Can Using A BMI Calculator Help Me Lose Weight? Are BMI Calculators Accurate?

Written by Liza Brunell

Adv Dip Health Science Naturopathy, Nutrition          Hi there, my name is Liza, I am a Naturopath, Herbalist, Nutritionist from Brisbane, Queensland. And I’m here to show you how easy good nutrition and healthy living can be.

March 30, 2020

Navigating around the world of weight loss can be completely overwhelming, it seems that everyone has an opinion! This leaves you even more confused and unsure of which road to take that will be the best fit for you. So, how is it that you can determine something as simple as how much weight do, you need to lose to be in a healthy weight range?

I’ve put together some information that may be useful in determining what is considered a healthy body weight to make your life a little easier. Let’s start with looking at the universally used:


What Is The Body Mass Index (BMI)

Body Mass Index is a general tool that has been used for years to determine a healthy or normal body weight.  What the BMI is doing is assuming what would be considered a ‘normal’ body weight for both men and women of average height and average fitness or activity level. For example:  The simple BMI calculation is this equation:

Body Mass Index = Weight (kg) / Height (m) ².

There are also several BMI calculators that can be found online such as the Australian govt department of health BMI calculator.

BMI calculations have been used since the 1800’s and have been widely used after this time to assess not only a normal or healthy body weight but a link between body weight and potential cardiovascular disease risk. So, it raises the question, are BMI Calculators accurate?

In fact, its use has spread across the world to collect data to link BMI to several different health conditions and potential disease risk.  Another reason BMI is still used is that it can be used to compare different groups of individuals and nationalities by calculating their BMI.  This is possible due to its simplicity in that all that is required is a person’s height and weight.

As we all know there is not usually a one size fits all approach when it comes to weight loss as we are all different, right?  So, there are a few issues when it comes to using a BMI calculator.

  1. Not everyone has the same body type.
  2. In general, taller individuals tend to be thinner on average, and their bone mass larger which will affect their BMI result.
  3. A high muscle mass can also result in a higher BMI because muscle is denser than fat also skewing the result.
  4. Above and beyond that a so-called normal body weight will vary for people of differing ages, gender and nationality.
  5. There is no separate BMI calculator for male vs female

Therefore, it is extremely important to take these considerations into account when you are trying to understand your own personal BMI reading.


Considering These Anomaly’s, Why Is The BMI Still Used If Not Accurate?

Despite the limitations mentioned above, ironically these limitations continue to play a part in why the Body Mass Index is still used.  This is for the simple reason that each person is indeed different therefore no single calculation can comprise everyone.

Considering all health index’s will have their limitations, the BMI is still used because it is by far the broadest and simplest index to calculate i.e. weight divided by height squared.


Once You Have Worked Out Your BMI Calculation, What Does It Mean?

For most, according to the Australian govt Dept of health the following applies:

  1. If your BMI is less than 18.5 your BMI is considered to be within the underweight category.
  2. If your BMI is between 18.5 – 24.9, your BMI is considered to be within the healthy weight range.
  3. If your BMI is between 25-29.9, your BMI is considered to be within the overweight category.
  4. If your BMI is 30 or more, your BMI is considered, to be within the obese category.


When calculating BMI, remember that there are always exceptions.  For example, a healthy weight range may be:

  1. Lower in individuals of Asian background
  2. Higher in those of Polynesian origin
  3. Higher in the elderly
  4. Higher for elite athletes with increased muscle mass
  5. Pregnancy will also affect BMI, however, weight gain during pregnancy is only temporary and necessary in the development of a healthy baby


How Many Calories A Day Should I Eat To Lose Weight?

Seeing as the BMI calculations can not always be accurate, it is generally acknowledged, if you combine a 1’200 calorie a day intake with four or five exercise sessions a week, then a 1’200 calories-a-day eating plan will help you reach your weight-loss goals, over time.  The exact amount of weight loss will be different for everyone and will depend on how much weight you have to lose and how much energy is expended during each exercise session.

However, if you prefer to eat fewer calories, and access the rest of your calorie needs by burning up your unwanted stored fat for energy, then I have found The hCG Diet Australia eating plan and homeopathic drops, to be extremely successful for weight loss. The hCG Diet Australia have taken the guesswork out of meal planning and calorie counting, you are given the exact food list of allowable foods along with a weekly meal plan. Exercise is also kept to a bare minimum to give you time to practice self-care while your body accesses your stored fat for energy, eliminates toxins and does general cellular repairs.  You can use this time to plan your weekly meals in advance. They also guarantee that you will lose 5kg-7kg in only 23 days if you stick to the plan.

At first calorie counting can seem complicated and confusing, however, it doesn’t have to be difficult.  There are some great apps available that can help e.g. My Fitness Pal.

It’s also important to keep in mind that women have different calorie requirements to men. Men tend to have more muscle and less fat on their bodies; therefore, they burn more calories throughout the day then women. So, if you are embarking on a dietary program with your partner or a male family member take that into consideration before becoming disheartened that you may not be losing as much weight as they are.

Weight loss can be daunting for anyone and let’s face it we have all tried to either lose or gain weight during our lifetime and most of us will also have a distorted perception regarding our weight and unfortunately tend to compare ourselves to others.

Although it does have its limitations the BMI calculator can still be a useful tool to get an idea of where you fit in the normal to healthy weight range. However, it does still raise the question, are BMI calculators accurate.

It is important to keep focused on the end game, being a healthy weight means that you are at less risk of chronic disease.  You will gain energy, improve your sleep, have less aches and pains, live longer and generally be happier.

Liza Brunell

Adv Dip Health Science Naturopathy, Nutrition
What is The hCG Diet Australia?

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