A chart showing graphically the respiratory quotient and the percentage of calories furnished by protein,fat and carbohydrate.

The percentages of calories furnished by the various foodstuffs can be shown graphically and with satisfactory accuracy on a chart which is almost an equilateral triangle. The base represents the respiratory quotient. The lower left hand corner (R. Q. 0.707) represents the theoretical point at which 100 per cent of the calories are obtained from fat, the lower right corner (R. Q. 1.00) represents 100 per cent of the calories from carbohydrate. The top of the triangle, which is over the R.Q. of 0.801 is the protein corner. The percentage of calories furnished by protein is shown by means of lines almost parallel to the base. The percentage furnished by carbohydrate is shown by lines parallel to the left side of the triangle. These parallel lines are almost but not quite equidistant.

Almost all the phenomena of the respiratory metabolism can be represented graphically on this “metabolism map” and we can follow the changes which result from the ingestion of protein or carbohydrate. In the lower left hand corner is the zone of ketosis. Outside and to the left of the triangle is the zone in which protein is partially converted into carbohydrate. To the right of the triangle is the zone in which carbohydrate is converted into fat.