Two papers were presented on energy expenditures of women living under their usual conditions (papers 19, 20). McGuire and Torun prospectively studied, for one year, a group of Guatemalan rural women who were engaged in various activities. Observations were conducted on eight who became pregnant and on fifteen lactating women during the study period. DeGuzman's female subjects were Philippine housewives and peasant women; pregnant and lactating women were not included in her studies. The mean age, body weight, and height were comparable for both studies. The studies included measurements of food intake, specific energy expenditure and time spent in each activity. Indirect calorimetry was used in both studies to determine the energy cost per unit of time. For basic activities like standing, sitting, and walking, comparable values were obtained in both the studies, and they were 0.024, 0.023, 0.046/kcal, and 0.021, 0.022, 0.0500 per kg per minute for Philippine and Guatemalan women, respectively. The values for other tasks performed varied between the two studies, depending on the type of work and manner in which the activities were performed.
The overall daily energy intake for the Guatemalan female subjects was 1792 ± 492 Kcal. However, energy expenditure was 1985 ± 483 Kcal per day. The observed daily energy intakes for the women studied by DeGuzman was 1785± 553Kcal, while the estimated daily expenditure of these subjects was 2040 ± 328 Kcal.
The mean energy intake for pregnant and lactating Guatemalan women were stated to be 1678 ± 558 Kcal, and 1845 ± 483 Kcal per day, respectively. The mean energy expenditures of the pregnant and lactating women were estimated to be 2044 ± 167 Kcal and 1981 ± 160 Kcal per day.
Both studies clearly show that, using available energy balance methodology, there is a significant energy gap for these working women. Torun's study indicates that the pregnant women are in an even more marked negative energy balance. It is evident that further research is necessary to assess the current energy requirement for the working woman, especially during lactation and pregnancy, and more knowledge is needed on the possible changes of energy efficiency in populations that appear to be in negative balance.
An additional paper by Ho (paper 21) provided comparable information on the energy expenditure of peasant women in Southern China, as well as that of miners and shipbuilders doing variable types of work in their respective occupations.
The limitations of indirect calorimetry to assess energy expenditure properly were discussed, and the need to obtain data using newly developed direct calorimeters was expressed.
