The author's purpose was to compare through twenty centuries expenditure of energy in raman legionnaires and its alimentary covering with those observed nowadays amidst soldiers and sportsmen. Daily expenditure of energy can be estimated at 5000 kcal for the legionnaire performing engineer work and at 6000 kcal when he was in war action. Every man was given daily by the supply corps: 1 kg of wheat, 100 g of bacon, 30 g of cheese, for a total around of 3500 kcal. This ration was planned to cover basic needs. The search for complements was left to the legionnaire's initiative. Nowadays, only workmen and sportsmen reach such a level of energy expenditure. Unless completed by an exogenous supply, legionnaire's daily ration was unbalanced, with 78% carbohydrates. On the other hand, it had the advantage of providing slow carbohydrates, of being highly energizing and easily digestible. It provided a good intestinal ballast and was fairly fitted to restore the energetic reserves of the organism. Due both to intuition and to necessity, the essential needs were covered. But, at a long time range, legionnaires were hazarding deficiency.