When is a 2,000-calorie meal fattening ? it depends on what time you eat it. Dr.Franz Halberg, a professor of laboratory medicine and pathology at the Universe of Minnesota, probed this mystery in a study conducted a few years ago.Each day for a week, he fed six volunteers a single meal,eaten at breakfast time,which consisted of 2,000 calories. Then he gave the same participants the identical 2,000-calorie meal as dinner for a week.But on the dinner regimen,four of the six people lost weight.Even the remaining two lost more on the breakfast diet than on the dinner diet. Dr.Halberg’s conclusion is that a calorie is not the same at breakfast as it is at dinner.