This article is aimed at adults, as determining target weight for people who are still in development is different and can be tricky.
Silly as this might sound, your target weight depends on your current weight.
If your Body Mass Index (BMI) is anywhere in range from 18.5 to 25, it means your body mass is normal and it is not necessary to make any changes. Yes, it’s a wide range, but it is due to large individual differences between people. Some people have larger bones, some have stronger muscles, some are naturally very lean, and some are a little plumpy… which, ultimately, can all be normal. Your weight is right weight for you as our body naturally tries to find some equilibrium. So your current weight is also your target weight as long as you’re in that range, which means you don’t need to make any changes to your weight.
If your BMI is between 25 and 30, first of all you should consult with your doctor and use judgement to determine if you should try to lose weight at all. In many cases this range can still be healthy and there’s no much reason to mess with your nutrition. This is especially true for a lower end, around 25-27.
If, however, you do decide to lose weight, your target weight should probably be the one at which your BMI is 25. This particular value of BMI – 25, is associated with very low mortality and morbidity.
So how to calculate your weight at BMI of 25?
The formula for BMI is:
BMI = body mass (kg) / square of height (m2)
If you want to determine body mass at a given BMI, the formula is:
body mass (kg) = square of height (m2) * BMI
So, for example, if you are 180 cm tall, and you want to calculate your body mass at BMI of 25, first you turn centimeters in meters, so it’s 1.8 m. And you calculate like this:
body mass = 1.82 x 25
body mass = 3.24 x 25
body mass = 81 kg
So if you’re 180 cm tall, your target weight should be 81 kg, but only if your current BMI is over 25 (if it’s under 25, there’s no need to gain weight to reach 25) AND if you decide that you need, indeed to lose weight.
If your current BMI is 30 or over, then your target weight can fall anywhere in range that results in BMI from 25 to 30, the higher your current weight, the higher the target weight as well.
So if your current BMI is, for example, 42, it can be quite sensible decision, to choose as a target weight the one that will give you a BMI of 27 or even 28.
However, I personally wouldn’t recommend choosing a BMI over 27 as a long term target goal.
For most of the people a weight that gives them BMI of 25 to 26 is the sweet spot.