In high school, I didn’t have a scale in my house, but my friend Eliza did. A typical Saturday night for us was to eat a bunch of cookie dough and then marathon a season of Friends. When I used the bathroom at her house, I couldn’t help but step on the scale. As soon as it registered my weight, I’d realize my horrible mistake of ever going near sugar, and then return to the TV den and insist on doing crunches, as though I could remove all the fat I didn’t want right then and there, while three women of varying degrees of “extremely skinny” engaged in hijinks on screen.
“The scale is bad news,” says Dan Ariely, a behavioral economist at Duke University. Weight fluctuates naturally, and people are just not good at taking the data a scale provides and using it to make rational choices.
Say one day you exercise a lot, and then the scale declares that you’ve gained half a pound. Feels bad, right? For all the overwhelming guilt or grim success a single measurement can make someone feel, each individual weigh-in is just not that meaningful—carb intake, water retention, hormone levels, and even the amount of sleep you get can affect your day-to-day weight by as much as a few pounds.
Ariely’s proposed solution is the Shapa (“shape-ah”), a scale without numbers. It looks like a small flying saucer, and in lieu of showing your weight in pounds or kilos, it has a glowing S in the middle that lights up in a color corresponding to how your weight is trending relative to the past three weeks, from gray to green to blue.
Ahead of the Shapa’s release in December, I was able to try one out. I installed the accompanying app on my phone, answered dozens of questions about my habits, and began stepping on the Shapa twice a day, as the app mandates.
Ariely’s inclinations to bring the focus away from individual data points track with my own experience learning to be dispassionate about my literal weight. My obsession with scales took off in college. I was bad at feeding myself regular meals, so I’d often have the majority of calories for the day in, say, a single pint of Ben & Jerry’s, always unable to stop until I finished the whole thing. The next day, I’d go to the YMCA, get on the scale—I knew enough to keep the thing out of my own home—and notice either a small dip in weight (and feel relief) or a jump in weight (and feel terrible). I’d exercise and then get back on the scale again a whopping hour later to assess my “progress.”
The other problem is that I hated my weight. When my therapist suggested I had habits and accompanying thought patterns that represented disordered eating (I never threw up after binging, but not for lack of trying), I felt heard and relieved. She signed me up for group therapy, a weekly session with a dietician, and a regular appointment with a scale in her office.
My obsession with scales took off in college.
The idea with that scale was for me to learn to treat my weight like any other metric about myself, such as my height or age. (The concept that one’s weight stays within a general range despite even solid efforts to change it is called set-point theory [PDF].) My therapist kept a log of my weight with a little arrow or dash next to each number: up, down, up, up, up, down, the same. And so on. We’d start the session off talking about how it made me feel. At first: “Bad.” “Triumphant.” “Triumphant.” “Meh.” “Bad.” But then: “I don’t know, we’ve been doing this for weeks, I am kind of used to it?” I even learned not to hate the underlying number—about 160 pounds—itself.
Last spring I set up a line of scales in my bathroom to test for Wirecutter’s guide. My roommate came home to find me marching on and off them. “I’m bored!” I declared. Once, it would have felt like walking a tightrope.
While the Shapa does away with weight in numbers, the goal is decidedly not dispassion toward weight as a concept. Ariely made the scale to address obesity, and he has measured its success in pounds lost. In a 12-week pilot study with 645 participants, Ariely found that participants who used the Shapa (app and all) lost on average 0.61 percent of their weight per month (for a 200-pound person, that’s 1.2 pounds for the first month), while the group of regular numerical-scale users gained 0.91 percent. (Treat these numbers lightly: The study was not peer reviewed.) For rough comparison, in a study on (and also funded and designed by) Weight Watchers, participants lost about 2 pounds a month for three months using the online program.
However, the Shapa is far more expensive than other scale options. It costs $130 for the physical device, plus $10 a month for the subscription accompanying the app; for comparison, our top smart-scale pick, the Eufy BodySense, typically costs $50. That Eufy model charts out your body weight on a graph so you can see the overall trend and choose to respond to that rather than the number on any given day. (That concept is admittedly trickier than having the Shapa mask the figures for you.) The Shapa system is more comparable to something like Weight Watchers, which costs about $20 per month for a basic online subscription, or about the same for one year once you factor in the price of the Shapa scale. (Due to overwhelming demand from participants in a pilot study, a future version of the Shapa will have the numerical weight buried somewhere in its app.)
If you’re committed to using the Shapa scale as part of a weight-loss program, it sends reminders. When I was about to miss a weigh in, the Shapa app sent a notification congratulating me on my streak so far and encouraging me to keep it up. I haven’t seen anything else that will do the same thing (as seamlessly with the scale, at least—it’s easy to set up a daily reminder on your phone’s calendar and track your habit with a free app).
Part of the way the Shapa system justifies its subscription cost is through a barrage of general health tips and push notifications from its app. The Shapa app gave me daily missions to help me eat less—such as to drink more water, or use smaller plates at mealtimes—or to simply continue engaging with the app and my ostensible goal of losing weight, like decluttering my room or sending a silly selfie to a friend. I lied and told the Shapa app that I decluttered my room, and it sent me a notification: “You are terrific” followed by a heart-eyes emoji.
The app’s daily missions are not that beneficial, per Ariely’s study: Participants who used the Shapa scale without them lost an average of 0.57 percent of their weight per month, essentially the same amount as the group that did receive them.
While the notion of using smart features to focus on the value of body weight as a trend is a promising application of tech, the Shapa is still narrowly focused on the concept of losing weight, which cuts out potential owners who may want to maintain weight or even gain it. (The Shapa website currently suggests that the scale can accommodate all kinds of health goals, but the actual system accommodates only weight-loss goals for now.) For those people, the daily missions and reminders might even be counterproductive. Focusing singularly on weight as a metric of health isn’t the best route even for obese people; losing weight and keeping it off can be monumentally challenging, and ultimately not as connected to healthy behaviors, even in the long term, as people might like. If someone—no matter their size—has perfected their diet and exercise routine to the point that they feel healthy, but they then see a light telling them to try harder when they weigh in, it might be discouraging. Likewise, someone could tumble down a rabbit hole of restrictive eating and exercise, cheered on by a blue light from the Shapa; being overweight by BMI standards doesn’t preclude a person from developing an eating disorder.
This problem is hardly unique to the Shapa. Even the best smart scales fail to give owners the ability to set—and be supported by—their own goals. For instance, you have no way to prevent the Eufy BodySense from displaying that your weight is “normal,” “high,” or “excessive” based on your BMI, regardless of how the number fits into your overall health. Even with expanded goals, the Shapa won’t be for everyone: Ultimately, the whole thing is about controlling your body, not observing it for what it is.
Ariely knows weight isn’t the be-all and end-all, and he has ambitions to expand the approach to other devices and metrics of health, including blood pressure and cholesterol. And his scale seems to be evolving on the issue, too: In a version of the app that I tried prior to the scale’s launch, a bright green light from the scale indicated weight loss. Now, green corresponds with no change in weight. “Shapa is celebrating for the users even if they are just maintaining their weight,” explain the press materials.
As it is, the Shapa is too narrowly focused to be useful for anyone who isn’t trying to lose weight, and it’s possibly damaging to anyone who has anxieties about their weight. Even if it weren’t, a subscription would be hard to justify. On top of that, the Shapa scale takes three weeks of twice-daily weigh-ins to calibrate to your weight. After weeks and many weigh-ins, I still failed to use the Shapa consistently enough to even calibrate it. Even though the current device misses the mark, Ariely is on to something in making tech that looks beyond the fine-grained data toward something more meaningful.