Am I overweight? How to check, and when to see someone

The quickest check is your BMI, and the better one adds your waist. The NHS treats a BMI of 25 to 29.9 as overweight and 30 or more as obese for most adults. For people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean backgrounds the thresholds are lower: 23 to 27.4 is overweight and 27.5 or more is obese.

Then measure your waist. NICE advises keeping it to less than half your height, and the NHS waist-to-height calculator does the arithmetic. The NHS adult BMI calculator does the same for BMI.

• Whether the weight is muscle or fat: the NHS says the BMI calculator cannot tell the difference
• Where the weight sits, which a waist measurement shows and BMI does not
• That cardiometabolic risk starts at a lower BMI for some ethnic backgrounds, which NICE builds into its thresholds
• Whether anything treatable, such as an underactive thyroid, is driving a recent change
• Whether weight loss is the right goal for you at all

NICE classes a BMI of 18.5 to 24.9 as a healthy weight for adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and obesity runs in classes from 30 upwards. For people whose family background is South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean, NICE uses lower thresholds because health risk starts at a lower BMI: overweight from 23 and obesity from 27.5.

BMI is a screening number rather than a verdict. It was built for populations, and it says nothing about where weight is carried or how much of it is muscle.

Divide your waist by your height. NICE treats 0.4 to 0.49 as healthy, 0.5 to 0.59 as increased central adiposity with increased health risks, and 0.6 or more as high. It recommends measuring waist-to-height ratio as well as BMI for adults with a BMI under 35, because fat carried around the middle says more about health risk than weight alone.

It is also the number most likely to move when the scales do not. A month where your weight holds still and your waist comes down is progress, and it is a reason to track both.

For a population it is useful; for one person it can mislead. The NHS says the BMI calculator cannot tell the difference between muscle and fat, so a muscular person can read as overweight, and someone with little muscle can read as healthy while carrying weight around the middle. That is why a first assessment arranged through Weight Loss Clinics Mayfair takes a waist measurement and blood pressure alongside height and weight, and looks at bloods before drawing a conclusion.

The NHS suggests seeing a GP if your BMI is in the overweight or obese range and you would like help losing weight, if your waist is more than half your height, or if you have a health condition linked to weight, such as type 2 diabetes or high blood pressure. Your GP can also refer you to NHS weight management services, which are free.

See a GP promptly, rather than waiting for any assessment, if your weight has changed quickly without an obvious reason.

If your BMI is already in the healthy range, or under 18.5, further weight loss carries risk and no health benefit. If eating has become a set of rules that is hard to break, if a missed plan brings guilt out of proportion to it, or if losing weight has stopped feeling like a choice, talk to somebody before anyone builds a plan.

Beat, the UK eating disorder charity, runs a free England helpline on 0808 801 0677, 15:00 to 20:00 on weekdays, with online support at beateatingdisorders.org.uk. Your GP can refer you to NHS eating disorder services. Both come before a weight management clinic.

If the numbers suggest you are carrying more weight than is healthy, a first private weight management assessment takes 45 to 60 minutes: your weight history, height, weight, waist, blood pressure and bloods, ending in a written plan and a review date. UNTIL Health Concierge arranges it with a registered practitioner at UNTIL Marylebone, 1 Orchard Street, 7 minutes on foot from Bond Street station, once you send the enquiry form.