264 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



CONCLUSIONS REGARDING EFFECT OF INGESTION OF FAT. 



Although the experiments in this series can hardly be considered as 

 ideal, being open to the criticisms raised in their discussion, yet the 

 preponderance of evidence clearly shows that the ingestion of fat in 

 the form of cream, or butter with potato chips, has a positive influence 

 upon the metabolism. This is not in accordance with the results of 

 Koraen, 1 who found no increase in the metabolism after the ingestion 

 of about 66 grams of fat. Aside from a few experiments in which a 

 depression in the metabolism below the basal value was found in the 

 latter part of the experimental period, we obtained no evidence sup- 

 porting the general view of Gigon that the ingestion of fat results in a 

 depression of the metabolism (see page 40). Gigon's most interesting 

 and suggestive explanation of his experiments, namely, that the inges- 

 tion of a fat diet (olive oil) caused a depression of the digestive activity 

 which is present even in the post-absorptive condition, finds no sup- 

 port in the results of our experiments. It should be borne in mind 

 that Gigon used a pure fat, while all of our experiments were carried 

 out with materials containing a certain proportion of other nutrients. 

 It is difficult, however, to believe that the starch in the potato chips 

 or the small amount of protein and lactose in the cream could have 

 counterbalanced the effect observed by Gigon. We are inclined to 

 consider that the depression in the metabolism reported by him was 

 more apparent than real and that his findings are due to the faulty 

 use of a basal value, determined a long time before the experiments 

 were made. By the use of this value he assumed a constancy in basal 

 metabolism which, while justifiable when severe muscular work is to 

 be performed, is hardly permissible when small increments in the 

 metabolism are to be expected, such as those following the ingestion of 

 small amounts of food or even large amounts of fat. 2 



We may therefore conclude that the ingestion of fat produces a 

 positive increment in the metabolism. Although the increment is 

 considerably less than that observed with an equivalent amount of 

 energy in either carbohydrate or protein, it is nevertheless a factor 

 that must not be neglected in a consideration of the influence of the 

 ingestion of food upon the metabolism. We are in full accord with 

 Gigon in believing that a study of the effect on the metabolism of 

 ingesting pure fat is highly desirable and regret that more experiments 

 with olive oil or other pure fats were not included in our series. 



Koraen, Skand. Arch. f. Physiol., 1901, 11, p. 176. See, also, p. 32 of this publication. 



2 Personal acquaintance with Professor Gigon and a full appreciation of his high scientific con- 

 ceptions of the importance of physiological research have led us to attempt to communicate with 

 him personally regarding the adverse criticisms which we have felt it necessary to make in this 

 report. While an acknowledgment of the receipt of the letter has been made, he states that it 

 has been impossible for him as yet to take up in detail any of the criticisms which we raise, although 

 he promises to send a letter to us shortly. Undoubtedly war conditions have made it impracti- 

 cable for him to do this. It is a matter of great regret to us that we have been obliged to go to 

 press without personal information regarding the criticisms here raised, so that if we are in error 

 or have misinterpreted his attitude wo might modify our expressions in such way as to fit the case 

 more exactly. 



