Most people have a pretty good idea of what it means to eat healthy foods, but few manage to do it. A new app called the Eatery aims to change that by having users rate one another's meals and providing slick data visualizations of a person's habits over time. The app's users have rated more than two million meals so far. When overlaid on maps, this data reveals patterns in healthy eating in cities like New York and San Francisco.Eatery users snap a photo of a meal, and that photo is automatically tagged for location. After users take a photo of a meal, they are prompted to quickly rate the healthfulness of other users' meals by looking at their photos, in a quick process intended to be fun. This process ensures that each user's meals are rated by other Eatery users.The app uses those meal ratings to provide users with statistics, including changes from week to week in what they ate, the places where they ate the most healthy and least healthy meals, and their best and worst meals of the week.See images from the Eatery on the following pages.