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Observations in energy and macronutrient intake during prolonged bed-rest in a head-down tilt position
1Centre de Recherche en Nutrition Humaine, Clermont-Ferrand Cedex 1, 63009, France.
Objective:
to report observations in energy and macronutrient intakes, and body weight during prolonged bed-rest in a head down tilt (HDT) position.
Design:
open study, each subject was his own control, and was studied during 14 days of baseline, 42 days of -6 degrees HDT bed-rest, and 12 days of recovery.
Subjects:
eight healthy young man were recruited, one dropped out.
Methods:
energy and macronutrient content of the diet were calculated from weighed amounts of food consumed and French food composition tables.
Results:
body weight declined during HDT (74.0+/-3.2 to 71.8+/-3.2 kg, P<< 0.001) and increased during recovery (72.7+/-3.2 kg, P<< 0. 001). Energy intake decreased during HDT (by 17% after 4-5 weeks) and increased during recovery but remained lower than during baseline (P<< 0.001). During HDT fat intake, expressed by a percentage of energy, decreased (P<< 0.01) while carbohydrate increased (P= 0.04); protein intake did not change (P= 0.08). The reverse trends were observed during recovery.
Conclusions:
the present study reports a spontaneous reduction in energy and relative fat intake during prolonged HDT bed rest. We believe that these findings have implications for the clinical setting.