American Journal of Clinical Nutrition, Vol 25, 67-73, Copyright © 1972 by The American Society for Clinical Nutrition, Inc.

Metabolic aspects of caloric restriction (420 kcal): body composition changes

¹ From the Bioenergetics Division, United States Army Medical Research and Nutrition Laboratory, Fitzsimons General Hospital, Denver, Colorado 80240 and the Department of Chemistry, University of Colorado

Body composition changes were observed in eight healthy adult males, 19 to 21 years of age, subsisting on a 420-kcal/day, all carbohydrate liquid diet, for 10 days. One-half of the subjects were denied essential mineral supplements (group I), and the remainder received the supplement (group II). The mean loss in body weight of 5.7 and 4.1 kg in groups I and II, respectively, was partitioned into the following losses in body compartments: group I, 1.24 kg fat and 4.47 kg fat-free body mass (including 0.90 kg dry protein); group II, 0.98 kg fat and 3.13 kg fat-free body mass (including 0.64 kg of dry protein).

The observed total body water (D₂O dilution) decreased significantly in both groups; however, a greater loss of water was observed in group I. Predicted body water estimates were lower than the observed values. Estimates of the dry protein mass derived from urinary creatinine excretion and total body potassium were higher than observed values.

Blood, plasma, and red cell volumes were significantly decreased in group I, whereas only blood and plasma volumes decreased in group II. Skin-fold thicknesses were decreased in both groups; however, those subjects of group II demonstrated lesser changes.