It's not the carbs, it's the calories. The government is releasing dietary guidelines today that call on Americans to exercise more, and eat better. The Agriculture Department is revising its food pyramid to reflect a call for more whole grains instead of refined ones, and eating a lot more vegetables and fruit. An advisory committee found people leading sedentary lifestyles and choosing their food poorly. Many are eating more calories than they need and still aren't getting enough nutrition. The panel says controlling calories -- not limiting carbohydrates, as some popular diets recommend -- is key to controlling weight. Daily exercise is also important.