The figure of 4500 calories usually quoted for the naval diet appears to be derived from a chart which is seriously flawed in several respects: first by reading ‘bisket’ as ‘brisket’ in the document from which the list of food was taken (the difference in calories per 100g between the two foodstuffs being 290 calories), secondly by faulty conversions from eighteenth-century weights to grams/millilitres, and thirdly for several inaccurate calorie-counts.1
A more accurate calculation is as follows:2
As can be seen from the notes, it is difficult to be exact on some items, since the modern calorie counts are calculated on modern types of beer and specific cuts of meat; the Georgian sailor could not know which cut of meat he was going to get until it arrived on his plate.
However, even as calculated, the amounts of total calories issued is still subject to many possible variations, not least of these being the official recommendation that on one day each week, the issue of beef should be replaced with 1½ lbs of flour and ½ lb of raisins. This substitution alone would bring the weekly ration up to 35,560 calories, and thus a daily average of 5080. Substitute suet for the raisins and the daily average goes up to 5134. The following table gives the calorie counts of the other types of food and drink used as substitutes. Note that there is a considerable difference between beer, wine and spirits; a man on red wine receives 624 calories less per day, one on spirits 420 less per day than those on beer.
