WASHINGTON - First Lady Michelle Obama may have temporarily forgotten the lessons of her own anti-obesity campaign when she indulged in a sinfully caloric lunch Monday at a popular new hamburger restaurant. A Washington Post reporter said the first lady ordered a cheeseburger, french fries, chocolate shake and Diet Coke at Shake Shack -- a trendy hamburger spot that recently opened an outpost in Washington's Dupont Circle. Based on nutritional information on the restaurant's website, the meal added up to a scale-tipping 1,556 calories.