Like the "standard drinks" model for alcohol where we know how much our liver can metabolise in an hour, we should adopt a "standard meals" system to tackle obesity. Everyone's metabolism is different, yadda yadda, so is everyone's liver, but we still have that model, don't we? It should be easier than calorie-counting for fast food, and if we define 3 standard meals as how much one person should eat in one day, then printing "6.2 standard meals" beside some menu item would really make you stop to think. Based on a sub-standard Google Search, one standard meal should probably equal 500-600 calories.
Mokalus of Borg
PS - It may need a more complex definition than a calorie count.
PPS - But it's a place to start.