Elemental balances in obese women fed a hypocaloric dietary regimen

Abstract

Nine moderately obese college women were fed unrestricted, self-selected diets for eight days followed by 37 days of moderately restricted caloric intake which met most recommended dietary allowances. Ingesta and excreta were collected during three seven-day intervals and were analyzed for potassium, magnesium, zinc, copper, and nitrogen. During the unrestricted interval, mean apparent retention of each element was slightly positive. Mean apparent retention of nitrogen, copper and magnesium remained near zero during the restricted intervals. Although potassium intakes were within recommended range, mean apparent retention of potassium became negative during restricted intervals. Mean urinary potassium was significantly greater during the fifth week of restriction than during the unrestricted interval. Mean zinc intake decreased and excretion increased significantly during restriction such that mean zinc retention was apprecably negative by week five. Throughout the study, there was no significant change in mean urinary nitrogen or creatinine, suggesting that lean body mass did not change. Mean weight loss was 7.01 kg. In summary, body potassium and zinc seemed to be preferentially depleted under dietary conditions which promoted nitrogen balance and moderate weight loss.