BMI calculator for Milton Keynes

Where BMI is misleading

It measures weight, not what the weight is made of. Someone who trains heavily can read in the overweight range while carrying very little fat, and an older person who has lost muscle can read in the healthy range while carrying rather a lot.

It also reads differently across populations. NICE advises using a lower threshold for people of South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean family background, because the health risks associated with a given BMI arrive earlier. If that applies to you, say so at the assessment.

How to measure yourself accurately

A BMI is only as good as the two numbers that go into it, and most people who work it out at home get one of them wrong. Weight should be taken first thing in the morning, before breakfast, on a hard floor rather than a carpet, bathroom scales read low on a soft surface, sometimes by a couple of kilograms. Weigh yourself in light clothing and use the same scales every time, because the trend matters more than any single reading.

Height is the number people are least accurate about, usually because they are quoting a figure they were last told in their twenties. Adults lose height gradually, and an error of three centimetres moves a BMI by roughly a whole point. Measure with your shoes off, heels against a wall, looking straight ahead, and mark the wall with a flat object resting on the crown of your head rather than a hand.

If the two figures put you close to a threshold, it is worth being measured properly rather than deciding on the basis of a home reading. Height and weight are both taken at the clinic at the start of the assessment, and that measured figure is the one a prescriber works from.

BMI, waist measurement and body shape

BMI describes weight relative to height and nothing else. It does not know where that weight is carried, and where it is carried matters clinically. Fat around the middle sits close to the liver and pancreas and is more strongly associated with type 2 diabetes and heart disease than the same amount of weight carried on the hips and thighs. Two people with an identical BMI can have quite different risk profiles.

That is why a waist measurement is taken alongside BMI. Measure around the middle, roughly halfway between the bottom of the ribs and the top of the hip bones, with the tape flat against the skin and after breathing out normally. As a general guide, a waist of more than half your height is worth discussing whatever your BMI says.

NICE guidance is explicit that BMI should be interpreted alongside waist measurement rather than used on its own, and that thresholds should be applied with more caution in people of South Asian, Chinese, Black African and African-Caribbean family background, where the risks associated with a given BMI tend to appear at a lower number. Milton Keynes is a young and unusually diverse city, and that adjustment is relevant to a great many of the people who ask us about this.

What happens after you know your number

Knowing your BMI tells you which conversation to have, not which treatment to take. Broadly, there are three answers, and only one of them involves a prescription.

Below the threshold

If your BMI is under 27 there is no licensed weight loss medicine indicated for you, and a pharmacy that offers you one anyway is not one to use. What is useful at this point is the ordinary, unglamorous set of things: what you eat, how much you move, how you sleep and how much you drink. Your GP practice can refer into the free local weight management support commissioned across Milton Keynes, and for many people that is the right and sufficient answer.

Between 27 and 30

This is the band where the rest of your health decides it. A licensed weight loss medicine may be appropriate if you also have a weight-related condition, type 2 diabetes, high blood pressure, raised cholesterol, obstructive sleep apnoea, or established heart disease. Whether one of those applies is a clinical judgement made with your records in front of the prescriber, not something to self-assess from a web page.

30 and above

At a BMI of 30 or more, treatment is usually considered on the BMI alone. That does not mean it will be prescribed: the assessment still checks your medical history, the other medicines you take, any history of pancreatitis, thyroid or gallbladder problems, and whether you are pregnant, breastfeeding or planning a pregnancy. Some people who are well above the threshold are still not suitable, and are told so.

How common this is in Milton Keynes

It is worth saying plainly that a BMI over 30 is not unusual. The Health Survey for England found that around three in ten adults in England are living with obesity, and Milton Keynes is not an outlier. Applied to a borough of roughly 290,000 people, that is a substantial share of the adult population, tens of thousands of people, for whom this page is describing something ordinary rather than exceptional.

We mention it because shame is the single most common reason people give for having put off asking. Weight is discussed at this clinic the way blood pressure is: a number, its context, and what can sensibly be done about it. Nobody at Kenmakos Medical is going to be surprised by your reading.

Checking your BMI in Milton Keynes

You can work it out here in ten seconds, and most people do before they call. What a calculator cannot do is weigh you properly, take a blood pressure reading or look at the medicines you are already on, which is what the assessment at the clinic is for.

Kenmakos Medical is on Barton Road in Bletchley, a few minutes from the station and with free parking outside. Appointments run to 8pm on weekdays and on Saturdays, which matters when treatment involves coming back once a month rather than once.