Insurers Ran the Numbers on Obesity and GLP-1s

There is a group of professionals whose whole job is to price how long you will live. They are actuaries, and their tables help set what life and health insurance cost for everyone who buys it. When they look at the United States, one number keeps coming back: the share of adults with obesity. Here is what they see, what it costs, and what the world's largest reinsurers project GLP-1 medications will change.

The people who price your life

An actuary uses data and statistics to price risk. A reinsurer is a company that insures insurance companies. Swiss Re, Munich Re and RGA are among the largest, so their mortality models ripple down into the price of individual policies.

The stakes are large. U.S. life insurers held a record $22.2 trillion of life insurance in force in 2023 and paid $89 billion to beneficiaries that year ¹ACLI Fact Book, 2024Industry reportAnnual statistics on U.S. life insurers, 2023 data. When a model of how long people live shifts, even slightly, it moves a great deal of money.

That is also why your height and weight sit on a life insurance application. Insurers use a build table, a height and weight chart, to help place each applicant in a rate class.

Four in ten adults

The CDC's national health survey measures people instead of asking them, so its numbers are the ones actuaries trust. In the latest round, from August 2021 to August 2023, 40.3 percent of U.S. adults had obesity and 9.4 percent had severe obesity ²CDC NCHS Data Brief 508, 2024Government dataNational survey with measured height and weight (NHANES). That is about four in ten adults, and nearly one in ten.

The climb has been long and steady. Among adults ages 20 to 74, obesity rose from 13.4 percent in 1960 to 1962 to 40.8 percent in 2021 to 2023. Severe obesity rose from 0.9 percent to 10.2 percent over the same span ³Fryar et al., 2026Government dataSixty years of measured national survey data, ages 20 to 74.

The forecasts point higher. A Harvard-led team corrected self-reported weight data from more than 6 million adults and projected that 48.9 percent of U.S. adults will have obesity by 2030, with 24.2 percent at severe obesity ⁴Ward et al., 2019Forecasting studySelf-reported data from 6.26 million adults, corrected with measured data. A 2024 analysis in The Lancet projected that, if past trends continue, 213 million American adults age 25 and older will have overweight or obesity by 2050 ⁵GBD 2021 US Obesity Forecasting Collaborators, 2024Forecasting study134 data sources, forecasts assume past trends continue. That second figure counts overweight as well, so it measures something broader than the first.

The medical bill

The CDC links obesity to about $173 billion a year in U.S. medical costs, in 2019 dollars ⁶CDC, Adult Obesity FactsGovernment dataNational medical cost estimates, 2019 dollars. Per person, an adult with obesity averages about $1,861 more in medical costs each year, and an adult with severe obesity about $3,097 more ⁶CDC, Adult Obesity FactsGovernment dataNational medical cost estimates, 2019 dollars.

Someone pays that bill. In a shared plan it is spread across employers, insurers and everyone else in the pool, which is why a trend in body weight shows up in the price of coverage for people of every size.

What life insurers see

Health insurers see claims. Life insurers see deaths. In its 2025 review of the evidence, the reinsurer RGA cites research linking excess body weight to almost 500,000 excess U.S. deaths in 2016 alone ⁷RGA, 2025Industry reportReinsurer review of GLP-1 evidence and adherence studies.

An award-winning essay from the Society of Actuaries Research Institute describes the difference in time scale. If COVID-19 was "a sudden storm," the author writes, obesity is "the slow-moving tide" ⁸Nanda, Society of Actuaries, 2026Professional essayActuarial essay, the author's own views. A storm spikes and passes. A tide keeps rising.

Actuaries call the yearly change in death rates mortality improvement. A small change each year compounds over decades, in either direction. That is why a trend that moves slowly still worries the people who price it.

The GLP-1 math

When GLP-1 medications arrived, the big reinsurers ran the numbers. Their projections are worth reading closely, because getting mortality right is how they stay in business.

Swiss Re's best case projects U.S. mortality up to 6.4 percent lower by 2045 ⁹Swiss Re, 2025Industry reportReinsurer mortality scenarios to 2045. That case assumes high use, for the long term, with people also changing how they live. Its cautious case is 2.3 percent ⁹Swiss Re, 2025Industry reportReinsurer mortality scenarios to 2045. Both are measured against the death rates Swiss Re expects without the medications.

Munich Re studied a de-identified U.S. dataset covering 41 million lives. It models an improvement of 0.2 to 0.5 percent a year, realized over a 20-year period ¹⁰Munich Re, 2026Industry reportDe-identified U.S. dataset of 41 million lives, 2015 to 2025.

Set those numbers next to an obesity rate of 40 percent. A few percent is real, and over millions of lives it matters. It is not a rescue. The curve bends, slightly.

The catch: staying on it

Every one of these projections depends on people taking the medication for years. The data so far shows many do not.

In Munich Re's dataset, about 60 percent of people with diabetes were still taking a GLP-1 medication after one year. Among people without diabetes, fewer than 4 in 10 were. Among people without diabetes ages 30 to 40, fewer than 3 in 10 were ¹⁰Munich Re, 2026Industry reportDe-identified U.S. dataset of 41 million lives, 2015 to 2025.

RGA points to a separate study in which about two thirds of patients stopped within the first year ⁷RGA, 2025Industry reportReinsurer review of GLP-1 evidence and adherence studies. A model can assume long-term use. Real life has to deliver it.

Where the money matters

Read the assumptions behind the best cases and a pattern shows up. Swiss Re's highest number requires long-term use and lifestyle change together ⁹Swiss Re, 2025Industry reportReinsurer mortality scenarios to 2045. Munich Re's range is held back by how many people stop ¹⁰Munich Re, 2026Industry reportDe-identified U.S. dataset of 41 million lives, 2015 to 2025. The models price the medication, and then they come back to the same thing: what people do every day, for years.

That daily part is meals, movement, sleep, and knowing your own numbers. No actuary can model it for you. It is also the part of the equation that belongs to you, with medication or without it.