Body fat percentage is an important indicator of health and overall stamina. Therefore, the US Army has devised a standard to compute total body fat at the time of recruitment in military service.
The army body fat calculator is a useful online tool that uses the army’s formula to estimate your body fat percentage. In this post, we explain the various variables of the calculation, the effects of body fat on your health in relation to the maximum body fat percentage.
What Is Body Fat?
Fats are medically known as adipose tissue. Made of fatty acids, fats are one of the major components of the body and are used to fuel physiological processes and activity.
In the body, fats occur under the skin (subcutaneous fat), between the organs (visceral fat), and as part of the bone cavities (bone marrow fat).
Types Of Body Fat
The fat content of the body is divided into two types; essential body fat and storage body fat.
Essential Fat
Essential body fat is what you need to carry out your regular physiological processes like hormone regulation, fertility, insulation (temperature regulation), vitamin absorption, and storage.
It is concentrated in nerve tissues and bone marrow but also occurs as visceral fat and typically forms 3% of the total weight in men and 12% in women.
Natural lipid metabolism enables our body to synthesize some of the fats. Unfortunately, essential body fat can not be produced naturally and, therefore, needs to be consumed in the diet.
Sunflower oil, sesame seeds, pumpkin seeds, walnuts, soy milk, fatty fish, etc., are common sources of essential body fat.
Storage Body Fat
Fats are used as an energy reserve at times of calorie deficit. Therefore, the fat you consume in your diet, as well as the one produced in the body (from excess proteins and carbohydrates), is reserved as storage body fat.
This type of body fat primarily occurs as subcutaneous adipose tissue.
Types Of Dietary Fats
The fat present in food is classified into two types; saturated and unsaturated:
Saturated Fats
Saturated fats are considered harmful as they raise low-density lipoproteins (LDL cholesterol) levels. LDL increases the risk of cardiovascular disease, diabetes, and metabolic syndrome.
Additionally, LDL also increases body fat deposition, which poses a risk of obesity, and related disorders.
Due to this, daily saturated fat intake should be limited to 30 g for men and 20 gm for women.
Unsaturated Fats
Unsaturated fats are healthy fats that increase high-density lipoproteins (HDL cholesterol) in the blood. HDL is good for improving inflammation and stabilization of heart rhythms. It is found in avocados, nuts, pumpkin seeds, and natural oils.
In the daily diet, unsaturated fats should constitute 50 to 65% of your total fat intake.
Factors Affecting Body Fat Percentage
Here are the factors affecting army body fat percentage:
Age
Body composition, fat distribution, metabolic rate, and energy requirement – all of these factors influence army body fat percentage. Variations in all these metrics have been observed for each age group.
Metabolic rate, i.e., the speed at which your body breaks down nutrients, starts declining after 20. The reduction occurs by almost 2 to 3% every ten years, and as a result, fat naturally increases.
The reduced levels of physical activity, coupled with the natural loss of muscle mass, also increase body fat percentage. This is why seniors and older adults are at a high risk of obesity.
Gender
Due to different body compositions based on gender, separate body fat percentage formulas have been devised for men and women.
Men have more lean muscle mass as compared to women. Additionally, their metabolic rate for macronutrients (proteins, carbohydrates, fats) is also faster, which results in a low army body fat percentage.
On the other hand, women tend to accumulate more body fat due to a slower metabolic rate.
Additionally, body fat distribution also varies for both genders. Women tend to have higher fat content in the hips and thighs, whereas men collect fat in the middle abdominal region.
Since the area of fat deposition is crucial to determine the risk of metabolic disorders and health complications, separate body fat equations are needed to gauge fitness in men and women.
Current Weight and Body Height
In healthy subjects, body fat percentage is directly related to the body surface, height, weight, waist and neck circumference, etc.
Physical Activity
Metabolism and lean muscle mass are important determinants of army body fat percentage, and both these factors are directly related to physical activity.
A person who lives an active life, exercises daily, or engages in physical work, will have higher total daily energy expenditure (TDEE) than someone who lives a comparatively sedentary lifestyle.
High TDEE implies a higher metabolic rate, as the body breaks down fats and other energy sources to generate calories. This understandably reduces body fat percentage.
In nutrition sciences, physical activity is divided into six levels:
- Sedentary: Little to no exercise
- Light: Exercise 1 to 3 times a week
- Moderate: Exercise 4 to 5 times a week
- Active: Daily exercise or intense exercise 3 to 4 times a week
- Very Intense: Daily intense exercise
- Extra Active: Very intense exercise daily or a physical job
In the above classification:
- Exercise – 15 to 30 minutes of increased heart rate
- Intense exercise – 45 to 120 minutes of high heart rate
- Very intense exercise – 2+ hours of increased heart rate
Fat Intake
The quantity and quality (type) of fat you consume also affect the total body fat percentage.
Generally, 20 to 35% fat content in total daily calorie intake is recommended, along with 10 to 35% proteins and 45 to 65% carbohydrates. This is based on the recommended total calories, which are 2000 for women and 2500 for men.
If your fat intake exceeds the ideal limit, it will naturally cause an increase in body fat percentage.
Here is the fat content in common sources of fats:
- 100 gm Oil – 100 gm fats
- 100 gm Nuts – 3.5 gm fats
- 100 gm Meat – 3.5 gm fats
- 100 gm Fish (salmon) – 12 gm fats
- 100 gm Butter and margarine – 81 gm fat
It is also crucial to remember that proteins and carbs that are not immediately utilized by the body are converted to fats in the liver. Therefore, excess calorie intake without a proportional increase in activity level will cause a rise in body fat percentage.
It is important to mention that accurate fat recommendation varies for different individuals based on age, gender, current weight, height, fitness goals, etc. Therefore, for a better estimate of your fat requirement, a fat intake calculator is recommended.
After the quantity of fat, the quality of fat also determines your body fat percentage. As we have already discussed, consuming unhealthy fats (saturated fat) can lead to increased LDL cholesterol in the blood, which is associated with obesity, and heart disease.
In contrast, unsaturated fat is healthy and does not cause unhealthy weight gain.
Measuring Body Fat In US Army Body Fat Calculator
An army body fat calculator uses a US Navy method to measure body fat percentage.
In the US Navy Method, separate formulas have been devised based on gender:
Body Fat Percentage (BFP) For Men
BFP = 86.010 × log10 (abdomen – neck) – 70.041× log10 (height) + 36.76
Body Fat Percentage (BFP) For Women
BFP = 163.205 × log10 (waist + hip – neck) – 97.684 × (log10 (height)) – 78.387
In the above equations, all the measurements will be in inches (as per the US customary system).
The calculated body fat percentage in the US army body fat calculator can be used to calculate fat mass and lean mass.
Fat mass = body fat x weight
Lean mass = body weight – fat mass
As per the US army standards of medical fitness, body fat percentage should be 23% for male recruits, and 34% for women. An army body fat chart has also been developed for different age groups.
Here’s how you can measure the different values required in the equations with a measuring tape:
Waist Measurement
In men, waist circumference should be measured around the navel (belly button) at a horizontal level.
On the other hand, women take waist size at the point of the smallest width around the belly button.
When taking the measurement, person should be standing upright, looking straight ahead.
Neck Circumference
Neck circumference should be measured below the larynx (adam’s apple). When doing so, make sure your neck (adam’s apple) is not protruding outwards.
Hip Measurement
For hip measurements in women, consider the largest horizontal measure.
Abdomen Circumference
To measure the abdomen circumference, locate the upper side of the hip bone and the top of the iliac crest. Next, place a tape at the level of the iliac crest in a horizontal plane.
Make sure that your tape is parallel to the floor and does not compress the skin.
Maximum Body Fat Percentage
Maximum body fat percentage refers to the ideal levels of body fat.
According to the American Journal of Clinical Nutrition, the army body fat formula is as follows (based on gender and age group):
For Men
- Aged 20 to 39 – 8% to 19%
- Aged 40 to 59 – 11% to 21%
For Women
- Aged 20 to 39 – 21% to 32%
- Aged 40 to 59 – 23% to 33%
If your fat content is not within the ideal range per the army method, it is an indication of poor health.
Army Body Composition Program
Being in military requires you to deliver best physical performance, for which having healthy body fat percentage is important.
As per the army method, service members recruited in US army are regularly evaluated for body fat as part of the army body composition program.
Anyone who needs to decrease body fat percentage per the body fat formula is required to follow a strict schedule involving resistance training and other activities.
Harmful Effects Of Low Body Fat Percentage
Body fat is essential for several reasons, like:
- Energy Reserve: Fats are one of the most efficient energy sources, as 1 gm of fat yields nine calories, which is more than twice what an equivalent amount of other macros produce.
In case of calorie deficit, stored body fat is broken down by the liver into ketone bodies which supply the required energy. This energy is essential for survival, which is why ensuring adequate fat intake is crucial.
- Vitamin Absorption: Fat-soluble vitamins (A, D, E, and K) need adequate body fat for absorption. These vitamins are crucial for several physiological body functions like temperature regulation, immune system, sexual activity and fertility, and maintenance of the health of vital parts and organs like bones, lungs, heart, eyes, etc.
Lower body fat percentage leads to malabsorption of these vitamins, which eventually causes severe health complications.
- Cognitive Development: Omega-3 and Omega-6 (essential fats) are crucial for brain development and are found in fatty fish, fish oils, and other healthy fat sources.
Low intake of these two essential fats can lead to cognitive disability, especially in children and young adults.
- Immunity: Body fat helps build immunity by increasing the number of T-helper cells (a type of immune cell). Therefore, lower body fat percentage increases your chances of developing infections and other diseases.
- Sexual Activity: Sexual activity and fertility are regulated by special hormones (estrogen, testosterone, prostaglandins). Fat acts as a precursor for these chemicals, which is why low body fat can result in decreased libido, and infertility.
Harmful Effects Of Obesity
Like low body fat percentage, excess fat (obesity) is also associated with health complications like:
- Heart disease (atherosclerosis)
- Gallbladder disease
- Kidney stones
- Metabolic syndrome
- Diabetes mellitus (type 2)
- Respiratory distress
- Fatigue
- Death
