• For space travel, the diet is carefully planned, but is associated with reduced appetite, negative energy and nitrogen balance.
• There is redistribution of fluids from the dependent tissues to equally over the body
• Bone readily demineralises
• Most of these changes return to normal on return to earth

Further Reading — 

Lane, H.W (1992) Nutrition in space: evidence from the US and the USSR.Nutrition Reviews, 50, 3–6.

Stein TP ( 2001) Nutrition in the space station era. Nutrition Research Review. 14, 87-117.