Nutrition, Hydration, Electrolytes

T1-∞
After PT, and two-three times daily thereafter

Reference: FM 21-18 Foot Marches 2017 , Appendix D, pp.D-1 through D-3

Exercise, and general performance require and assume that you're well-fed, properly hydrated, and getting the electrolytes that allow your body to build, train, and do the necessary work.

Crack open the electronic or hard-copy version of FM 21-18 Foot Marches.
Mind you, the entire manual is gold for its intended purpose, but everything, including any training and PT, depends on you, and everyone else undertaking it, to be properly fed and well-hydrated, on everything - including you - is going to fall on its @$$.

So turn to Appendix D therein, and read and absorb only the concise three pages found there:
(Sorry it grays out when I cut and paste from the pdf. Pull up your original, because I'm not going to retype the entire three pages for you.)

Appendix D

 

Restoring adequate glycogen in the muscles and enhancing muscle recovery through

proper nutrition allows the body to refuel and recuperate. This ensures positive

adaptations to stress, enhances Soldier resiliency, and optimizes gains in strength,

endurance, and mobility while controlling injuries.

  

BASICS OF NUTRITION FOR PERFORMANCE

   

D-1. Soldiers must understand what to eat on a daily basis and what to eat and drink around each and every

tactical event. The macronutrients (proteins, carbohydrates, and fats) are important to building a nutritional

foundation to conduct foot marches. Figure D-1 illustrates the general guidelines for Soldiers about

macronutrient intake and the role of these macronutrients.

  

Figure D-1. Types and percentages of fuel the body needs

   

D-2. Problems with an unbalanced diet include—

  

 Increased inflammation.

 Compromised immune system.

 Degraded recall and learning.

 Reduced ability to focus.

 Reduced speed and agility.

 Degraded body composition. 

 Increased fatigue.

 Increased muscle breakdown.

 Increased risk of infections and muscle strain.

 Reduced blood flow to tissues

NUTRIENT TIMING

   

D-3. Calories from carbohydrate, protein, and fat digest, absorb and metabolize at different rates in our

body. This is important to understand to take advantage of nutrient timing around intense physical activities

and to maximize Soldier performance and recovery. Nutrient timing is essential for Soldiers that have little

recover time between operations or during long distant foot marches. Since foot marching is a high energy

expenditure event, fueling before, during, and after is a critical factor in foot march performance.

  

Note. Soldiers should use extreme caution when starting fad diets or taking over-the-counter herbal

supplements. Medical records have revealed deaths and severe injuries occurring in Soldiers using

dietary or herbal supplements without medical supervision.

  

BEFORE THEMARCH

D-4. Muscles require energy to perform work and use carbohydrate as the primary fuel for intense muscular

activity. Soldiers should consume at least 1gram of carbohydrates 1 to 2 hours before foot marching. This is

to not allow the body to use muscle protein for energy during long foot marches. Having adequate

carbohydrates preserve skeletal muscle protein from being used as fuel. Choose foods low in fat and fiber to

prevent digestive upset. Examples of fast absorbing carbohydrates for this time are: energy bars, jam or jelly

on bread, granola bars, bananas, and so forth. Consuming protein 1 to 2 hours before foot marching enhances

carbohydrate absorption and helps prevent muscle breakdown during and after foot marching. Start with 0.3

grams of high-quality protein, for example, lean beef, chicken, turkey, fish, egg whites, and so forth.

  

DURING THEMARCH

D-5. Soldiers should consume small amounts of fast-absorbing carbohydrates and protein during foot

marching to prevent performance decline, excessive muscle breakdown and enhance recovery time following

foot marching. The optimal range for carbohydrate intake during foot marches is about 25 to 75 grams per

hour, divided into 4 equal parts over an hour. For example, consume the crackers or bread and the beef jerky

items from a meal, ready to eat or first strike ration at rest points and/or halts during the foot march.

  

AFTER THEMARCH

D-6. The hour immediately following the march is a crucial window of time for nutrient timing and is

important for success in follow-on operations. This is an important time to replenish glycogen (carbohydrate)

stores in muscles and the liver to prevent the breakdown of muscle and optimize recovery. Consuming

carbohydrates and protein in this window decreases muscle protein breakdown and enhances net protein

balance, essentially optimizing recovery. In addition, post activity immune function depression is most

pronounced when activity is continuous, prolonged (>90 mins [minutes]), and/or moderate to high intensity.

Consuming carbohydrates during the time immediately following the march has a positive effect on the

immune system. The optimal way to quick start the recovery process is by consuming fast-absorbing

carbohydrates and protein and limited amounts of fat within this 1 hour window immediately following the

foot march. Guidelines for macronutrient intake are given in table D-1.

 
 
 

Table D-1. Carbohydrate and protein (macronutrient) intake by body type

  

Body Weight(pounds)                     Carbohydrates  (grams)          Protein (grams)

    

120                                                      54                                 16

140                                                      63                                 19

160                                                       72                                 22

180                                                       81                                 25

200                                                       90                                 27

220                                                     100                                 30

240                                                      110                                 33

HYDRATION AND ELECTROLYTES

   

D-7. Ensuring adequate, but not excessive, hydration and maintaining an appropriate electrolyte balance

can further optimize performance. Performance deficits can begin with as little as 2 to 3 percent loss of body

weight due to sweat. On hot, humid days, Soldiers might sweat 1 to 2 liters per hour with some Soldiers

sweating as much as 2 to 3 liters per hour. Additionally, sodium lost through sweat can range from 575 to

1,725 milligrams per liter. Including sodium sources aids in reducing electrolyte imbalances and prevents

hyponatremia. Figure D-2 shows general guidelines for hydration and maintaining an appropriate electrolyte

balance.

 

 

Drink 16 ounces of water 2 hours before the march.

 

 

Drink 8 to 16 ounces of water 1/4 hour before the march.

Drink 6 to 12 ounces of water every 15 to 20 minutes during the march.

Monitor urine during the march, should be pale yellow.

Water does not replace lost electrolytes. When available, consume beverages containing electrolytes

 

(sodium, potassium, chloride) to replace losses during the march. This is especially important in

environments which increase sweat rate such as extreme heat and humidity.

 

 

Do not restrict salt in the diet.

Sodium intake of 1 gram per hour is recommended during prolonged marches where heavy sweat loss is expected.

 

 

In extreme dry heat, water and sodium needs can be as high as 10 liters and 20 grams, respectively.



Figure D-2. Guidelines for maintaining hydration and electrolyte levels


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(And if you're trying to do this on a smartphone or tiny tablet, once again, go pull up the original. That's why I gave it to you.)
That's it.

Nutrition and hydration magic (along with a spiffy diagram on the first page that doesn't clip and paste here - Read the original, that's why I gave it to you.) for not just foot marches, but every frickin' day you're sucking air and pooping, from now until you die.

You can follow those nutrition and hydration guidelines, and know how much is enough.
You can use those nutrition guidelines they now stamp on everything down to airline peanut packages, and plan what you eat.

You have, in blistering detail, the exact amount of water you should do before, during, and after exercise (which, as we covered earlier today, should be every day for you.)

Uncle Sam has broken it down, after exacting research, for average persons from 18-39.
(If you're older, have special considerations, etc., do your own due diligence.) 

I can tell you what to do.
I can share how to do it.

I cannot make you do it.
But I can give you some motivation:

Classes start after your post-PT morning meal, every day.