A new study released Tuesday shows just how insidious the Trump administration’s proposal to change the way the federal government measures poverty actually is. In short: millions could lose health and food benefits.

By way of background, in May, Trump’s budget agency sought public comment on updating the inflation rate used by the Census Bureau to determine the poverty line and estimate who’s poor. This technical change matters a lot because the federal poverty line is used to determine who’s eligible for government benefits like Medicaid, food stamps, and other assistance programs.

The administration floated a lot of options to replace what’s known as the Consumer Price Index (CPI), which is what the government currently uses to estimate the federal poverty line. But given the administration’s desire to slash benefits, as made clear over the years in proposed budgets and bills, it is likely to use a measurement that would redefine poverty in a way that cuts federal assistance to millions of low-income Americans.

The Center for Budget and Policy Priorities (CBPP) analyzed the effects of one option the administration is likely leaning towards: “chained CPI” (or C-CPI), which was also used in the GOP tax bill passed in 2017. Chained CPI usually grows slower than traditional CPI, which means a lot of low-income people would be at risk of losing aid if the administration moves forward with this option.

The CBPP estimated that by the 10th year of calculating the poverty line using chained CPI, millions of people — including pregnant women and children — would become ineligible for or receive less help from various government programs.

Here’s the progressive think tank’s breakdown:

• More than 250,000 adults would lose health insurance through Medicaid.
• More than 300,000 kids and some pregnant women would lose health insurance through the Children’s Health Insurance Program (CHIP).
• Millions of people would receive fewer subsidies for purchasing health insurance on the Obamacare marketplace, making it more expensive to do so.
• More than 250,000 seniors and people with disabilities would lose or receive less access to the Medicare Part D subsidy program, forcing them to pay more for prescription drugs.
• More than 150,000 seniors and people with disabilities would lose premium assistance for Medicare Part B, meaning they’d have to pay over $1,500 to see a doctor.
• Nearly 200,000 people would lose food benefits through the Supplemental Nutrition Assistance Program (SNAP).
• More than 100,000 students would become ineligible for free or reduced-price lunch, and more than 100,000 would lose free meals but remain eligible for reduced-price lunch.
• About 40,000 infants and young children would lose access to care such as breastfeeding support and healthy food through the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).

Due to some limitations, CBPP says it likely “modestly” overstated the impact of eligibility changes, but that “should not change the qualitative conclusions.” The bottom line is people will lose government assistance. It will be acute for those who do, with some losing multiple benefits.

In a press call on Tuesday, CBPP Vice President for Health Policy Aviva Aron-Dine noted this is one of the “most sweeping” federal actions affecting poor and modest Americans. The administration would also be undermining some of its own policy priorities, including addressing the rising cost of prescription drugs.

The ultimate irony, said Aron-Dine, is that by making the hardship worse, it makes it seem like fewer people are poor. But in reality, there’s strong evidence to suggest that the current poverty line underestimates what poor families need and that these families experience higher inflation than the general population as a whole, she said.

The public comment period for this rule will end on Friday, at which point the administration can move forward with its guidance. There are legal questions as the guidance is not moving forward through formal rule making.