A healthy weight

How is the BMI calculated?

The BMI is calculated by using the formula: Weight (kg)/ Height (m)2

For example, if your weight is 64kg and your height is 1.65m
BMI = 64/1.652
BMI=23.5

You can also refer to our BMI calculator on the landing page of the e-Care website.

This will give you a result usually ranging from 15 to 40kg/m2. The BMI measures your relative “fatness”. The BMI is a guide to work out what the “ideal” weight for someone of your stature would be.

Why use the BMI?

The BMI provides a standard tool with which to measure the relative weight of populations. A weight on its own is of little use in determining whether someone is overweight or not. Measuring your BMI can be helpful in measuring not only if you are overweight or not, but also how much weight you would need to lose to reach a “normal” or healthy weight.

The BMI “normal” range doesn’t really indicate what is normal. 60% of the world’s “normal” population is overweight or obese. One could say that it is normal to be overweight! “Normal” in this sense indicates what population studies have found to be the ideal weight to reduce your risk of heart disease, stroke, cancer and other conditions related to being overweight.

Is the BMI always accurate?

The BMI is not always accurate. For example, studies in S.E. Asia have shown that a much lower BMI would be recommended in an Asian population. In fact a BMI over 23 would be “overweight” in such a population, predisposing the individual to the health risks associated with being overweight.

The BMI is also inaccurate in body builders and athletes. Such individuals may have a relatively high BMI due to the amount of muscle they carry, but this does increase their risk of heart disease or stroke. The BMI in this case would need to be used in conjunction with another measurement such as the body fat percentage to be more accurate.

The BMI is used across entire populations as a screening tool to measure weight. There is a certain amount of individual variation within any population. For you, having a BMI of 26 or 18 may be healthy. However, while such minor differences may be accounted for, it is generally agreed that a BMI above 30 or below 15 is simply not healthy – no matter how much individual “variation” might be accepted.

Setting goals using the BMI

If you would like to set a goal to gain weight or lose weight using your BMI as a guide you can do so by using the calculation:

Target weight = Ideal BMI X height (m)2

For example, you are currently overweight, weighing 74kg. You are 1.67m tall. What would your “ideal” healthy weight be? How much weight do you need to lose to reach this?

Target weight = 25 X 1.672
Target weight = 69.7kg
Weight loss goal = 74-69.7kg
Weight loss goal = 4.2kg

Using the BMI you can set safe and realistic goals for your weight that are based on health rather than simply image consciousness.