Grediagin, A., Smith, T., Lesher, S., Moynihan, S., Fulco, C., Friedlander, A., Cymerman, A., & Young, A. (2003). Nitrogen balance during energy deficit at altitude (4,300 m). Medicine and Science in Sports and Exercise, 35(5), Supplement abstract 1919.

For 7 days, men (N = 17) consumed a controlled protein diet sufficient to maintain weight at sea level. For 10 days at high altitude (4,300 m), the same diet was consumed.

At sea level, weight and nitrogen balance (an index of protein metabolism) changes were zero. At high altitude, Ss consumed less energy and protein but expended more energy and lost weight and protein. Protein loss was greater than predicted.

Implication. At high altitude, energy intake and expenditure does not match sea level habits. Protein is lost at an accelerated rate.

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