There are a few numbers in life most of us would rather not say out loud, and our weight is often one of them. Body Mass Index, or BMI, tends to sit right alongside it, quietly judged and rarely talked about openly.
Yet when you apply for life insurance, critical illness cover or income protection, BMI is one of the first things an insurer looks at, and it can have a real effect on what you pay and whether you are accepted at all.
It is worth understanding, because when it comes to protection, that one number can carry more weight than people realise.
What BMI actually is
BMI is a simple calculation. You take your weight in kilograms and divide it by your height in metres squared. The result places you in a category: underweight, healthy, overweight and varying levels of obesity.
It has been used for decades because it is quick, cheap and easy to apply across a whole population. The NHS uses it, employers use it, and the insurance industry leans on it heavily.
The honest truth is that BMI is a blunt instrument. It cannot tell the difference between fat and muscle, which is why a fit rugby player and someone carrying excess weight can end up with an identical score. It takes no account of where you carry weight, your age, your ethnicity or your overall fitness.
Plenty of healthy people sit outside the so-called ideal range, and plenty inside it are not especially well.
Is a single number really a fair measure of a person? In a medical sense, not entirely. In an insurance sense, though, it remains the starting point, so it pays to understand how it is used.
Why insurers care about it
Insurers price cover based on risk. A higher BMI is associated, at a population level, with a greater likelihood of conditions such as type 2 diabetes, heart disease, high blood pressure and joint problems.
That does not mean any one individual will become unwell. Underwriters are not looking at your whole life story in the same way you are. They work with averages, statistics and probabilities. The higher your BMI climbs, the more an insurer may worry about the chance of a future claim, and that concern can show up in your premium.
For many providers, there is a point where their approach starts to change. In our experience, that point tends to arrive around a BMI of 34. Below it, many applicants are offered standard terms or only a modest increase. At 34 and above, a lot of insurers begin loading premiums more heavily, asking for further medical evidence, or in some cases declining the application.
It is not a universal cut off, and every insurer sets its own rules, but it is a threshold worth knowing about before you start filling in forms.
What this means in practice
Here is where it gets frustrating for people. Two applicants with very similar health can receive completely different decisions simply because they applied to different insurers.
One provider might decline at a BMI of 35 while another offers cover at a slightly higher premium. The criteria sit behind the scenes, and unless you know the market, you are largely applying blind.
This is exactly where a broker earns their keep. Rather than approaching one insurer, hoping for the best and risking a refusal that then sits on your record, we look across the whole market and match you to the providers most likely to offer sensible terms for your circumstances.
We know which insurers take a more flexible view of BMI, which may prefer a nurse screening, and which will weigh other factors such as blood pressure, family history and lifestyle alongside the number on the form.
Our advice on personal life insurance and protection is built around finding the right fit, not just the first fit.
It matters just as much for income protection, where being unable to work through illness or injury can put real strain on a household budget. The products that feel least urgent are often the ones people only realise they need when life changes.
A higher BMI should not have to mean going without cover. With the right advice, you give yourself the best chance of a fair outcome.
A kinder way to think about it
If your BMI is on the higher side, please do not read any of this as a telling off. It is information, not judgement.
The point of talking about the number openly is to take some of its power away. Knowing where you stand, understanding how insurers read it, and getting advice from someone who works with these criteria every day can help put you back in control.
In part two, we will look at the practical side: small, realistic changes that can help bring your weight and your BMI down over time, without crash diets or misery. Because the best outcome is not only better insurance terms. It is feeling better day to day.
