That is not entirely true: there are metabolic conditions which cause weight gain - hypothyroidism for instance.

It does not appear that Napoleon's eating habits changed a great deal but I do wonder about the exercise: I can't imagine the Imperial lifestyle involving more walking than was necessary to get round a large palace, he must have got most of his exercise on horseback in which case the horse was expending most of the calories. I get the impression that carriage driving was regarded as a form of exercise as well - it was probably pretty tiring when the roads were bad but it wouldn't have used a lot of calories.

Susan