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- health & safety
- clinical physiology
- education & training (see medical education & training)
- quality in health care
The human body needs adequate energy availability (EA) to maintain proper physiological functioning. EA is defined as the difference between energy intake (EI) and exercise energy expenditure (EEE) relative to fat-free mass (FFM).1 Prior work in active women suggests an optimal EA range of 40–45 kcal/kg FFM/day and a low EA (LEA) below 30 kcal/kg FFM/day, although there is individual variability.2 It is widely acknowledged that LEA is the main factor triggering the unfavourable health and performance consequences associated with REDs, including disruption of the reproductive, gastrointestinal, haematological, cardiovascular and immunological systems, as well as impairment of growth and development, several endocrine axes, bone health, mental wellbeing and various aspects of performance.1
In the military, during field training and duty, averaged estimated energy requirement is around 4000 kcal/day and it can be greater than 7000 kcal/day.3 4 Therefore, daily energy deficits are common (up to 50–70% of total energy requirements) and are caused by the high EEE of training and combat.5 Limited EI (macronutrient and micronutrient under-consumption) results from a combination of inaccessibility/unavailability of appropriate food (food insecurity), suboptimal operational rations, impaired nutrient absorption and homeostasis induced by consequent inflammatory response and loss of appetite caused by stress.5 6 There may also be frank eating disorder/disordered eating behaviours in military personnel. The state of prolonged LEA in military populations is associated with reduced LH, FSH, …
Footnotes
Correction notice This article has been corrected since it was published online. In the contributors section MLM has been corrected to NC.
Contributors NC and KEA conceived the presented idea. KEA encouraged EA to revise the data. EA wrote the manuscript. All authors provided critical feedback and contributed to the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; internally peer reviewed.