How to Estimate Your Food Intake and Caloric Needs for Military Training

(U.S. Air National Guard/Master Sgt. Arthur M. Wright)

Food and water are fuels in every facet of life. From providing energy to handle the daily grind to giving us nutrients we need to recover and grow stronger, what and how much we eat matters throughout our lives. The importance can be seen during long training hours when you can no longer keep up with your workouts due to low blood sugar or become a heat casualty. 

The quickest way to end your training day is to show up dehydrated and under-fueled. Fueling and hydrating before, during and after long training days will keep you in the game, but how much do we need?

If you aim to serve in challenging military training programs, preparing for the rigors of military physical testing and training requires optimal nutrition, hydration and recovery. What you eat and drink is the most critical, yet often overlooked, aspect of building your ability to handle long days and nights of physical and mental stress. Understanding and estimating your daily caloric needs primarily depends on your age, gender and activity levels. Proper caloric intake not only fuels your workouts but also aids in recovery, ensuring that your training is effective and sustainable.

When gearing up for military training, you're not just any athlete. Your regimen will likely push you to the edge: cardio drills, strength training, long marches with heavy loads and obstacle courses that test every muscle and sinew. Consequently, your caloric needs are substantially higher than for the average person. Here is how you can determine how much food and water you need each day to sustain high levels of activity:

Basal Metabolic Rate and Total Daily Energy Expenditure

Basal metabolic rate (BMR) is the number of calories your body needs to maintain basic physiological functions at rest. BMR will give you a good start and ballpark average of how many calories you burn each day by just living. Various calculators are available online to help you estimate this based on age, gender, weight and height -- like the ones at I prefer this one as it also conveniently shows you the activity level you might add to your day and adjusts the total calories needed for each day. 

For example, if you're a 25-year-old male weighing 180 pounds and standing six feet tall, your BMR might hover around 1,839 calories daily. However, if you exercise daily or have a physical job, the calories required to maintain weight and performance will be up to 3,173 calories daily.

If you want to calculate your total daily energy expenditure (TDEE) based on your BMR, here's how you can do it. Factor in your activity level, which can be categorized as sedentary (x 1.2), moderately active (x 1.55) or very active (x 1.725). Given that you are preparing for something as strenuous as military training, you will likely fall into the "very active" category. Multiplying your BMR by an activity factor -- typically around 1.725 for very active individuals -- will give you an estimate for your TDEE. 

Using our earlier example, this comes to about 3,105 calories per day. As you can see, the online calculators and the common BMR/TDEE factors give similar estimates for a person's total calories needed to perform at their best (and maintain a healthy body weight).

If you wanted to lose weight, you would reduce those total calories by 500 daily for a pound of weight loss each week. You could add 500 calories to those scores to gain one pound of mass each week. So you must consider the amount of activity you add to your day to determine how much you need to eat to gain or lose weight.

As stated, these are ballpark calculations, and real-world scenarios could deviate from these numbers. Your actual caloric needs can fluctuate based on the intensity and duration of your training sessions. Keeping a weekly food journal, tracking your food, water and caloric intake, and noting your energy levels, sleep quality and overall performance is advisable. I use a food scale from Greater Goods that creates a food label for the food you weigh. 

If you find yourself consistently fatigued or struggling to complete workouts, it might be a sign that you need to increase your caloric intake. If you do not do this, you are simply guessing, and when your future professional opportunities are on the line, you cannot afford to skip the assessment and guess.

The quality of calories is as important as the quantity. Good food choices are always the best option. Aim for a balanced diet rich in lean proteins, whole grains, fruits and vegetables. Avoid ultra-processed foods as you need good fuel for high-intensity workouts, and endurance training will deplete your glycogen stores, warranting a higher carbohydrate quantity and quality intake. At the same time, adding solid proteins aids muscle recovery and growth, which is essential for the strength and endurance required in military operations. Good fats will also be a solid caloric and energy boost, especially when the days turn to night and the energy needs for thermal regulation (body temperature) increase.

Hydration cannot be overstated. Even slightly dehydrated people can impair their physical performance and cognitive function, both of which are crucial in training and in the field. Drink ample fluids throughout the day, not just during your workouts. When sweating profusely, add electrolytes as cramping and the potential for heat-related illnesses will quickly follow every hour in the heat without water and salts. The quickest way to end your military training is not to hydrate/replenish with electrolytes properly. You could also die if the heat casualty becomes heatstroke.

(U.S. Air Force/Joshua J. Seybert)

Long, hard training days burn many calories daily, especially if exposed to cold air and water constantly. Adding calorie-dense foods at the end of the day or during snack breaks is key to sustaining performance. Food such as peanut butter, nuts, avocados and protein bars will help, while supplements like protein shakes can be useful but shouldn't replace whole foods. However, in most military training programs, supplements are not allowed. Consider supplements as tools in your nutritional arsenal, not the foundation during your preparation training time. Real food should be the go-to option, especially during military selection training.

Finally, consult a nutritionist familiar with athletic and military needs to tailor a plan specific to your body and training goals. While online calculators and generic advice are helpful starting points, a professional can offer insights tailored to your unique physiology and regimen. The key is avoiding missing out on vital nutrients by making food choices. A nutritionist can help you avoid that costly mistake.

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