Fitness requirements for the military are changing. This also means a change in diet and nutrition.
This article discusses the need for adequate calories, but mainly adequate nutrition to enable a state of readiness.
Here we shall look at the following key points:
- Soldier Fitness
- Importance of good nutrition
- Soldier Athlete
- Soldier Nutrition
- Military Personnel Micronutrient Recommendations
Let's firstly take a look at why military fitness is evolving.
The military has recently moved away from tests focussing on endurance and aerobic fitness to now including explosive strength, power, and anaerobic capacity.
The old tests used to simply include a timed run, plus the number of sit-ups and press-ups that could be achieved within a time frame.
Military Strength and Conditioning Program
It has been argued in the past that the former PT tests do not predict military task performance due to sit-ups and press-ups being very different from the load carrying and lifting that soldiers tend to do in their roles. 
However, now, to reflect the demands of recent conflicts there is a much more varied number of tests that soldiers need to complete.
Furthermore, consideration is now placed on avoidance of Muscular Skeletal Injury. 
The British Army for example now includes the following six standards as of 2019:
- Loaded march/ruck with 40kg (88lbs) and another with 25kg (55lbs)
- Tactical bounds, sprints, crawls
- Casualty drag comprising of 110kg (242lbs)
- Water can carry: 2 x 25kg (55lbs)
- Lift and pause of 70kg (154lbs)
- Shoulder bag carry
Clearly, we can see that these tests include lots of core strength capability which is a dynamic shift from merely running, tabbing, or rucking long distances.
Since 2001, the USA, UK, and allies have been embroiled in the War on Terror which has seen millions of troops deployed and thousands killed or injured. 
Furthermore, while the War in Iraq which commenced in March 2003 could be considered as a conventional offensive, it was the following counter-insurgency campaign and the War in Afghanistan that saw a key change in warfare.
It was commented that identifying and thus fighting the insurgents was very difficult.
The (insurgents) could be a normal local one-minute mixing with civilians, then in the next minute be directing IED fire towards allied conventional forces using sporadic but organized hit and run tactics. 
This brought upon a change in allied tactics and the development of equipment.
The result was more body armor, more weight to carry and slow, arduous foot patrols or combat vehicle dismounts as the allies become drawn into asymmetrical warfare. 
Along with fighting guerrilla-style insurgents saw the average troop on the ground carrying 50kg (110lbs) of kit, which naturally slowed them down and made it more difficult to fight against a person wearing little but local clothes and carrying a rifle. 
This change of individual equipment and vehicles that were initially fast and maneuverable became much heavier and protected. 
It can be suggested that this change is a reflection of the new fitness tests and how they reflect the real-life scenarios and tasks that operating soldiers face. 
Something echoed by the 2015 National Defense Authorization Act which requires that occupational standards "accurately predict the performance of actual, regular and recurring duties of military occupation." 
A statement further qualified by Aaron Ferencik, US Marine veteran. 
As we can see, training and soldier fitness requirements have been under scrutiny to reflect the changing faces and demands of war.
We are now seeing much more in the research of strength development and conditioning that is working its way down to the soldier training.
Especially as it was discovered that overuse injuries were the most reported injury type from collected data over a two year study period of infantry soldiers. 
The high rate of injury among military personnel can be attributed to high running mileage and high amounts of weekly physical training which can hinder military readiness while increasing costs. 
Importance of Good Nutrition
Even as far back as Victorian-era Britain, the result of varying degrees of nutrition was visible amongst soldiers spanning the British Isles. 
It was observed that those officers from wealthier backgrounds were taller than other male recruits from poorer regions.
There was also a trend off those being from rural northern areas and Ireland being of a taller height while being more robust compared to those from the heavily populated and industrialized areas around London suggesting nutritional disparity.
It was noted that those poorer families who lived in urban areas had limited resources. This meant their diets mainly consisted of white bread with potato, and when it could be afforded, it may have been supplemented by vegetables and expensive meats.
However, there was very little milk available while tea would have been the main beverage.
These families lived on a wage economy, whereby they were paid money for their labor and toil. This meant they their choices in foods were limited.
In contrast, those of a poorer background who lived in isolated rural areas would have been paid with a plot of land to grow crops, vegetables, and even rear livestock.
This meant that their nutrition was much more varied and complete. This was much more evident in the Scottish Highlands who had plenty of access to milk and oatmeal. 
This information correlates with survey data from this time period which also demonstrated that the best-fed regions were further away from urban areas who suffered slum conditions, disease, pollution, and little sunlight.
This resulted in lower mortality rates for the rural populations as these people had diets that were nearer a Mediterranean dietary standard.
Diet and Nutrition
During the first half of the 1900s and late 1800s, the poor of the United Kingdom suffered from malnutrition, disease, infection, and deficiencies that are seen in the poorest of Africa and Asia of today.
While this plight was going on for years, it wasn't until the British lost wars in South Africa towards the turn of the 20th Century which stimulated the UK government to take heed of the nutritional crisis among the working classes which often produced the fighting men. 
It was further observed that the growth of a person wasn't necessarily down to genetics, but it was found that meat, whole milk, butter, and sugar helped children to put on weight and boost the height of children.  
This was exemplified by the size, stature, and physical robustness of Scottish soldiers (who were the backbone of the British Army and its Empire) pre and post Industrialism.
Prior to industrialism, many people of Scotland were paid in kind by a share of crops, livestock, and the produce from the land. This provided a varied and nutritious diet.
This resulted in strong men who were on average 6 feet tall, with many being taller.
Yet, once industrialization was in full force, bringing with it a country that became the world's biggest industrial powerhouse, so did the introduction of wages as people migrated to urban areas.
As a result, they no longer had access to a nutritious diet from living off the land but did have access to cheap imported and more convenient foods.
It wasn't that people were starving, but more a combination of cheap food that wasn't nutritious; the introduction of high-fat canned meats, high sugar content canned fruits and dark slums with choked air that prevented exposure to vitamin D. 
Now, the men were up to 6 inches shorter than their forefathers, they were weaker and couldn't fulfill the basic fitness required of the infantry.
By the time the Great War came in 1914 up to half of the recruits were rejected. Prior to this, back in 1883, the army had to reduce the minimum height of soldiers by 6 inches.
Blockade of Germany
Interestingly the Great War was lost by the Germans mainly due to the population being close to starvation. This was known as the 'Blockade of Germany'. 
With a second war looming, it stimulated the British government to reassess food, agriculture, and nutrition policy to ensure soldiers and workers were fit for fighting.
This saw a nationwide nutrition policy created by scientists and nutritionists overseen by the Ministries of Food, Health, and Agriculture. It placed as much importance of nutrition for the national population as engineers did for creating machinery. 
Nutrition and Exercise
Clearly nutrition is key to having a healthy, productive population. In some respects, those who lived in the Mid-Victorian era (1850-1870) did have this down to a tee (pun intended).
Much of their day was taken up by physical labor. They also had access to what would now be considered 'organic' and nutrient-dense foods before a change in available foods came around in the late 1800s.
Their calorie intake was almost double of what we would consider normal today, but because their physical output was so high obesity and overweight people were rare.
Those that survived childhood would go on to lead long lives. Degenerative diseases and cancers were also rare. 
The reasons behind premature death were usually brought on by infection or trauma. 
So we can see that even many years ago, with the right foods and with plenty of physical exercises, as long as you dodged infant mortality, infections such as TB and industrial accidents men could expect to live up to 75 with women reaching 78 according to some studies. 
A good diet of whole, natural foods plus lots of exercise is key and was key back then to a long life.
But what about other areas? Of course, we all want to lead long lives, but can it also improve other aspects?
Ancient Sports Science
Even since the first Century BC there has been an appreciation and recognition of the benefits exercise and diet can bring. 
And, to this date, it is widely accepted that athletes require an adequate intake of vitamins and minerals, plus proteins along with other micronutrients to avoid immune dysfunction. 
Furthermore, the World Health Organization (WHO) stipulates that regular physical activity has significant health advantages which can reduce the risk of degenerative disease, osteoporosis, obesity, diabetes while improving mental well being. 
The WHO also accept that poor nutrition contributes toward cancers, cardiovascular diseases, and noncommunicable diseases.
They conclude that most countries' populations have excessive consumption of fats with a lack of fruit and vegetables which results in obesity, reduced quality of life, and a shortened life. 
It also comes as no secret that the world, even while there is a widespread famine in some regions, is facing a public health crisis.
The obesity epidemic is growing globally, and as of yet, not a single country has been able to reverse it.
This is due to an imbalance of calories consumed and those calories expended through exercise. 
Therefore, it is advised that we eat a calorie-controlled diet coupled with exercise that will use more calories than consumed to maintain a healthy weight or to lose weight.
To reduce the risk of chronic disease, 30 minutes of exercise per day is recommended as an adult.
While exercise such as running or cycling is often touted, muscle strengthening exercises can also be incorporated as more muscle mass burns more calories throughout the day, even at rest. 
These recommendations are due to the reduction of physical activity seen across much of and the globe since the invention, rise of labor-saving devices, and change of working practices.
This has resulted in Americans becoming heavier (although not just Americans) when even the ancient Greeks and Romans appreciated the importance of exercise to maintain a healthy body. 
Members of the military tend not to fit in the contemporary model as civilians.
Soldiers generally lead more active lives, they burn more calories and have different nutritional requirements that would be similar to that of an athlete.
For instance, in 2002, it was reported that during basic combat training recruits were consuming on average 3,386 calories per day and were supporting a healthy body mass index.
This actually resulted in a loss of 2.29kg in body weight on average. 
The Navy SEALS state that Special Operations Forces require at least 3000 calories per day. 
This is comparable to a study regarding energy requirements for British Military personnel which states there is an average of 3,600 calories required for active service to fuel their training.
However, the median figures range up to 4,600 calories for infantry, guards, parachute regiment, and royal marines. 
Implications for Calorie Deficient Soldier
While the recommended daily intake of calories is 2,500 for men, it is clear that military service personnel require more, in some cases over 2,000 more.
We know this is because they lead active lifestyles. Yet, what would happen if they didn't reach the calorie requirements?
As far back as 1957, it was concluded that if a calorie-restricted intake did not breach a loss of more than 10% of body weight then there would be no loss in physical performance. 
This was based upon a typical soldier weighing 75kg (165lbs) with 15% body fat. This level of fat could fuel a soldier for up to 75 days whilst receiving an energy deficit of 1000 calories.
Thereafter, the body will start to use muscle and organ protein for energy. 
This was observed over a period of 148 days during 1915 and 1916 throughout the Siege of Kut which involved British and Indian soldiers defending a garrison against Turkish forces.
Once the butter and bacon reserves ceased, it was noted the soldiers started to lose muscle mass. Even horsemeat couldn't sustain their previous muscle levels.
Those Indians who wouldn't eat the horseflesh suffered worse.
The resulting outcome was that the British soldiers were experiencing partial starvation and the Indian's were at a severe level of chronic starvation.
The Indian's started to show reduced energy levels, were less capable than their British counterparts, and were less resistant to disease.
However, towards the end of the siege, all soldiers were extremely fatigued, finding it difficult to respond to illness and took every opportunity to rest.
This became apparent when the soldiers had to rest after just 10 minutes of trench digging, and sentry duty was halved from 2 hours to just 1. 
Calories and Nutrition
The Indian soldiers from the Seige of Kut suffered worse than the British, and this was due to the difference in rations.
The British were eating a variety of foods that consisted of carbohydrates, sugars, fats, and protein from meats.
When the supplies were running low and there were little in the way of those much-needed elements and their performance suffered.
Of the Indians that initially refused to eat horsemeat, they were more susceptible to illness and fatigue. Eventually, near the end of the siege most did start to eat the meat.
So what this tells us that we cannot just rely on 'energy' intake.
The soldiers that had carbs, fats, and proteins suffered to a lesser degree.
There is a debate regarding the similarities between soldiers and athletes, particularly at the Special Operations Forces level.
Both groups require the mental and physical stamina to endure extreme hardship to reach their goal.
However, for the soldiers, this can mean a matter of life and death or life-changing injuries.
For the athlete(s) they have a team of nutritionists, a trainer, physiotherapists, time to recover, and have to focus on one area of excel.
On the other hand, soldiers have to excel in a much wider variety of skills all year round. They rarely have time to recover both physically, or mentally and do not have the full spectrum of support around them to ensure their nutrition or training is appropriate.
With this in mind, there is also little wonder that servicemen and women go on to become Olympic athletes in their own right. This is common throughout many different military forces across the globe.  
The notion that a soldier performs a role in many respects similar to a professional athlete has been taken in to account. It has been observed that recruits of phase one training within the British Army have energy expenditures that are comparable to athletes. 
Additionally, the US Army published a study in 2018 whereby soldiers underwent a program of coaching to improve their mental agility, heart rate control, goal setting, imagery, and positive self-talk, as professional athletes would. 
The result was that there was a significantly higher improvement of APFT scores for the group. The findings are in alignment with the US Army's strategy to increase readiness and resilience. 
This strategy is in response to the Army seeing a decline in the overall fitness of recruits. The Soldier Athlete Initiative focuses on a number of areas such as physical ability which includes strength as well as aerobic and anaerobic fitness.
There's also a focus on injury prevention.
A study saw that a large percentage of recruits facing British Army basic training would suffer from musculoskeletal injuries due to a failure of the recruits to adapt to the rapid rise in distance and weight carried.
This would mean more recruits spent in rehabilitation centers, a higher cost associated with training, and an increase of manpower required. 
Furthermore, the Soldier Athlete Initiative places an emphasis on performance nutrition ensuring that the newest soldiers and recruits receive numerous nutrient-dense food options. 
Lessons are also provided to the soldiers regarding performance nutrition so they can make a conscious choice of what they eat.
According to studies, soldiers going through basic training fall below the nutritional requirements of their bodies.
This is true across both the British Army and the US Army plus other forces.
Phase One training within the British Army is 14 weeks long.
Due to the high intensity of training loads and energy expenditure, phase one training is characterized by a high rate of injury and medical discharge. 
Therefore, to minimize injury and to maximize performance, the body needs to have its nutritional and energy requirements fulfilled.
The foods you consume have an impact on your performance, quality of life, and longevity.
There are three main sources of fuel or energy for your body. These are carbohydrates, fats, and protein as the soldiers at Kut sorely required to maintain fighting fitness.
The requirement for carbohydrates is often under-appreciated.
While they are sometimes referred to as 'bad', and contributing to weight gain, a deficiency of carbohydrates can reduce mental and physical performance. 
Yet, when soldiers or anyone who is undergoing a rigorous and demanding training routine should commit 60% of their energy sources from eating carbs. 
The Human Performance Laboratory of the University of Texas recommends that carbohydrates are ingested before, during, and after intense exercise to prevent glycogen depletion and therefore minimize fatigue while providing sufficient carbs for muscle contractions on consecutive days. 
It is suggested that at least 600 grams should be eaten over a 24 hour period and that 200 grams should be eaten within the 4-hour window prior to exercise.
However, further analysis suggests that anyone who is training for 2 hours per day or more should consume 10 grams per kilogram of bodyweight. 
Furthermore, low levels of carbohydrate stimulated cortisol release which can have a negative effect on the cells of the immune system. 
Additional research has proven that carbohydrates have a direct and indirect regulation of muscle adaption to arduous training regimes. 
Fats are also another important requirement to aid the performance of a soldier and athlete.
Whereas 60% of energy should come from carbohydrates, fats should make up around 20% of their energy intake according to a study from the University of Birmingham. 
Reducing fat intake in fear of gaining fat and weight can reduce an athlete's intake of proteins, furthermore, it can also prevent the nutrient intake of fat-soluble vitamins.
The body also requires polyunsaturated fatty acids such as Omega-3 and Omega-6 which cannot be synthesized by the body. 
Trans fats should be no more than 1% of your calorie intake and saturated fats to be no more than 10%.
The rise of protein-based drinks and foods has soared in popularity due to their widespread marketing of them helping people become muscular and strong.
While the marketeers are not wrong, protein can also help provide your body with energy, although energy is not its primary role.
The main function of protein is to help with muscle contraction, muscle formation along with other tissues such as hair, skin, and nails.
For those involved in high-intensity training, it is now suggested that protein consumption is well above the recommended daily intake in the region of 1.8 grams per kilo of bodyweight. 
Anything less than this could be associated with a negative nitrogen balance, particularly those who are involved in bouts of endurance activities. 
A well-balanced diet in accordance with their energy requirements should fulfill protein needs, but people who are vegetarians are at risk. 
Vitamins and Minerals (Micronutrients)
It is estimated that 2 billion people around the world are suffering from micronutrient deficiencies as reported by the Food and Agriculture Organization of the United Nations. 
Deficiencies can cause malnutrition which can hinder the growth and development of the body. 
Athletes and those under high-stress physical activities are reported to have inadequate macro and micronutrient intakes. Yet, stresses caused by intense exercise can increase the need for additional micronutrients. 
If a person is experiencing deficiencies it can be linked to poor athletic performance.   
One thing to note is that vitamins can not be synthesized by the body, so we need to get them from food sources.
Military Personnel Micronutrient Recommendations
You may not be surprised to hear that vitamins and minerals are the most popular and often consumed dietary supplements among soldiers. 
As we know, some micronutrients are essential to life, being important for physical and cognitive function.
While there are recommendations for the general population in regards to micronutrient and macronutrient intake, some military personnel may need to maintain a higher rate to optimize performance.
The US Military Dietary Reference Intake concludes that male military personnel needs considerably more protein, vitamin A, Iron, and sodium. 
Being exposed to extreme environments also requires additional water and calorie requirements to avoid impaired thermoregulation, muscle glycogen, and fine motor co-ordination which can result in a reduced work capacity and effectiveness on the battlefield. 
As previously discussed, military and athletic performance are very similar, although there are far more variables for the soldier to contend with.  
Furthermore, a reduction in body weight from inadequate nutritional intake correlates with a reduction of strength and a reduction of maximal aerobic capacity as reported by Marriott BM, ed. 
Micronutrients of Interest
It is recommended that those serving military personnel increase certain micronutrients due to the additional stresses placed on their bodies from arduous training.
There is a proven link between an iron deficiency and a reduced work capacity through impaired muscle function, cognitive performance as well as overall health. 
Many factors can reduce iron status, these can be as follows:
- Rapid growth
- High altitudes
It is also important to understand that we would typically intake 6mg of iron per 1000 calories consumed, thus a lower energy intake can also impair iron take up. 
Once more, it is estimated that up to a quarter of the world's population is deficient in iron. 
Those who are involved in endurance activities and vegetarians need to ensure they take get enough iron from their diet and nutrition. 
The assault ration pack available in the US military states that it should contain up to 18mg daily to compensate for losses during high-intensity exercise through sweat.
Your body needs vitamin A for the immune system. Lack of vitamin A can lead to spontaneous infection. 
Vitamin A also helps to maintain healthy skin and your vision in low light conditions. 
Yet, vitamin A is also essential to the growth and survival of humans.  Even so, it is estimated that 125 million people are at risk of a deficiency. 
Studies during the Second World War saw that 2 previously healthy medical human experimentation volunteers developed tuberculosis after 16 to 20 months of vitamin A deprivation.
The military isn't immune to the effects of a vitamin A deficiency, either. During the US Civil War, many soldiers were suffering from night blindness as they were forced to live off a diet that was nutritionally deficient. 
It was concluded that vitamin A deficiency is the most synergistic with infectious diseases more than any other nutritional deficiency. 
In 2006, it was discovered that 3 Meals Ready to Eat and First Strike Rations did not provide the required zinc levels for both male and female soldiers. 
It is now considered that a ration pack should contain up to 25mg of zinc.
People who are subject to high levels of exercise can see an increased loss of zinc which can induce a zinc deficiency.
Studies have identified that highly trained individuals have lower zinc concentrations compared to people who do not train. 
This can cause health and immunity issues as zinc has been identified over recent years as being essential for the development of the immune system. 
Furthermore, this trace element can help with protein and DNA synthesis which can help soldiers (who face intense metabolic challenges) protect against diseases that could affect soldiers such as diarrhea, malaria, and respiratory health. 
Research has demonstrated that a reduction of zinc intake saw a decreased oxygen intake and a reduction of total muscular work capacity. This is why it is recommended that military personnel increase their intake by 3.3mg daily. 
Zinc is also proven in studies to improve sleep.
Sodium is an essential electrolyte and helps balance water in your cells. It is responsible for stable blood pressure as well as muscle and nerve functions. Without it, you would die. 
The US FDA recommends that the general population have a daily intake of 2.3g daily. 
However, for soldiers, intake requirements can vary due to their workloads and environments.
Particularly very hot, humid, and enduring strenuous exercise which stimulates heavy sweating.
Yet, there are concerns that those who drink too much fluid (without adequate sodium increases) can reduce the sodium concentrations in the blood, this has resulted in death.
Those living on garrison typically consume 5.5g of sodium daily. Ration packs include up to 7g, but this figure does not include the additional salt packs.
For those in very hot environments, an additional 12g should be available to supplement their diet.
This is especially true for soldiers who are rapidly deployed to places that are extremely hot yet have not had the opportunity to acclimatize. Soldiers in these scenarios have experienced heat exhaustion within 2 days of arriving. 
Vitamin D is not on the list issued by the military that requires any more intake than what a civilian would need.
However, as per the World Health Organization, much of the global population is vitamin D deficient.
Not only that, but it is also reported that there are widespread vitamin D deficiencies among active-duty soldiers. 
Research shows a strong correlation between a lack of vitamin D with impaired physical and cognitive function.
This deficiency can lead to lower testosterone levels, muscle weakness, injury, increased stress, and inflammation.
There's also evidence that suggests a link to an increased risk of posttraumatic stress disorder (PTSD).
It is advised that the supplementation of vitamin D can have a positive impact on operator health and performance. 
We have learned that the modern-day soldier has evolved. Their fitness requirements, along with their nutritional needs are more akin to an athlete.
We have seen the result of the lack of nutrition when in combat through the Seige of Kut, but also that proper nutrition itself is more valuable than just calories.
The need for a nutritious diet including a good variety of carbohydrates, proteins, fats with vitamins and minerals was evident for fighting wars, and even army recruitment.
The result of malnutrition in Britain's industrial boom saw men that shrunk by 6 inches in height over generations due to period convenience foods.
However, many military personnel are still not getting all of the nutrients they need.
This article outlined the nutritional balance required for 'soldier athletes' due to their arduous training and the continued state of readiness.
Therefore, a higher level of certain micronutrients are required to ensure their performance is enhanced and they have the ability to win the fight.
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