Effects of 30 Days of Undernutrition on Reaction Time, Moods, and Symptoms11The views, opinions, and/or findings contained in this report are those of the authors and should not be construed as an official Department of the Army position, policy, or decision, unless so designated by other official documentation.

Energy Deficiency in Soldiers: The Risk of the Athlete Triad and Relative Energy Deficiency in Sport Syndromes in the Military

“…Additional carbohydrate improved vigor and decreased confusion during a day of military activities, but other mood constructs were not affected and overall energy status was not measured (188). Supplementary energy during field exercises in an energy deficit had limited impact on mood disturbance (182,189,190), but the provision of fresh feeding rather than ration packs, which also resulted in increased energy intake, attenuated feelings of fatigue during a 12 day field exercise in energy deficit (35). Although controlled laboratory trials provide some support for a role of energy deficiency in mood disturbances (191,192), psychological stress is a fundamental component of military training, and combined with sleep deprivation and the potential for dehydration, mood disturbances cannot be attributed solely to energy deficit.…”

“…Shooting performance decreased during a 21 day field exercise, and although energy balance was not measured, decreased IGF-1 suggests an energy deficit (194). Shorter periods (4 days) of field training in severe energy deficit (∼2,900 kcal•d −1 ) had no effect on shooting performance (175) and high energy intakes did not improve shooting performance (208) or protect against decrements in other constructs of cognitive performance (182,209) during field exercises in energy deficit. The multi-stressors of military training, including sleep deprivation and dehydration, may contribute to impaired cognitive performance, with sleep deprivation and energy restriction likely to have independent effects (210).…”

“…Numerous studies have reported mood disturbances, as measured by the Profile of Mood States, in response to specialist military training of several days to 8 weeks in energy deficit (35,147,173,(175)(176)(177)(178)(179)(180)(181)(182)(183). The 8 week US Army Ranger course increased tension, depression, anger, fatigue, and confusion, and decreased vigor (176); similar disturbances to mood have been reported following just 3 days of sustained military activities in severe energy deficit (∼3,000 kcal•d −1 ) (175,178).…”

Physiological Factors Which Influence Cognitive Performance in Military Personnel

“…Undernutrition resulting from the consumption of lightweight rations appeared to impair performance on tasks of processing speed, but only when the period of ration consumption was extended (e.g., 30 days). Simple reaction time was ~3% slower in special forces who consumed lightweight rations (1,946 kcal) for 30 days compared with those who consumed fully nourished rations (2,782 kcal; Lieberman, Askew, Hoyt, Shukitt-Hale, & Sharp, 1997; Shukitt-Hale, Askew, & Lieberman, 1997). The number of omission errors on a choice reaction time task was also more than doubled (Shukitt-Hale et al, 1997).…”

An augmented food strategy leads to complete energy compensation during a 15‐day military training expedition in the cold

“…Multi-day military training expeditions offer an interesting opportunity for studying energy compensation since they submit individuals to mandatory long and repeated periods of sustained physical activity, resulting in high energy expenditure (EE). Surprisingly, results are generally characterized by what some have called "voluntary underconsumption" (Shukitt-Hale, Askew, & Lieberman, 1997). This phenomenon, which is characterized by inadequate EI during high EE, occurs even when the total energy content of available foods largely exceeds energy requirements (Askew et al, 1987;Cline, Tharion, Tulley, Hotson, & Lieberman, 2000;Edwards & Roberts, 1991;Edwards, Roberts, Mutter, & Moore, 1990;Hoyt et al, 1991Hoyt et al, , 1994Jones, Jacobs, Morris, & Ducharme, 1993;King et al, 1992;Lester et al, 1993;Lichton, Miyamura, & Mcnutt, 1988;Morgan et al, 1988;Popper et al, 1987;Roberts, Mcguire, Engell, Salter, & Rose, 1989;Schoeller, Field, & Delany, 1988;Shukitt-Hale et al, 1997;Thomas et al, 1995).…”