Eighteen months after the Seattle law started, the caloric content start to drop. It fell by an average of 7 percent at sit-down restaurants, while the declines were smaller at fast food establishments. Notably, pizza restaurants were the only category of restaurants that showed no effect.
What accounted for the changes? Researchers chalk it up to two main factors: Portion sizes started getting smaller, and restaurants began substituting in lower-calorie ingredients.
That doesn't mean that people necessarily end up eating healthier: Research on how menu labels effect food consumption is mixed, with multiple studies finding such requirements have little to no impact.