OPTIMUM LEVELS OF FAT 933 



There is available little information concerning the human requirement for fat. Fat 

 allowances mvist be based at present more on food halsits than on phj-siological require- 

 ments. ^Tiile a requirement for certain vuisaturated fatty acids (the linoleic and 

 arachidonic acids of natural fats) has been amply demonstrated with experimental ani- 

 mals, the human need for these fatt\^ acids is not known. In spite of the paucity of in- 

 formation on this subject there are several factors which make it desirable (1) that fat 

 be included in the diet to the e.xtent of at least 20 to 25% of the total Calories, and (2) 

 that the fat intake include essential imsaturated fattj" acids to the extent of at least 1% 

 of the total Calories. At higher levels of energ^^ expenditure, e.g. for a very active person 

 consuming 4500 Calories and for children and for adolescent persons, it is desirable that 

 30 to 35% of the total Calories be derived from fat. Since foodstuffs such as meat, 

 cheese, nuts, etc., contribute fat to the diet, it is necessary to use separated or "visible" 

 fats such as butter, oleomargarine, lard, or shortenings to supplj'^ only one-third to one- 

 half of the amounts indicated. 



Considerable experimental work is still required to determine what 

 quantities of fat are to be considered as optimal for man. It is evident that 

 the capacity to utilize dietary fat is limited and that, when large quantities 

 are consumed, gastrointestinal distress may follow. It is also of consider- 

 able importance to determine to what extent tolerance for fat varies with 

 the type of fat, as well as with the method of preparation of the food into 

 which fat is incorporated. 



