Optimum weight definition
Optimum weight definition
Find out why your weight and health are about more than your BMI
Does the optimum weight definition for humans really exist?
Do you want to define your own optimum weight as a weight management goal?
Can you really pop certain stats in a calculator and come up with the exact weight you should be to enjoy the peak of health?
What do we mean when we talk about ‘optimum weight’?
The word optimum means “most conducive to a favourable outcome; best” but how does this really translate in terms of our weight?
Surely, the most favourable weight is that at which we are able to live a healthy, fulfilled and long life, but this will look different to different people.
How athletes perceive optimum weight
Athletes and sports professionals often have a clear number for their optimum weight but this is based on knowing the weight at which they are able to perform their sport to the best of their ability.
A heavyweight boxer, for example, would typically need to weigh more than the average person on the street of the same height in order to win in the ring. The same goes for a rugby player who needs muscular strength and power to succeed in the scrum.
On the flipside, the optimum weight of a gymnast or jockey would be much lower than someone of a similar height and build who doesn’t compete in those sports.
Defining our optimum weight is arguably more of a grey area for those of us who aren’t concerned about sporting performance.
The optimum weight definition for non-athletes
In everyday life, the idea of optimum weight refers to the weight someone should be, on average, based on their height, sex, bone structure, body type and the size of their muscles.
Why are these factors important?
Height
Generally speaking, the taller someone is, the larger their skeleton. This means that our optimum weight has to factor the weight of your bones as part of the figure.
However, there are some issues with this. Most significantly, healthy bones tend to weigh more because they’re denser than less healthy bones. Our bone density can be influenced by diet – calcium and Vitamin D both improve bone health – and whether or not you regularly do weight-bearing exercise.
Sex
Men and women have a different body composition. For example, women tend to have a higher percentage of body fat than men throughout their lives, while men often have larger skeletons and greater muscle mass.
Hormones drive fat to be distributed around a woman’s pelvis, bottom and thighs. This is physiologically helpful to women during pregnancy and when breastfeeding because the fat provides vital energy resources to support a growing baby.
Of course, the frustration is that these stubborn areas of fat can persist throughout a woman’s life and contribute to issues such as cellulite.
Men, on the other hand, tend to carry extra fat around the abdominal region. There are no known physiological reasons or benefits for this.
When considering someone’s optimum body weight, we have to consider their biological sex.
Bone structure
Simple optimum weight calculations and calculators often fail to consider a person’s bone structure.
We humans fall into one of three broad body type categories (known as somatotypes), although there is a great deal of variation and crossover, thanks to the complexity of our genetics.
Ectomorphs tend to have long, narrow bones and a delicate frame. Thanks to their faster metabolism, they may struggle to gain weight. Being an ectomorph is perfect for a runner, basketball player or fashion model.
Endomorphs typically have a wider body and store more muscle and fat than other body types. With a slower metabolism, endomorphs gain weight more easily but are also the most physically strong.
Mesomorphs sit somewhere between ectomorphs and endomorphs. This body type tends to be lean but muscular and find it easier than others to build up muscle.
According to Dr William H Sheldon who introduced the concept of body types in the 1940s, it is possible to be a combination of two somatotypes.
For example, you could have an ectomorph’s upper body – i.e. narrow and delicate – with an endomorph’s lower body, prone to gaining weight. We usually hear people describing ecto-endomorphs as “pear-shaped”.
Conversely, an endo-ectomorph body type is “apple-shaped”, i.e. typically long and lean in the lower body but prone to gaining weight around the tummy.
Muscle size
Your optimum body weight will be influenced by the size of your muscles. The more muscles you have, the more they will weigh.
Other factors
As we discussed in our recent blog, 11 factors that affect weight loss, your optimum body weight will also be affected by factors such as your genes, age, race or ethnicity. For example, a World Health Organisation consultation back in 2004 suggested that Body Mass Index (BMI) cut-off points for determining when someone is overweight or obese may not be appropriate for Asian populations who seem to have a higher risk of developing type II Diabetes or cardiovascular disease at a substantially lower BMI than people from European populations.
Optimum weight doesn’t just come down to measurable physical factors. It’s important to recognise that cultural attitudes and trends can influence how we see our ideal body shape and may not always be realistic or healthy.
From a medical standpoint, the word “optimum” is what’s important – the weight and physical health that will give you the most favourable outcomes in life, in terms of wellbeing, disease prevention and a long life well lived.
What is the Body Mass Index (BMI)?
At the moment, one of the most widely used measures of a person’s optimum weight range is the Body Mass Index (BMI).
The BMI calculation divides an adult’s weight in kilograms by their height in metres squared.
For example, the BMI calculation for someone weighing 68kg (roughly 10 and a half stone) and measuring 165cm (approximately 5’5”) in height would be 68 ÷ (1.65 x 1.65), giving a BMI score of 24.98.
Using this system, if your BMI is:
below 18.5 – you're in the underweight range
between 18.5 and 24.9 – you're in the healthy weight range
between 25 and 29.9 – you're in the overweight range
between 30 and 39.9 – you're in the obese range
Although the index does take sex and body type into account to a certain extent, it isn’t able to fully encompass the multiple factors that would influence the optimum weight definition for every individual.
Other ways to define your optimum body weight
There are a number of other methods that people use to calculate someone’s optimum body weight.
Many of these focus on identifying and measuring body fat or body fat percentages.
Contrary to popular opinion, body fat is not the enemy when it’s at a healthy level; in fact, it’s essential to our survival. It’s when we have too much or too little body fat that we can be at risk of developing debilitating diseases such as cancer, type II diabetes, heart disease, strokes and more.
Methods to measure body fat include:
Skin-fold calipers that measure the amount of pinchable skin at key points on the body
Bio-Electrical Impedance Analysis (BIA), which passes a small electrical impulse through your body to measure its composition, particularly the ratios of fat and water.
Waist measurement, which can indicate whether you are carrying excess weight.
Waist-to-hip ratio – the results of dividing your waist measurement by your hip measurement can be an indicator of weight issues. The ratio should be no more than 0.9 for men and 0.8 for women.
Seeking medical advice about your optimum weight definition
If you feel you need to lose weight and improve your health, it’s likely that you want to work towards a figure that pinpoints your ideal/optimum weight.
As we’ve seen in this article, this isn’t always as straight forward as we might think.
This is just one of the reasons that we would always advise someone seeking to lose weight to speak to their doctor first.
A doctor can look at all of the factors that influence your weight and help you understand what’s healthy for you, then come up with an achievable goal that you feel comfortable with.
Here at Medikaur, we offer the National Medical Weight Loss Programme because it looks at the bigger picture provided by your body composition, lifestyle, diet, health and many other factors. We believe that this holistic approach delivers better long-term results than using your BMI alone to define your optimum weight.
Find out more about the National Medical Weight Loss Programme at Medikaur here.