What is BMI and Body Fat Percentage?

A basic guide on health has long since been the BMI index. It means body mass index and is meant to be a quick reference guide that allows you to see how in or out of shape you really are. However the BMI scale was first created somewhere between 1830-1850 Belgian polymath Adolphe Quetelet. Originally physicians used it to calculate how much sedative could be used on a patient.

Today it is a vague measure on whether a person is overweight or underweight. This is a guide based on your weight (in kgs) divided by your height squared (in meters). This does not take into consideration your bone density or muscle mass. A body builder may have a high BMI but it is not because they are “overweight” or carrying too much fat. Generally it can be used as a quick rule of thumb measurement for overall body mass. A normal BMI on average is 18.5-25 however many people may appear to be the wrong weight because it does not take into consideration other factors.

Use the BMI as a rough and vague way of quickly measuring what kind of shape you are in. And round does not count as a shape…

bmi graph


Anyone who has largely high or low scores should seek medical advice before embarking on a new eating plan.

Body fat percentage is a more accurate reading of your mass. It is a separation of your pure fat (adipose tissue) from the mass of your bones and organs. Levels of fat differ for age and gender. Infants or older individuals will carry more fat percentage. Females are also prone to carry higher fat amounts due to the metabolic needs of supporting pregnancy.

When it comes to actual body fat measurements, it is a far better indicator of health than the BMI. Measurement techniques may be subject to some error. The more accurate tests tend to be very pricey however, thus many people will not use them.

Having fat in your body is essential for growth and maintenance of all cells. Below is a table describing different percentages of body fat and what it means for your health. A fat percentage lower than the “essential level” can have as many negative health effects as being considered overweight or obese.

body fat percentage* Essential fat is the smallest level in the body we should have before we suffer from health problems. In the case of women, too little body fat can lead to menstrual problems and/or sterility.


fat percentage idea

Body Fat Measuring Systems

Underwater weighing

With a well engineered weighing system, body density can be determined with great accuracy by completely submerging a person in water and calculating the volume of the displaced water from the weight of the displaced water. A correction is made for the buoyancy of air in the lungs and other gases in the body spaces.

Estimation of body fat percentage from underwater weighing (or hydrostatic weighing) has long been considered to be the best method available, especially in consideration of the cost and simplicity of the equipment. Most other ways to estimate body fatness, such as by skin folds, body girths, body impedance, air displacement volume and body scanners are based on equations which predict body density. In contrast, underwater weighing gives an actual measurement of body density rather than a prediction.


Bioelectrical impedance analysis

The general principle behind BIA: two or more conductors are attached to a person’s body and a small electric current is sent through the body. The resistance between the conductors will provide a measure of body fat between a pair of electrodes, since the resistance to electricity varies between adipose, muscular and skeletal tissue. Fat-free mass (muscle) is a good conductor as it contains a large amount of water (approximately 73%) and electrolytes, while fat is anhydrous and a poor conductor of electric current. Factors that affect the accuracy and precision of this method include instrumentation, subject factors, technician skill, and the prediction equation formulated to estimate the fat-free mass.

Each (bare) foot may be placed on an electrode, with the current sent up one leg, across the abdomen and down the other leg. (For convenience, an instrument which must be stepped on will also measure weight.) Alternatively, an electrode may be held in each hand; calculation of fat percentage uses the weight, so that must be measured with scales and entered by the user. The two methods may give different percentages, without being inconsistent, as they measure fat in different parts of the body. More sophisticated instruments for domestic use are available with electrodes for both feet and for both hands.


Skin fold measurements

The skin fold estimation methods are based on a skin fold test, also known as a pinch test, whereby a pinch of skin is precisely measured by calipers at several standardized points on the body to determine the subcutaneous fat layer thickness. These measurements are converted to an estimated body fat percentage by an equation. Some formulas require as few as three measurements, others as many as seven. The accuracy of these estimates is more dependent on a person’s unique body fat distribution than on the number of sites measured. As well, it is of utmost importance to test in a precise location with a fixed pressure. Although it may not give an accurate reading of real body fat percentage, it is a reliable measure of body composition change over a period of time, provided the test is carried out by the same person with the same technique.

Skin fold-based body fat estimation is sensitive to the type of caliper used, and technique. This method also only measures one type of fat: subcutaneous adipose tissue (fat under the skin). Two individuals might have nearly identical measurements at all of the skin fold sites, yet differ greatly in their body fat levels due to differences in other body fat deposits such as visceral adipose tissue: fat in the abdominal cavity. Some models partially address this problem by including age as a variable in the statistics and the resulting formula. Older individuals are found to have a lower body density for the same skin fold measurements, which is assumed to signify a higher body fat percentage. However, older, highly athletic individuals might not fit this assumption, causing the formulas to underestimate their body density.


7 reasons you aren’t losing weight

obese child

I’m going to make an assumption about you, which I know is the wrong thing to do. But humor me for a moment. I am going to believe you are the person who:

  • Tries their best to eat healthily
  • Has tried many types of exercise.
  • Has considered taking weight loss supplements, or you already have taken some.
  • Despite everything, sill cannot lose that stubborn fat.

There are many resources dedicated solely to the pursuit of weight loss. We have diet plans and videos. We have supplements, bars, meals and shakes. We have websites, magazines and books. We have personal trainers, nutritionists and public gyms. Despite all of these ‘things’ you can’t lose that stubborn fat and nor can most of the people you know. Before you scroll down in a hurry to find WHY you can’t lose weight, please pause a while for a little education.

Health is NOT the numbers on a scale. The average scale is mostly inaccurate by as much as 10%, that’s about 6kg you may have added or subtracted erroneously. You need to take into account that muscle weighs more than fat, therefore you may weigh the same after a gym program but your body composition is totally different. Therefore it is best to rather not base your health on one single measurement, especially your pure mass.

I insist rather for you to have a full health check-up to better determine your health level. It offers greater insight into how you are progressing on a month to month basis. These tests are normally done by a professional and are subject to less errors than home measurements. A professional can also interpret your data into something you can better understand. So when wondering why you aren’t losing weight, rather use all of these measurements about once every 3 months to gain a better view on your real health level.

  • The circumference of your upper arm and thigh, as well as your hip and waist measurements. These can be a guide to centimeter loss. Effective weight loss programs will reduce your overall ‘size’ but sometimes it also negatively affects your muscle mass too.
  • Blood pressure indicates the force that your blood flows through your veins. If you are unfit, overweight, sick, unrested, stressed, or suffering from a metabolic syndrome then high blood pressure is the warning signal. it should read 120 over 80 in normal situations.
  • Body mass index. (BMI). It was originally a standard used to guesstimate the amount of anesthetic a person required for surgery. It is your weight in kgs divided by your height squared. A normal figure is between 18.5 to 25. Lower than that you are too light for your height. Higher than that you are too heavy for your height. This however isn’t an entirely accurate calculation and can be subject to errors.
  • Body fat percentage. This is the sheer mass of your total body fat in relation to your entire mass. This is by far one of the better ways to gauge your health and weight loss program. It is measured with calipers, electrical impedance devices or special water tanks. Women are meant to have more fat than men for birth purposes. A normal measurement for a man is between 14-18% where a woman is 18-24%.
  • Glucose levels. The best way to test it is with a finger prick test in the morning before you have eaten anything. Abnormal levels are an indication of diabetes or insulin resistance, which are very good reasons as to why you aren’t losing weight.
  • Cholesterol testing. It requires a blood sample from you, preferably in the morning before you have eaten. It can tell you if you have too much ‘bad fat’ in your veins. High readings can be an indication of you being unfit, overweight, sick, stressed, or suffering from a metabolic syndrome.
  • Then finally the very last measurement is your overall mass. Your body weight should always be measured on the same scale at the same time of day in the same type of clothes for more accurate results.

So now down to the nitty gritty. The reasons you may not be losing weight. Some may seem strange to you but they most definitely have an effect on your ability to reach your goal. Ask yourself the following questions to pinpoint where it is that you may be going wrong.

  1. Are you taking weight loss supplements? If so, stop it now. Throw that junk away. You did not get fat by not taking those pills, therefore those pills will not make you skinny. There are many harmful chemicals in there you may not know about. No supplement is monitored or regulated. Even so-called natural products can be rather sinister. The main problem here may not even be the supplement itself. The desire to take a supplement is you being stupid enough to have a standard of beauty dictated to you by the very people who make money off of what makes you “beautiful”.
  2. Are you exercising? NO? Well I’m afraid that answer is incorrect. You did not win the corvette behind door number one. Exercise reduces depression, staves off disease, increases insulin resistance in the body, improves the body’s hunger response and reduces the fat-storage mechanism’s ability to store fat.
  3. Are you doing hours of exercise to lose weight? Again, wrong answer. You don’t even get the consolation prize as we lead you off set. If you want to lose weight you need to pack on the muscle big time. Muscle requires more energy to maintain than fat. Therefore when you eat more food will go to your muscles than your butt. The higher your muscle mass, the less fat your body makes. Therefore when you reduce your overall food intake your body will start eating into the fat reserves. You need to pump the iron for this to happen. And the easiest way is through HIIT, high intensity interval training. This is common in Crossfit, body building, sprint training and other high-power sports.
  4. Are you drinking sports drinks? Stop that right now. Drop the sugar and walk away. It has been proven that sugar causes obesity, high blood pressure, depression, diabetes and other metabolic syndromes. Only athletes need some sugar to rapidly replenish their depleted muscle glycogen stores. Unless you are an athlete in training you need to cut ALL sugar out your diet. This is the hard part. Sugar is in bread, gravy, soup, biscuits, pastas, sauces, spices, sweets, chips, drinks, coffee creamers, cereals, health crackers and more.
  5. Are you planning to lose weight? Because unless you are aiming at a target you will just fire your arrow in any direction. There is no telling what you may hit. You must plan to lose the weight. You can’t just be a wandering generality. You must become a meaningful specific. Set a SMART goal once you have measured the parameters of your health. Specific: I will get to my ideal weight according to the doctor. Measurable: X weight and X body fat percentage, both figures on paper. Achievable and Realistic: Your doctor should believe that he goal you want is realistic and achievable for your circumstances. Time-bound: Make a date in accordance with the time frame your doctor believes your goal should be achieved in. Write the date where you can see it. Bind yourself to that date. But remember there will be setbacks. Don’t throw a tantrum or give up if you did not achieve your goal.
  6. Are you thinking like a fat person? This may seem odd, but you are very used to your lifestyle. You have gotten used to the stares of contempt. You are used to digging in the back of clothes racks only to be disappointed that they do not have your size, again. Your entire time spend overweight has become your life and the whole experience is burned on your brain. Before you lose weight and become that skinny person, you have to live like one. Too fat to go jogging? Well that’s why you are fat. Skinny people jog so should you. Too fat to do anything but watch TV and hide behind baggy clothes? Skinny people get off their asses and they wear clothes that suit their frame, so should you. Stop hiding behind the fat man. You gotta act like a skinny person to be one.
  7. Keep making excuses for yourself? Well there’s the problem mister. Your car won’t go coz somebody done stole your engine, yessiree. Too cold, too dark, too hot, to early, too late, too tired. I can’t right now. My dog is sick. Soon as I get this promotion. The second the new week/month/year rolls around I swear it will be different. Sound like you? Well that’s the number one reason you are still fat. You want to lose weight, but only kinda want it. You are obsessed with health, but not in the ‘gym 24/7’ way. More like the ‘use binoculars to stare at Miss Health through her bedroom window’ kind of way. You have got to want health more than you want to sleep. You have got to want health more than you want to party. If you really wanted to be healthy you’d not get upset when someone offered you unhealthy food. Because you would want health more than the glazed donut which is now staring at you. Health and weight loss is not chance, it is a choice.

If you can change these seven factors you should have removed the major obstacles in your path on the way to weight loss. Remember this is still no guarantee. You have to work hard, exercise enough and in the right way, sleep enough and eat correctly. There is a lot that goes into being healthy. But stop sabotaging yourself before you even start.