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US Military Athletes: Body Composition Through Fasting in Training

By Mark E. Jones, M.S., ACSM-EP, TSAC-F

and Daniel G. Graetzer, Ph.D.
Faculty Member, School of Health Sciences

The U.S. military has long been assessing servicemembers within all its branches using two general standards: body composition and tactical performance capabilities.

While body composition and physical abilities are often considered to be independent factors in some realms, they do relate to each other in the sense that activity/lifestyle habits play a major role in “forming” an individual.

US Military Fitness Specifications

In the World War I era, the U.S. Army had strict fitness standards that involved height-to-weight tables with three criteria for original entry, although some specific duties carried guidelines that were a bit stricter. According to the Army, WWI recruits had to be a minimum of 64” tall with their chest measuring at least half of their height and have a body weight between 128 to 190 pounds

There are still guiding principles for height and weight. However, military standards have since become a bit more diluted compared to original criteria, notes

Obesity Upon Entry to Military Service and Thereafter

Maintaining an appropriate body composition is critical for military readiness with soldiers given continually updated guidelines laid out by Army Regulation 600-9 (The Army Weight Control Program) for height to weight ratios and ultimately body composition. According to 2021 statistics from the Centers for Disease Control and Prevention, servicemembers had an obesity rate of 19%, up from 16% in 2015.

The Pentagon reported that 77% of young Americans were not eligible for military service without a waiver with one of the top three causes being obesity (the other two were drug use and having mental/physical health issues), according to A potentially dangerous precedent evolved in that drastic measures such as extreme fasting were needed to achieve weight loss at a rapid pace for those seeking to quickly qualify to enlist in military service. 

Fasting and Exercise

While many tactical athletes resort to increased physical training intensity and frequency, one current trend in many military communities involves different forms of dieting. One such diet generally known as Intermittent Fasting (IF) can be broken down into three categories: Whole Day Fasting (WDF), Alternate Day Fasting (ADF) and Time-Restricted Feeding (TRF), according to Healthline.

TRF has become extremely popular at many military bases and is rapidly trending worldwide, notes Nature.

Physical Readiness Training and the Army Body Composition Program

Soldiers perform physical readiness training (PRT) an average of five days per week with some Military Occupational Specialties (MOS) conducting PRT as little as three days weekly. Individual training plans are prescribed on a case-by-case basis.

Time frames for PRT begin as early as 0500 hours and are typically one hour in length. PRT sessions are crucial to mission success, so they must be adhered to regardless of the long work hours already required of many servicemembers.

When service hours need to be extended on a daily basis and prolonged for several weeks to months, soldiers are at higher risk for injury with intrinsic factors such as body mass index and physical fitness used to identify risk. Tactical athletes are thus experimenting with alternative ways to prevent potentially being placed on the Army Body Composition Program (ABCP).

The ABCP is outlined in Army Regulation 600-9 and is designed to enhance readiness for units by assisting soldiers who are at risk of not meeting fitness standards. The fear of potentially being discharged if they fall outside of regulatory guidance is a major influence on many soldiers who are contemplating intermittent fasting.

Related link: Healthy Diets: Comparing Paleo, Keto and Mediterranean

Effects of Fasting

Many physiological factors play a role in the degree of individual readiness of modern-day tactical athletes. To be effective in combat and their daily duties, soldiers must be able to adhere to the numerous physiological demands placed on them to maintain body composition and fitness standards.

The idea of regular fasting was popularized by Bill Phillips in his book series “Body for Life,” initially printed in the late 1990s. Phillips promoted that a 20-minute workout at high intensity in a fasted state could potentially burn fat faster and more efficiently than one hour of cardio postprandial (after eating).

An increasingly popular IF method is TRF – something which servicemembers typically use inadvertently as PRT sometimes is forced to run late. This delay can leave soldiers without meals until after mid-morning. 

Related link: Racewalking Can Be a Great Way to Stay in Shape or Compete

Fasting, Feeding and Training for Military Athletes

In the 2022 International Society of Sports Nutrition Position Stand: Tactical Athlete Nutrition, a fasting/feeding ratio of 16:8 was associated with reductions in body fat percentage and maintenance of performance indicators such as a vertical jump and one repetition back squat and bench press. However, when the main goals are to build functional muscle to improve tactical performance, PRT in an unfasted state is more beneficial for most individuals than working out in a fasted state.

military athletes 2 Graetzer Jones
When the main goals are to build functional muscle to improve tactical performance, physical readiness training in an unfasted state is more beneficial for most individuals than working out in a fasted state.

The overall current consensus is that physical training in a fasted state (if done safely) often helps reduce body fat percentage and overall body weight on a scale, says Medical News Today. Probably the best route to reduce body fat and achieve specific performance goals that also contain an important concentration component is to consume a smaller-than-usual amount of food prior to PRT.

Maintaining an appropriate body composition certainly increases the mission readiness of individuals and teams in all branches of the military. Maintaining a steady approach to incorporating IF is optimal with risk of injury or illness increasing over the long run if extreme fasting is attempted.

Ensuring that servicemembers remain ready to act at any given time starts with readiness and staying within regulatory guidance. Taking care of oneself while not hindering tactical athletes serving on the same mission is critical.

Throughout the military, fat weight may increase with aging, even though overall body weight may remain the same. For instance, a soldier may weigh 150 pounds at age 20 and still weigh 150 pounds at age 60 but that soldier’s percentage of body fat may have more than doubled.

This “creeping obesity” can make a tactical athlete “overfat” even though they do not outwardly appear to be overweight. Comprehensive physical training plans with detailed outcomes designed to protect the protectors by improving body composition and tactical performance will be outlined in future Edge articles.

About the Authors

Mark Jones

Mark E. Jones, M.S., ACSM-EP, TSAC-F, earned both his bachelor of science and master of science in sports and health sciences from American Public University. Though his master’s, he maintained a 4.0 GPA and graduated with distinction. His capstone project, “Tactical Athletes Body Composition & Performance Effects while Training in a Fasted State” is available online and was written under the guidance of Dr. Daniel Graetzer. Mark is in his final didactic year of his Ph.D. in exercise science at Concordia University of Chicago, where he is focusing on applied nutrition and men’s hormone health.

Mark is the Supervisory Health Educator for the Fort Bragg Army Wellness Center and an adjunct instructor at Maryville University of Saint Louis. Mark serves in two volunteer roles. He is on the University’s Industry Advisory Council for Sports and Health Sciences and also serves as a member of the American College of Sports Medicine Committee on Certification and Registry Boards for Exercise Physiologists.

Daniel Graetzer color

Daniel G. Graetzer, Ph.D., received his B.S. from Colorado State University/Fort Collins, a M.A. from the University of North Carolina/Chapel Hill and a Ph.D. from the University of Utah/Salt Lake City. He has been a faculty member in the School of Health Sciences, Department of Sports and Health Sciences, since 2015. As a regular columnist in social media blogs, encyclopedias, and popular magazines, Dr. Graetzer greatly enjoys helping bridge communication gaps between recent breakthroughs in practical application of developing scientific theories and societal well-being.

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