In the US, where medical underwriting of private health insurance plans is widespread, most private health insurance providers will use a particular high BMI as a cut-off point in order to raise insurance rates for or deny insurance to higher-risk patients, thereby reducing the cost of insurance coverage to all other subscribers in a 'normal' BMI range. The cutoff point is determined differently for every health insurance provider and different providers will have vastly different ranges of acceptability.
Many will implement
phased surcharges, in which the subscriber will pay an additional
penalty, usually as a percentage of the monthly premium, based on
membership in an actuarially determined risk tier corresponding to a
given range of BMI points above a certain acceptable limit, up to a
maximum BMI past which the individual will simply be denied
admissibility regardless of price. This can be contrasted with group insurance policies
which do not require medical underwriting and where insurance
admissibility is guaranteed by virtue of being a member of the insured
group, regardless of BMI or other risk factors that would likely render
the individual inadmissible to an individual health plan.