Canadian recommended nutrient intakes underestimate true energy requirements in middle-aged women

To examine whether Health Canada's Recommended Nutrient Intakes (RNI) and FAO/WHO/UNU (Food and Agriculture Organization, World Health Organization, United Nations University) values provide accurate indices of true energy requirements, energy expenditure was determined using doubly labelled water (DLW) over 13 days in a group of 29 middle-aged women. Energy intakes were calculated from weighed food intake, and energy expenditures and intakes were then compared with individual calculated RNI requirements. The mean energy requirement as determined by DLW expenditure (9.56 +/- 0.53 MJ/d) was higher (p < 0.0001) than reported energy intake (7.08 +/- 0.30 MJ/d) and was higher (p < 0.004) than RNI mean energy requirement (7.97 +/- 0.18 MJ/d). The mean RNI for energy was also lower (p < 0.0001) than that derived from FAO data. These results suggest that current Health Canada RNIs are inadequate in predicting the energy needs of Canadian middle-aged women.