1906.] Dr. R. Hutchison on Some Dietetic Problems. 269 



WEEKLY EVENING MEETING, 



Friday, March 9, 1906. 



His Grace the Duke of Northumberland, K.G. D.C.L. F.R.S., 

 President, in the Chair. 



Robert Hutchison, M.D. F.R.C.P. 



Some Dietetic Problems. 



The lecturer began by pointing out the great awakening of interest 

 in Dietetic Problems which had taken place in recent years, and which 

 had exhibited itself on the practical side in the promulgation of various 

 systems of diet, more or less heterodox, for which their advocates 

 claimed many advantages both economic and hygienic. With these 

 systems the lecturer did not propose to deal, but rather to make clear 

 the nature of the scientific problems which lie at the basis of the 

 whole subject, and to which answers must be furnished before any 

 acceptable system of practical dietetics could be formulated. In order 

 to approach the subject in the clearest way some elementary prelimi- 

 nary matters had first to be considered. The two functions of food 

 — (1) as a source of energy, and (2) as replacing waste — were there- 

 fore emphasized. Of the constituents of ordinary articles of food 

 the proteids, carbohydrates, fats, water and mineral matters, along 

 with gelatine and alcohol, were alone of nutritive value, and in con- 

 sidering subsequent problems the first five of those need alone be 

 taken into account. Emphasis was laid upon the fact that the pro- 

 teids, mineral matters and water are the nutritive ingredients which 

 are concerned in replacing waste, whilst the proteids, carbohydrates 

 and fats are the chief energy-yielding constituents of the food. 

 Reference w^as made to the large or kilo-calorie as the unit of energy 

 employed in dietetics, and the caloric value of some typical foods was 

 exhibited by the aid of a diagram. The lecturer then passed to the 

 first of the problems which had to be considered, viz. how much 

 energy (in calories) must the daily diet contain ? It was pointed out 

 that a reply to this question might be arrived at (1) scientifically, by 

 estimating the daily expenditure of energy in different forms by a 

 subject confined in a respiration-calorimeter, or (2) empirically, by 

 calculating the average amount of energy (in calories) contained in 

 the freely chosen diets of a number of individuals doing a moderate 

 amount of work and whose weight was stationary. In this way such 

 a balance sheet as the following could be constructed. 



