body composition-BMI vs Body Fat Percentage

BMI vs Body Fat Percentage

What is Body Mass Index?

The body mass index, or BMI for short, is a frequently used measure to assess a person’s body weight. Whether normal weight, overweight or underweight – the BMI helps you to correctly estimate your weight and have a better overall look at your body health than just measuring the body weight.

Body mass index correlates with total body fat. This means that as the body mass index stripe increases, so does the total body fat of a person.

How is BMI Calculated?

The body mass index in a person is predicted by employing a mathematical formula. One can also estimate using tables in which height in inches to weigh in pounds can be matched to estimate body mass index. There are handy body mass index calculators available on the internet sites that help predict body mass index as well.

The formula is:

Body Mass Index = (weight in kilograms) divided by (height in square meters)

Body Mass Index Trends in the United States:

According to the book, a person having a body mass index of above 30 kg/m2 can be regarded as obese. Based on this formula, a large chunk of the adult population of the United States falls into the obese category.

In 2014, more than 37 percent of the adult population of the United States was regarded as obese by its body mass index trends. Out of this chunk, about 35 percent of the men and 40 percent of the women had obesity on their diagnoses. Moreover, 7 percent of the men and 9 percent of women had body mass indices of above 40, which is classified as class 3 obesity. (1)

Why is BMI used to measure overweight and obesity?


The connection between BMI and health is influenced by many other factors. A BMI from 25 to 30 is medically defined as being overweight. But studies show that a BMI of this magnitude does not have a major impact on life expectancy and various diseases. Obesity is particularly important for health when other diseases such as diabetes exist at the same time.

A BMI value between 25.0 and 30.0 can indicate overweight; this is referred to as an increased BMI. Since the BMI does not differentiate between muscle and fat mass, this limit can also lead to incorrect classifications. For example, people who do weight training or do extreme physical work are often incorrectly considered overweight according to the BMI, as muscle mass is generally heavier than adipose tissue.


A body mass index of over 30.0 indicates obesity, that is, pathological, severe overweight. Obesity can harm health and life expectancy. The more pronounced the obesity, the higher the risk of concomitant diseases such as high blood pressure, lipid metabolism disorders, cardiovascular diseases, diabetes mellitus, and psychosocial problems. (2)

It is undisputed that obesity (BMI over 30) can have a negative impact on health and life expectancy. Here, too, it depends on the overall picture in individual cases. There are certainly people with obesity who are fit and have a healthy cardiovascular system. For them, weight is not necessarily a health problem. However, many obese people improve their health if they manage to lose some weight.

In addition to body weight, the risk of cardiovascular disease, in particular, depends on many different factors. Above all, these include age, gender, blood pressure, cholesterol levels, family predispositions, diabetes, and smoking. It is, therefore, useful to consider the health implications of obesity concerning other risk factors.

Body Fat Percentage vs Body Mass Index:

The body fat percentage indicates the percentage of adipose tissue in your body concerning its total mass. The percentage of body fat that is good depends largely on your age and gender. Body fat can have major effects on our overall health. Having excess body fat can elevate the risks of developing hypercholesterolemia, which is a state where the body has abnormally elevated levels of cholesterol. Having elevated levels of cholesterol can lead to increased risks for myocardial infarctions or strokes. (3)

What is Ideal Body Fat Percentage?

Body fat percentage should be kept within the normal range. If the body fat percentage is too high and the body weight is more than 20% of the ideal body weight according to the Body Mass Index, it can be regarded as obesity. The body fat percentage of normal adults is 18%-34% for men and 25%-31% for women. However, many factors affect this range such as diet, lifestyle, and athletics. (4)

Body Mass Index vs Body Fat Percentage:

Body Mass Index (BMI) is most often confused with the term body fat percentage. However, both of these terms are very different. Body Mass Index says nothing about the stature and the ratio of body fat to muscle tissue. Because of their larger muscle mass, athletes often have a higher BMI value, but they are not overweight. Many slim women can be called “skinny fat” because they are thin, but hardly have any muscles – and are therefore not fit. Therefore, in addition to the BMI, the body fat percentage is becoming increasingly important as a formula for evaluating weight and health.

The Body Mass Index (BMI) is a commonly used measure by physicians to estimate the total fat content in your body. It is also very easy to calculate. Dividing your body weight by the square of your height gives you the BMI.

On the other hand, your body fat percentage is essential for knowing the total fat content of your body concerning other macronutrients. It divides your total weight into two categories: body fat and everything in between. Having a normal amount of body fat is needed for the basic metabolism of the body and helps the body warms itself up. (5)

Why Does my Body Fat Percentage Not Change?

Grinding hard to lose body fat is one of the best methods to keep your body fat percentage in check. However, sometimes, the body fat percentage still does not change despite exercising regularly. This means that there are some irregularities in your schedule which are responsible for this phenomenon:

1. Eating too much:

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The World Health Organization (WHO) estimates that around 25 percent of all people worldwide are overweight or even obese. In the case of adults, it is even more drastic, here almost 40 percent are at least overweight.

Some people do not feel full despite having a whole meal. Scientists have long assumed that the “satiety hormone” leptin is responsible for this. It was thought that it did not reach the brain in sufficient concentrations in overweight people. In the meantime, however, it has been shown that there are no differences between slim and fat people. The cause of the lack of satiety must therefore lie in the nerve cells, which causes the people to eat more, therefore more food content is converted into fat which can stain your grinding routines to lower your body fat percentage.

2. Drinking:

Many people still do not know what alcohol does inside their bodies and how it can affect their ability to burn fat. It slows down the body’s fat-burning process by 73% and reduces the effect of leptin, a hormone that tells the brain to stop eating. (6)

Once consumed, alcohol (which is ethanol) breaks down into acetaldehyde and something called nicotinamide adenine dinucleotide (NADH) by the enzyme alcohol dehydrogenase (ADH). It is this very process that triggers adverse changes in nutrient storage and body composition.

3. Not Training Intense Enough:

Exercise is essential for not only maintaining the skeletal system of the body in perfect condition but also supporting many physiological processes in the body. However, exercising properly is more important than exercising regularly, as this helps to burn fat at a more consistent rate.

4. Stress:

Stress, whenever a person is faced with an unimagined situation or thought, can trigger alarms in the brain that tells the nervous system to release hormones to sharpen the senses, tender muscles, quicken the pulse, and breathe deeply. Isolated or temporary stressful situations can be harmless, but regular exposure to stress can lead to many problems which also include obesity. The hormone cortisol is responsible for the deposition of the fat in the abdominal area, which results in increased body fat percentage despite the daily grind to burn down fat. (7)

5. Lack of Sleep:

Sleep deprivation tends to decrease the glucose tolerance in a person’s body, which is the body’s ability to metabolize ingested glucose to restore normal blood sugar levels. Not having enough sleep also influences the regulation of appetite through leptin, which is the hormone responsible for reducing food intake when the stomach is full. People who lack sleep are less likely to be physically active, therefore their energy expenditures are decreased greatly. Decreased energy expenditures and alterations in the secretion of leptin hormone contribute to the increased body fat percentage. (8)

Body Fat Percentage and Body Composition:

You’re Working Out, But Body Fat Percentage Remains the Same:

Exercise alone is not a guarantee of success when it comes to losing weight. The more you move, the more calories you burn and the weight goes down. But it is not that simple. If you only focus on sport and do not change anything in your diet, you will be disappointed. 30 minutes of exercise on the treadmill burns just 350 kilocalories, which is roughly the equivalent of a candy bar. This means that if you are grinding every day to burn body fat, and also have a diet that is full of calories, the fat will continue to deposit and you will not see any satisfactory results until you take your diet seriously.

You're Losing Weight, But body fat percentage stays the same:

Losing weight is not an easy task, many people have to grind for months and months before they start noticing a difference in their body weight. However, most of the people who are on weight-losing routines have one main purpose in their minds, to lose that unwanted fat from their bodies. This results in a decreased body fat percentage.

However, there are many instances where people are successful in losing kilograms, but the relative body fat percentage does not change. It means that your body fat is not burning efficiently enough. The body fat percentage is decreasing, but the decrease is proportional to the decrease in the total body weight. Losing fat more efficiently requires radical changes in diet and exercise routines.

Body Fat Percentage is OK, But You Are Underweight/ Have Muscle Imbalances:

Many people face the issue when their body fat percentages are ok but the weight scales classify them as underweight. This simply means that the bodyweight is not proportional. The portion of body weight supposed to be made of fat is there, but the bodyweight due to the muscles and other organs is decreased. In this case, the situation suggests that the body needs a more protein diet to build up the muscles and make up for the weight that is made up of muscles and organs.

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In these circumstances, people need to contact a competitive dietician to enact customized diet plans according to the needs of their bodies. The protein content of the diet of such people needs to be adjusted according to the differences in their body weights comprised of fats and proteins.

Paying Attention to body composition:

Body composition analyzer can help know more about health conditions. A balance between fat and lean mass is important for a healthy body. Higher body fat percentages have been linked to an increased risk of things like cardiovascular disease, diabetes, and high blood pressure.

On the other hand, too little body fat can also have harmful consequences for health and lead to hormonal imbalances, a loss of bone density, and a weakened immune system.

For these reasons it is important to know how your body is composed. Without this knowledge, it is difficult to take the necessary steps to keep the body healthy. Body composition analysis is also a great way to track progress in weight loss or weight training programs. In general, the composition can be a more accurate indicator of weight as it takes into account the actual components of body weight rather than just weight in general.


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  2. Defining Adult Overweight and Obesity. gov. (2021). Retrieved 22 November 2021.
  3. Abdominal obesity and your health – Harvard Health. Harvard Health. (2021). Retrieved 22 November 2021.
  4. Ideal Body Fat Percentage: For Men and Women. Healthline. (2021). Retrieved 22 November 2021.
  5. BMI vs. body fat: Which number is more important?. (2021). Retrieved 22 November 2021.
  6. com. (2021). Retrieved 22 November 2021.
  7. van der Valk, E., Savas, M., & van Rossum, E. (2018). Stress and Obesity: Are There More Susceptible Individuals?. Current Obesity Reports, 7(2), 193-203.
  8. Cooper, C., Neufeld, E., Dolezal, B., & Martin, J. (2018). Sleep deprivation and obesity in adults: a brief narrative review. BMJ Open Sport & Exercise Medicine, 4(1), e000392.