In order to feed our national hunger for nuggets and wings, a typical chicken is raised to weigh about 5 pounds. (The norm used to be more like 3.) Poultry isn’t the only thing that’s been supersized. Two slices of pizza have risen from 500 calories 20 years ago to about 850 calories today. Bagels have doubled in diameter in the same timeframe. And to accommodate all the extra food, your average dinner plate, at 12 inches across, is 30 percent bigger than one from the ‘50s.