BMI Calculator


Here we go, another piece on weight-hasn’t it all been done to death? Well, maybe its time to look at it a different way. I am a firm believer in the importance of putting the right fuels into your body and how this means you will feel better and probably eat less.

There is no question that carrying excess weight is not healthy for a number of reasons. The question is what constitutes overweight? The Body Mass Index (BMI) which is used to estimate body fat has its uses but also problems. It came about from work done in the 1940s by insurance actuaries and work on “normal weight” from the 1830s. The arbitrary cutoffs came from the International Obesity Task Force. All this seems a bit out of date and perhaps of questionable relevance today.

The standard definitions of weight ranges are as follows:


Under 18 – very underweight and possibly malnourished.

18.0-19.9 – underweight and could afford to gain a little weight.

20 to 24.9 – healthy weight range for young and middle-aged adults.

25 to 29.9 – overweight

Over 30 – obese.

What is so special about a BMI of 25 as against 27? Many sports people are classed as overweight because they are muscle bound. Arnold Schwarzenegger was “obese” when he won Mr. Olympia. Many football players would also be technically overweight. The BMI also does not include a differentiator for men and women.

A recent study has followed over 11,000 people for 12 years and found those who were technically overweight (BMI 25-29.9) had lower death rates than those with a “normal” BMI (18.5-24.9). Now I am always suspicious of studies but whenever there is one, which challenges conventional wisdom, I am more interested. Whilst research is presented as “scientific, “ to publish findings, which are against the herd, mentality is difficult.

A more useful indicator of health risk is the waist circumference. A “pot belly” at any size can predispose you to diabetes, high blood pressure and heart disease. Fat deposited on the hips and buttocks doesn’t seem to have the same risks. Here is a broad guide.

Least risk – slim (no pot belly)

Moderate risk – overweight with no pot belly

Moderate to high risk – slim with pot belly

High risk – overweight with potbelly.

Waist circumference and health risks

Waist circumference can be used to indicate health risk.

For men:

94cm or more – increased risk

102cm or more – substantially increased risk.


For women:

80cm or more – increased risk

88cm or more – substantially increased risk

The central question in all this is remains what constitutes overweight and obesity. We can probably all spot it when we see it but can we define it? More importantly can one measure be applied to all people in all circumstances – the answer to that one is no.

Like most things with the body there is a “right” level above and below which there are health issues. With weight there is a level, which will impact on your health. That level may not be a BMI of 25. The likelihood is that the “correct “ BMI for most people is somewhere between 20 and 30. There are much better markers for health issues than the BMI.

Focus on eating food that until recently was moving around or growing somewhere, food that your ancestors from 100 years ago would recognize as food, food that if not eaten would have to be thrown out next week. Following these simple guidelines will make it far more likely that your weight will be in the zone that is right for you.