Going hungry can make you miserable, and a new study shows that it can make you sick too.

A recent study by UCSF researchers followed low-income HIV patients in San Francisco over two years and tracked their visits to emergency rooms during that time.  Of the 347 participants, all of whom lived in substandard housing, 56 percent of them were classified as “food insecure,” which means they regularly worried about getting access to enough food.

Those who were food insecure ended up at the ER or being hospitalized twice as often as those who had regular access to nutritious meals, according to the study’s primary investigator, Sheri Weiser, MD, an assistant professor of medicine at the UCSF HIV/AIDS Division.

“For a long time we have known that adequate nutrition is crucial for HIV-positive patients to live long healthy lives. Our findings that food insecure individuals are also more likely to use costly services from hospitals and emergency rooms build on our previous work showing that food insecure individuals experience poorer HIV treatment outcomes,” Weiser said.

Food insecurity is a much bigger issue in San Francisco than elsewhere in the country because of the high cost of living in the city. By the time a person pays rent for a single-room occupancy (SRO) unit, many of which don’t include kitchen facilities, there’s little money left to buy food – much less a well-balanced meal.

Nationwide, one in seven Americans is considered food insecure. That figure jumps to one in five in San Francisco, according to the San Francisco Food Bank.

Local organizations such as Project Open Hand and Glide have worked hard to provide food to low-income, HIV-infected people in the city, but they’ve been strained by funding cutbacks.

The study suggests that paying for a basic need like food for these individuals could save thousands or millions in health care costs down the line.