A research study conducted by Harvard University revealed that since rental prices have been going up while ownership has gone down, 40 million U.S. citizens are forced to pay “more than they reasonably should” for houses they can’t afford. The researchers have determined the affordability by comparing the prices to Americans’ ability to pay not more than 30% of their monthly income on housing; including mortgage, insurance and taxes.

The housing crisis isn’t just taking its toll on Americans who can’t afford rent – it’s a global crisis. According to UN Habitat‘s 2016 report, in 2010, up to 980 million urban households lacked decent housing, and another 600 million are projected to lack decent housing in the coming 13 years. In order for the world to reach 2025 with appropriate housing for everyone, the world needs one billion new homes, which are projected to cost an estimated $650 billion per year, or a staggering total of US$9-11 trillion.

The researchers found that the number of modestly priced units for sale that were put up for less than $800 declined by 261,000 units between 2005 and 2015. Meanwhile, the number of rentals for $2,000 or more increased to 1.5 million units. That reflected on having nearly 19 million Americans pay more than 50% of their income to cover their housing needs.

“Over 38 million American households can’t afford their housing, an increase of 146% in the past 16 years,” the study reads, adding that the more fortunate ones haven’t dodged the ramifications. “The typical homeowner has yet to fully regain the housing wealth lost during the downturn.”

The study finds that ramifications multiply with people with children and families, since they end up paying more than half their incomes to cover housing. “To make ends meet, these families often do not buy enough food for their households or they substitute cheaper but less nutritious foods, either of which can jeopardize their children’s health and development,” the study reads.

In order to balance their expenses, people cut back the most on food. They spend less than $300 a month on food, in comparison to the cost-burden-free average monthly rate of $500.

Home values have gone up by as much as 40% in parts of California, Florida and New England since 2000 and doubled in 12 metropolitan areas. However, they have remained the same or declined by as much as 46% in much of the South and the Midwest. Miami tops the list of high rents, at nearly 62%, followed by Los Angeles and Deltona-Daytona Beach, Florida at 57%. Experts say that all that is needed to get the problem solved is some fixes in the public policies related to housing and engagement of the private sector to help make the region more affordable. They have identified some steps to address the ordeal: Build more homes around public transportation, while encouraging mixed-income developments that include both market-rate and subsidized units. Introducing less restrictive zoning policies that allow for the construction of micro-units and fewer parking spaces would also help alleviate the housing crisis, as well as streamlining the time- and money-consuming permissions’ process for developers.

“There is no city or region that has figured this problem out,” argues Stockton Williams, the executive director of the Washington-based Urban Land Institute Terwilliger Center for Housing. “It’s playing out in Washington, D.C., Boston, Austin, Seattle, San Francisco, Denver, Los Angeles, New York … Any of the 25 most prosperous cities in the United States are all experiencing this growing shortfall of homes for sales and apartments for the middle class.”