to seek it out than the general member of the public,” she says. These studies typically investigate how images of others, such as celebrities, affect people; such images are less damaging than modified images of themselves because people are able to build boundaries and understand that they’re not a celebrity or a model.

Things get messier (and more dangerous) when the participant is presented with a “better” image of themselves. One 2015 study found that teen girls who frequently edit or filter their selfies are more likely to experience body- and eating-related concerns than those who didn’t and that the impact may be bidirectional: Those who are already stressed about their body are more likely to edit their photos, and in turn, the editing of those photos may reinforce the body image stress.

“There’s really good evidence that people seem to be sustaining negative effects from that kind of process, particularly if they’re then putting themselves out there for self-evaluation” by sharing the image on social media, says Evans. “So how does that relate to Halo? Because it’s personalized, because it’s your body on that screen, there’s no way to build a wall between yourself and the image that is self-protective,” which is what people do when they’re looking at images of skinny celebrities in magazines. And if those images are already damaging for people who are at risk, how much worse will a 3D body scan of a self that has 5% less body fat be?

Cardel says the product could be safer for at-risk users if Amazon implemented a number of features, such as an alert that appears if users try to slide their body fat to a dangerously low level or if they had a quiz that asks users if they’ve ever struggled with body image or eating disorders before. If so, the body scanner would be disabled for those users. Amazon told me it plans to highlight the risks of extremely low body fat in the app, but it’s unclear how it plans to display that information.

Since the product offers little tangible benefit for even its psychologically healthy users, if Amazon wants to protect its most vulnerable users (and that is a significant number of Americans), it could eliminate the body scanning function of the Halo altogether. There’s simply no reason for it to exist until we have a clearer understanding of what it offers and how that stacks up against the hazards it presents.

I’m a columnist for OneZero, where I write about the intersection of health & tech. Also seen at Elemental, The Atlantic, VICE, and Vox. Brooklyn, NY.

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