Abstract Metabolizable energy from the habitual diet was measured in lactating women from a Mexican rural community. Food intake was estimated in 12 women, age 25 ± 5 y, 2–6 m postpartum, body weight 48 ± 4 kg and height 147 ± 4 cm. Rural diet was predominantly from vegetable sources based on maize (tortillas), beans, tomato, onion and chili. The group was studied in free conditions with their habitual diet intake and in balance conditions consuming a controlled diet similar to their rural diet. Four women participated in a second balance with a modified diet, low in fiber and higher in protein and fat content in comparison with the habitual rural diet. Metabolizable energy was lower (P<0.05) by an average of 744 kJ/d in the rural diet than the modified diet. Apparent digestibility of energy increased from 82% and 87% with the free and controlled rural diets, respectively, to 93.4% with the modified diet. Digestibility for nitrogen and fat in the lactating women consuming the modified diet was higher (>22%) than with the rural diet. Metabolizable energy from the rural diet by the lactating women group was lower (8.1 MJ/d) than the energy recommended allowances during lactation. Nutrient digestibility from the rural diet was similar to those found in populations with intake of predominantly vegetable diets with high dietary fiber content.