Rich Bell literally made headlines when he started playing Pokémon Go. In a single month, the 29-year-old guessed, he lost 10 pounds chasing Zubats and Spearows.
In the weeks since, however, Bell has stopped playing - like many other early Pokémaniacs. He hasn't been walking as much; in fact, he thinks he may have gained some of his weight back.
Bell is not alone, incidentally: A new report from researchers at Microsoft found that Pokémon Go initially contributed to a major uptick in physical activity among its players, with possibly staggering public health effects. After downloading the game, the average highly engaged player increased his daily walks by 1,473 steps.
But one month after starting, the report found, those gains began to fade. Healthy or not, most players just . . . get sick of the game.
"I went hard for a couple of months or so, but it got boring after a while," Bell said. "I've caught almost every Pokémon that I can, visited most nearby places that were good for playing - just started getting repetitive."
The study, which is under review for journal publication, relied heavily on proprietary data from Microsoft, the company that funded the research. To reach their conclusions, the researchers combed through owners of the Microsoft Band, Microsoft's wearable fitness tracker, looking for people who had (a) opted into this sort of data collection and (b) recently searched Bing for terms related to Pokémon Go. From there, the researchers were able to compare the physical activity of 1,420 Microsoft Band users who played Pokémon with 50,000 who did not.
They observed a substantial increase in physical activity among players: on average, an extra 192 steps per day for each of the 30 days after they started playing. "Highly engaged" players, those who searched Bing for Pokémon Go terms repeatedly, increased their walks by even more steps: up to 1,473 extra steps daily.
Those gains were particularly pronounced among young and sedentary people, or those who walk less than 5,000 steps. After beginning the game, 32 percent of frequent players met the recommended average activity guideline of 8,000 daily steps - compared with 12.2 percent before they started playing, and 21 percent in the United States on average.
"Most surprising were the magnitude of the gains in physical activity and the significant benefits for low-activity populations," said Ryen White, the chief technology officer for health intelligence at Microsoft and a co-author of the study. "Novel mobile games like Pokémon Go have important public health implications, especially as a complement to existing physical activity interventions."
Unfortunately, there's a caveat, White and his co-authors explain. Pokémon Go "would have the potential to measurably affect U.S. life expectancy," they write - if high engagement could be sustained.
That doesn't appear to be the case, alas. An August report by the investment firm Axiom Capital Management suggested that the game's popularity peaked in mid-July and that engagement rates have since decreased steadily. More recent data from AppAnnie would appear to back that up: The game has fallen to 16th place in the App Store games category, from third a month ago.
That could be changed, White argues: It's just a matter of design. New sorts of challenges, and new variants in the game, could keep people playing - and walking - for longer periods. Maybe Pokémon Go could take a cue from augmented reality fitness apps, such as The Walk and Zombies, Run!, which use immersive stories to retain players' attention. Or maybe Niantic needs to tweak some of the features that make the game tedious in its middle stages.
Personally, Bell says, that could lure him back: He's looking forward to the rumored, upcoming release of "Pokémon Go: Generation 2."
"That'll probably get me back into it," he said. "At least for another month or two."
Caitlin Dewey is The Post's digital culture critic.
(c) 2016, The Washington Post · Caitlin Dewey