In the case of the 12 normal men studied in the experiment of November 20 to 24, inclusive, extra foods were eaten away from the table (see table 32), but with Squads A and B no foods were consumed away from the table on the days with controlled diet. On the other hand, a regrettable feature in the study with Squad A was the desire of most of the men to chew gum excessively. For a few days gum-chewing was allowed ad libitum, but no record was made of the amounts used. Later it was recognized that an appreciable amount of energy was supplied by soluble carbohydrates in the gum. Thereafter records of the gum used were made for all of the men in both squads during the diet restriction.

A typical weekly gum record for Squads A and B is given in table 31. This shows that most of the men in both squads used rather large amounts of gum, although it so happens that one member of each squad took practically none (Pec in Squad A and Har in Squad B). The weekly gum record of a group of 12 men with uncontrolled diet was studied on November 20 to 24, the number of men studied apparently being sufficient to give a fair indication of the use of gum by the college body. Two or three of the men in this group were also members of Squad B. The amount of gum used was small as compared with the amounts given for Squads A and B in table 31, the total number of sticks per day for the 12 men for 5 consecutive days being 7, 7, 8, 0,. and 5. These small amounts led to an inspection of the gum record for all the members of Squad A, which revealed an increased use of gum as the restriction in diet continued. By analysis it was found that each stick of gum represents approximately 2 grams of soluble carbohydrates, or 8 calories. The use of gum must therefore be considered in a careful calculation of the energy in the diet.

Table 31. - Typical Week's Record Of Gum-Chemng Of Squads A And B

1 Subject Spe left the squad during the week here given. He had on the average 2 sticks of gumper day until November 8, after which his records repeatedly show days with no gum.

2 Har chewed but little gum; during January he had gum on only 6 days, with an average of about 2 sticks per day. 3Pec usually chewed no gum. On occasional days throughout the series he chewed 2 or 3 sticks;. on two days in October he chewed 5 sticks per day.

This intake of energy from the chewing of gum serves as another illustration of the subtle manner in which unidentified calories may creep into a supposedly controlled diet.1 The amount of extra foods consumed by the normal group of 12 men in the period of November 20 to 24 was very large, representing on the average not far from 5 per cent of the total nitrogen and, of still more significance, 10 per cent of the total calories ingested. (See table 32).

1Benedict and Benedict, Boston Med. and Surg. Journ., 1918, 179, p. 153.

Table 32. - Computed Nitrogen And Energy In Food Of Normal Group Of 12 Men, Nov. 20 To 24, 1917

[Values per man per day].