And that's just the beginningWhy your health insurance company calculates your BMI
Stefan Michel
10.11.2025
Your weight is a private matter? Not for your health insurance company if you want supplementary insurance.
Annette Riedl/Deutsche Presse-Agentur GmbH/dpa
The body mass index is part of the health data that health insurance companies record when new customers register. This information plays an important role for supplementary insurance.
10.11.2025, 12:21
10.11.2025, 21:21
Stefan Michel
No time? blue News summarizes for you
The body mass index (BMI) may not play a role in compulsory basic insurance, but is a permissible factor for supplementary insurance when deciding on admission and benefit restrictions.
In addition to the BMI, insurers also use other health data such as previous illnesses or lifestyle to define risk groups and collectively calculate higher premiums.
Why it is not advisable to lie to your insurer.
Health expert Felix Schneuwly expects genetic factors to play an increasingly important role in calculating premiums in the future - to the detriment of people with inherited health risks.
"How tall are you and what is your weight?" the health insurance employee suddenly wants to know. "And your wife?", the data recording continues. "I'll quickly work out your BMI," says the man at the other end of the line. "Okay, that fits," he says when a value of 25 comes out - the borderline between normal and overweight.
blue News reader M. M. is surprised, but doesn't want to jeopardize the conclusion of a health insurance policy that seems relatively advantageous. The fact that certain health data is recorded is part of the standard repertoire when changing health insurer.
But what role does it play if someone is slim or overweight? Felix Schneuwly, health expert at the comparison portal Comparis, puts it clearly: "If it's only about basic insurance, nothing at all. It would be illegal to include the BMI in the basic insurance premium."
The Health Insurance Act also stipulates that insurance companies must accept everyone living in Switzerland, regardless of their physical condition.
The situation is different for supplementary insurance. Schneuwly explains: "Freedom of contract applies here. Insurers can set the conditions under which they insure people themselves."
This also includes the criteria they use to calculate the premiums for supplementary insurance: "All costs of the insured medical services or indicators that correlate with the service costs are relevant for calculating the premiums."
A high body mass index, which is synonymous with being overweight, can indicate that a person will make use of more healthcare services - in other words, it could cost the insurance company money. Schneuwly also cites this statistical correlation. Another such disease risk is smoking.
What the health insurance companies said
blue News asked the largest Swiss health insurers what role the body mass index plays in their supplementary insurance policies.
Eight out of twelve responded. All of them deny that this parameter influences the amount of the premium. On the other hand, they reserve the right not to accept people or to exclude certain benefits if their BMI is not within the desired range.
According to health expert Schneuwly, fibbing to the insurance company in order to obtain more favorable conditions is not a good idea. If it later transpires that the insurance contract was concluded on the basis of false information, the insurer could refuse to cover the costs, make exclusions from cover retrospectively or cancel the contract.
What other data insurers are interested in
It should be noted that in addition to the BMI, there are various other health-related private data that health insurance companies record and which can play a role, such as previous illnesses, current illnesses, congenital defects, chronic illnesses, drinking and smoking habits.
On this basis, insurers calculate how high the risk of a group of people is of developing certain illnesses and needing treatment.
The more accurate the picture they have of each of their policyholders, the more accurate their forecast of expected costs - not for each individual person, but for a large group with similar information.
Indirectly, together with the other health data collected, the BMI does therefore have an influence on the amount of the premium - not individually for the individual person, but for the group of insured persons with a similar risk profile.
According to the principle of solidarity, everyone who falls into the same category due to their physical condition pays the same amount.
Paying more because of "bad genes"?
Felix Schneuwly expects genetic factors to play a greater role in the future, as they enable increasingly accurate predictions to be made about how high the healthcare costs to be covered will be for a group of insured persons.
The consequence: "Either the premiums for certain risk groups will then become very high or the insurers will change the system." According to Schneuwly, the problem for health insurance companies is that they cannot exclude more and more people from their offers, because then they would eventually no longer have enough customers.
Instead, they could reward their policyholders for helping to keep costs down by leading a healthy lifestyle. "The question is how insurers measure this and whether the parameters they measure are really the ones that significantly influence a person's health."
Contributions to fitness subscriptions or the inclusion of data from sports watches are still just marketing measures. "Insurers need to develop these systems with medical experts," Schneuwly demands.
Passing a genetic test can be required
Genetic tests are not yet required to take out supplementary insurance. "However, when taking out supplementary insurance, you may be asked whether you have had a genetic test. If so, the insurance company can ask you to submit it," explains Schneuwly.
Anyone who conceals an existing genetic test in such a case so as not to have to share it with the insurance company is deceiving the company, which could have an impact on subsequent insurance benefits.
It is still a dream of the future, but according to Felix Schneuwly, it is quite realistic that people in Switzerland will one day be asked to pay even more for congenital health factors than they have to date.
Perhaps people who are unlucky with their genetic make-up could fight this with exercise, a healthy diet and enough sleep and get a premium bonus. However, they would still pay more than their fellow policyholders with a favorable genetic make-up who also lead a healthy lifestyle.