Two village populations, Kaul in a coastal region and Lufa in a highland region, were studied each for 9-10 months. Measurements of food intake and total daily energy expenditure were made on individual subjects, 51 men and 69 women in Kaul and 43 men and 41 women in Lufa. Each individual was investigated during a period of 5-7 consecutive days. The way of life for all the people was moderately active - more so in the highlands - since they were subsistence farmers cultivating their own gardens for food. The mean daily energy intakes were 8.12 MJ (1940 kcal) for the Kaul men, 10.55 MJ (2520 kcal) for the Lufa men, 5.95 MJ (1420 kcal) for the Kaul women and 8.81 MJ (2105 kcal) for the Lufa women. There were almost no differences in the energy intakes of the non-pregnant non-lactating, the pregnant, and the lactating women in each village. The intakes of protein were low, providing 6.7, 6.0, 6.5 and 7.2% of the energy value of the diets of the Kaul men and women and the Lufa men and women respectively. Fat provided only about 10% of the energy in the highland diet and 17% in the coastal diet. Age and body mass showed surprising relationships with energy intake. Although most of the energy and protein in the diets came from the staple vegetable (taroin Kaul and sweet potato in Lufa), this was less so than in previous studies. A total of 1160 measurements of energy expenditure were made on various activities of the individual people and mean values are given for these activities. The pattern of daily energy expenditure is also shown. Lying, sitting and standing accounted for about 70% of the total day and 60% of the total energy expenditure. Walking occupied about 10% of the 24 h and between 20 and 27% of the energy output. Some of the results of food intake, particularly on the women in the coastal region, are very difficult to explain on currently accepted grounds.