Body Mass Index, or BMI, is a measure used to determine whether an individual is underweight, healthy weight, overweight, or obese. It is calculated by dividing an individual’s weight in kilograms by their height in meters squared. The resulting number is used to classify an individual’s weight status. While BMI is a simple and widely used method for assessing weight status, it does have its benefits and pitfalls.

One of the benefits of using BMI is that it is easy to calculate and does not require any special equipment. It is also a relatively inexpensive method for assessing weight status. Additionally, research has shown that there is a strong relationship between BMI and health outcomes, with higher BMIs being associated with an increased risk of health problems such as heart disease, diabetes, and certain cancers.

However, there are also several pitfalls to using BMI as a measure of weight status. One of the main limitations of BMI is that it does not take into account differences in muscle mass, bone density, and distribution of fat. This means that someone with a high muscle mass may have a higher BMI, but may not necessarily be at an increased risk of health problems. Additionally, BMI does not account for differences in age, sex, or ethnicity, which can all affect an individual’s weight and health status.

Another pitfall of using BMI is that it can be misleading in certain cases. For example, an athlete with a high muscle mass may have a high BMI, but may not be at an increased risk of health problems. On the other hand, an older individual with a lower muscle mass may have a lower BMI, but may still be at an increased risk of health problems due to the distribution of their fat.

In conclusion, while BMI is a useful tool for assessing weight status, it is important to consider its limitations and not rely on it as the sole measure of an individual’s health. Other factors, such as waist circumference, body fat percentage, and health markers, should also be taken into account when assessing an individual’s weight and health status.

Refer to our BMI calculator on How to calculate BMI to assess what your current BMI is as well as future maintenance.

I’ve always struggled with my weight. I’ve tried countless diets and exercise plans, but nothing seemed to stick. I knew I needed to find a way to track my progress and hold myself accountable, so I turned to the Body Mass Index (BMI) calculation.


BMI Weight Status
less than 18.5: Underweight
18.5 – 24.9: Healthy weight
25 – 29.9: Overweight
30 – 34.9: Obese (Class I)
35 – 39.9: Obese (Class II)
40 upwards: Obese (Class III)

Body Mass Index (BMI) is a measure of a person’s body fat based on their weight and height. It is widely used as a tool for assessing a person’s weight status and determining whether they are underweight, normal weight, overweight, or obese. The BMI is calculated by dividing a person’s weight in kilograms by their height in meters squared.

The World Health Organization (WHO) has defined four ranges for BMI:

  • Underweight: Below 18.5
  • Normal weight: 18.5 to 24.9
  • Overweight: 25 to 29.9
  • Obese: 30 or above

It’s important to note that BMI is not a perfect measure of body fat, as it doesn’t take into account factors such as muscle mass or bone density. People with a higher muscle mass, such as athletes, may have a high BMI but still be healthy. Similarly, older adults or people with health conditions may have a lower BMI but still be at risk for health problems. Therefore, it’s crucial that BMI is used in combination with other indicators, such as skinfold thickness measurements, waist circumference, and body composition analysis, to determine a person’s overall health status.

Additionally, it’s also important to consider cultural and ethnic factors when assessing a person’s weight status, as different groups may have different ideal body types and ranges. Moreover, certain individuals may have certain medical conditions that may affect their weight, such as hormonal imbalances, which may affect the accuracy of the BMI.

In conclusion, BMI is a useful tool for assessing a person’s weight status, but it should not be used as the sole indicator of a person’s health. A combination of different measurements and factors should be taken into account, such as muscle mass, cultural and ethnic factors, and overall health status. Therefore, it’s crucial that healthcare providers interpret and use BMI results in the context of a person’s overall health status.

Body Mass Index (BMI) is a common measure of determining a person’s weight status. It is calculated by taking a person’s weight in kilograms and dividing it by the square of their height in meters.


Before you begin your weight loss journey, you need to first know what your starting point is. This is a hard process because it involves accepting what you currently are, even though you may not be happy with what you see. Standing on the scales for the first time in a long time can be scary, but a vital process because it will give you measurements to compare to as your progress develops. This will also aid as a motivation tool because once you start to notice positive changes, you would have more desire to continue your journey and push even harder. My recommendation would be to perform 3 measurements. Alone they may be a little flawed, but all together will give you some good measuring and goal setting tools.


1. Measure your weight (in lbs or kgs) by standing on a set of scales

A simple and obvious process but a few recommendations worth mentioning.

Note that this will not consider if you are building muscle at the same time so just be aware. You may not lose weight according to the scales but have reduced your overall body fat percentage. This is why other measurements are essential to go alongside this.

Don’t worry if your scales are old and/or inexpensive without fancy features. They might be slightly out, but the main key is to:

i). Make sure that you only use one set of scales throughout your whole journey:

A set of scales at the gym may yield a different result than your set at home under the exact circumstances giving you misleading results, so best to just avoid it altogether.

ii). Measure yourself under the same circumstances each time:

My recommendations are first thing in the morning (before consuming any food or fluid), in the nude and after a no.1 and no.2 (pee and poo if that wasn’t obvious enough for you). This will make sure you have an accurate base to compare to on a consistent basis.

iii). Weighing yourself daily:

If you weigh yourself once a week, it may show a false result if there are any variables with your body i.e. greater amounts of water retention, a late heavy meal the night before, or something similar. This will make you unmotivated if your think you haven’t lost anything after working hard for a whole week and demotivate you, even though it may not be accurate. Going another week to find this inaccuracy out is a long time to have to wait also.

A daily measurement will take away the surprise a little as the results are more gradual, but it will help to get a more accurate moving average measurement, weeding out any day-to-day anomalies over the course of the week.

Tip. There are plenty of free weight recording apps on the market or very inexpensive, to say the least. This will give you a nice graph to help interpret the results better. You can also get scales that automatically feed to data into the manufactures app making it all automatic.

2. Calculate your BMI

For a free BMI calculator or to learn more, refer to our article How to calculate BMI.

What is BMI?

BMI or Body Mass Index is a simple calculation based on height and weight and will help screen for weight categories that could lead to health problems (i.e it will help aid identify if you are underweight, healthy, overweight or obese (I, II and III).

BMI has its flaws also, as it is a measurement relying on your weight also, which may be skewed by several variables as discussed above. The focus here is to keep it simple and use it as a basic score only. I.e if your BMI is 26 (Overweight), it can be a good motivation and goal-setting tool/comparison to get the score down to a healthier range by losing some body fat. Reviewing this on a monthly basis is the best approach in my opinion.

3. Measure your belly and glute circumference with a measuring tape

Although it is possible to measure your whole body, if you are focussed on fat reduction alone, these are the two greatest fat storage areas of our body that will provide the best measurements for this purpose. It will also be far less time-consuming than measuring your whole body making it more sustainable to maintain.

These measurements will aid as a comparison tool and show results in fat loss even if you have not lost weight on the scales. Based on this, it is a great supplement tool. Note that if you are suffering from bloating, consumed meals or fluid and/or have greater fluid retention, this can also be misleading, so minimise your risk of inaccuracy by measuring consistently as mentioned above with your scale measuring. Performing this task on a weekly basis (not daily as with the scale measuring) is the optimum as this area will take longer to display results as compared to scale measuring.