President Trump has made some pretty big league promises when it comes to improving Americans' health care.

Even before he launched his presidential campaign in 2015, Trump regularly blasted Obamacare and promised to replace it with something that costs less. On the trail, he vowed to have the government pay to cover the poor so they don't die in the streets. And after he won, he said he wanted coverage for everyone.

"What my plan is is that I wanna take care of everybody. I'm not gonna leave the lower 20% that can't afford insurance," he told ABC News' David Muir in late January. "We're gonna come up with a new plan that's going to be better health care for more people at a lesser cost."

It's not turning out that way -- at least not under the GOP health care bill that Trump has endorsed.

The legislation, now making its way through the House, has been widely criticized. And it would hit many of the president's supporters particularly hard, though Republican leaders are now looking to make some changes to the bill in order to win more support among lawmakers.

Here are three of Trump's promises and the bill's impact on them:

More people will be covered: Trump told a gathering of conservatives last month that Obamacare "covers very few people," reminding the audience that many people lost the insurance plan they loved because of the health reform law.

He has vowed to do better, promising "insurance for everybody."

The Congressional Budget Office, however, estimates that a total of 24 million fewer people would be insured by 2026 under the Republican plan. Many Americans would lose their coverage, while others would not sign up.

Related: CBO report: 24 million fewer insured by 2026 under GOP health care bill

The Republican bill would likely entice some younger folks and some middle income Americans into the individual market, but overall the share of people left uninsured in every age group would climb, the CBO found. Older and lower-income folks would be hit particularly hard.

Also, Medicaid funding would be slashed, leaving 14 million fewer people covered.

While Trump and GOP leaders are downplaying the CBO's ability to correctly forecast coverage, other health policy and industry experts also worry that the legislation would mean many Americans could lose their insurance. S&P Global predicted up to 10 million fewer people would have coverage, while two major insurance industry groups wrote to lawmakers of their concerns that the bill would leave many people unable to afford coverage.

Under Obamacare, some 20 million people gained coverage. The uninsured rate for Americans under age 65 fell to a historic low of 10.3% for the first nine months of 2016.

Costs will be lower: One of Trump's favorite stats to cite is that Obamacare premiums in Arizona went up 116%. He has repeatedly promised that health insurance will be more affordable under his plan.

The GOP bill would be a better deal for many younger Americans because insurers would be able to charge younger folks less compared to older Americans.

The CBO predicted that by 2026, premiums would be 20% to 25% lower for a 21-year-old than they would be if Obamacare were to remain law. A 40-year-old would pay 8% to 10% less.

But older Americans would see their premiums skyrocket by 20% to 25% under the Republican plan.

Related: If you're older and lower income, prepare to pay more under GOP health bill

Premiums under Obamacare, meanwhile, soared an average of 22% this year for the benchmark silver plan. Some states, like Arizona, saw much larger increases. Many people, particularly those who did not qualify for subsidies, complained that coverage was unaffordable.

Federal subsidies, however, reduced the premiums for more than eight in 10 people who bought policies on the Obamacare exchanges. They paid less than 10% of their income for insurance.

Under the GOP bill, more people would be eligible for federal assistance.

Obamacare's subsidies, which are refundable tax credits, are available only to a single person making less than $47,500 or a couple earning $64,000. The GOP bill would provide refundable tax credits to an individual making as much as $215,000 or a couple earning $290,000.

But the GOP tax credits would be worth only half of the Obamacare subsidies by 2026, the CBO projects. That's because they would be based mainly on an enrollee's age, versus the subsidies, which are based on one's income and cost of coverage.

The Republican bill also does little to address consumers' chief complaint -- steep deductibles. Under Obamacare, deductibles could be as high as $7,150 for a single person and twice that for a family.

"The deductibles are so high that you don't really have insurance," Trump said Monday.

In fact, the legislation could make those high-deductible plans more prevalent. That's because it eliminates a requirement that insurers sell plans with lower cost-sharing -- but higher premiums -- on the exchanges, CBO found.

Also, the GOP plan jettisons an additional set of subsidies that help reduce deductibles and co-pays for enrollees who make less than $30,000 a year. They will wind up paying a lot more to get medical care.

The poor will be able to afford coverage: Trump has repeatedly said that the government should help pay for coverage for the poor, dismissing the fact that this is not a popular view among Republicans.

"We gotta take care of people that can't take care of themselves," he said in a CNN Town Hall last year.

However, the GOP plan that he supports calls for the largest cuts to Medicaid since it launched in 1965. The legislation would eliminate the enhanced funding for Medicaid expansion starting in 2020, an Obamacare provision that extended coverage to 11 million low-income adults. And it would limit federal support for the entire program, which covers more than 70 million people. This is why the CBO projects such large declines in Medicaid enrollment.

Related: Trump administration open to making some Medicaid recipients work

The restructuring of the refundable tax credits will also make it tougher for lower-income people -- particularly older folks and those who live in high-cost areas, such as rural America, to afford policies in the individual market. That's because the GOP tax credit isn't more generous for lower-income folks nor does it adjust for an enrollee's premium like the Obamacare subsidies.

It's not surprising to some experts that Trump is not living up to his promises.

"You can't simultaneously maintain or increase coverage, hold even or reduce out-of-pocket costs and cut federal spending," said Henry Aaron, a senior fellow at the Brookings Institution. "You just can't do it."