King Grub
2016-07-25, 08:32
Soldiers often experience severe energy deficits during military operations that diminish whole-body protein balance, even when dietary protein is consumed within recommended levels (1.5-2.0 g·kg-1·d-1).
PURPOSE:
To determine whether increasing total protein intake above current recommendations or increasing energy intake equally mitigate protein loss during energy deficit.
METHODS:
73 Norwegian Soldiers participating in a 4-d arctic military training program (AMT, 51 kM ski march) were randomized to one of three dietary groups; control (CON; n = 18, 3 combat rations per day), protein (PRO; n = 28, 3 rations plus 4, 20 g protein, 250 kcal protein-based snack bars per day), and carbohydrate (CHO; n = 27, 3 rations plus 4, 48 g carbohydrate, 250 kcal carbohydrate-based snack bars per day).
METHODS:
Energy expenditure (D218O) and energy intake were measured daily. Nitrogen balance (NBAL) and whole-body protein turnover were determined at baseline (BL) and on day 3 of AMT using 24 h urine collections and [15N]-glycine.
RESULTS:
Protein and carbohydrate intake were highest (P < 0.05) for PRO (mean ± SE, 2.0 ± 0.1 g·kg-1·d-1) and CHO (5.8 ± 0.3 g·kg-1·d-1) but only CHO (3131 ± 122 kcal·d-1) statistically increased (P < 0.05) energy intake above CON (2506 ± 99kcal·d-1). Energy expenditure (6155 ± 60 kcal·d-1) and energy deficit (3313 ± 93 kcal·d-1) were similar across groups. Whole-body net protein balance (-0.24 ± 0.11 g·d-1) and NBAL (-77.1 ± 10.9 mg·kg-1·d-1) were negative at the conclusion of AMT in all groups. In a combined cohort, consuming more energy was associated with higher (P < 0.05) net protein balance (r = 0.57) and NBAL (r = 0.60), independent of macronutrient intake. Soldiers consuming the most energy (3754 ± 94 kcal·d-1) also consumed more (P < 0.05) protein (2.1 ± 0.1 g·kg-1·d-1) and carbohydrate (6.6 ± 0.3 g·kg-1·d-1) than those who consumed the least amount of energy (1783 ± 113 kcal·d-1, 1.2 ± 0.1 g protein·kg-1·d-1 and 3.3 ± 0.3 g carbohydrate·kg-1·d-1), and achieved net protein balance and NBAL during AMT.
CONCLUSION:
These data reinforce the importance of consuming sufficient energy during periods of high energy expenditure to mitigate the negative consequences of the energy deficit and attenuate whole-body protein loss.
Energy Not Protein Or Carbohydrate Intake Attenuates Whole-body Protein Loss During 4-d Arctic Military Training. Medicine & Science in Sports & Exercise: May 2016 - Volume 48 - Issue 5S - p 444.
PURPOSE:
To determine whether increasing total protein intake above current recommendations or increasing energy intake equally mitigate protein loss during energy deficit.
METHODS:
73 Norwegian Soldiers participating in a 4-d arctic military training program (AMT, 51 kM ski march) were randomized to one of three dietary groups; control (CON; n = 18, 3 combat rations per day), protein (PRO; n = 28, 3 rations plus 4, 20 g protein, 250 kcal protein-based snack bars per day), and carbohydrate (CHO; n = 27, 3 rations plus 4, 48 g carbohydrate, 250 kcal carbohydrate-based snack bars per day).
METHODS:
Energy expenditure (D218O) and energy intake were measured daily. Nitrogen balance (NBAL) and whole-body protein turnover were determined at baseline (BL) and on day 3 of AMT using 24 h urine collections and [15N]-glycine.
RESULTS:
Protein and carbohydrate intake were highest (P < 0.05) for PRO (mean ± SE, 2.0 ± 0.1 g·kg-1·d-1) and CHO (5.8 ± 0.3 g·kg-1·d-1) but only CHO (3131 ± 122 kcal·d-1) statistically increased (P < 0.05) energy intake above CON (2506 ± 99kcal·d-1). Energy expenditure (6155 ± 60 kcal·d-1) and energy deficit (3313 ± 93 kcal·d-1) were similar across groups. Whole-body net protein balance (-0.24 ± 0.11 g·d-1) and NBAL (-77.1 ± 10.9 mg·kg-1·d-1) were negative at the conclusion of AMT in all groups. In a combined cohort, consuming more energy was associated with higher (P < 0.05) net protein balance (r = 0.57) and NBAL (r = 0.60), independent of macronutrient intake. Soldiers consuming the most energy (3754 ± 94 kcal·d-1) also consumed more (P < 0.05) protein (2.1 ± 0.1 g·kg-1·d-1) and carbohydrate (6.6 ± 0.3 g·kg-1·d-1) than those who consumed the least amount of energy (1783 ± 113 kcal·d-1, 1.2 ± 0.1 g protein·kg-1·d-1 and 3.3 ± 0.3 g carbohydrate·kg-1·d-1), and achieved net protein balance and NBAL during AMT.
CONCLUSION:
These data reinforce the importance of consuming sufficient energy during periods of high energy expenditure to mitigate the negative consequences of the energy deficit and attenuate whole-body protein loss.
Energy Not Protein Or Carbohydrate Intake Attenuates Whole-body Protein Loss During 4-d Arctic Military Training. Medicine & Science in Sports & Exercise: May 2016 - Volume 48 - Issue 5S - p 444.