Stephanie Zerwas, the clinical director of the Center of Excellence for Eating Disorders at the University of North Carolina, was trying to find a restaurant in Orlando, Fla., last weekend, so she put the address into Google Maps for directions.

She was baffled to see a new feature: The iPhone app told her that walking instead of driving would burn 70 calories. While it was perhaps meant as an incentive to walk, those with eating disorders might instead fixate on the number, a dangerous mind-set that counselors try to minimize, she said.

“We’ve gotten into this habit of thinking about our bodies and the foods we take in and how much activity we do as this mathematical equation, and it’s really not,” she said. “The more we have technology that promotes that view, the more people who may develop eating disorders might be triggered into that pathway.”