Inside the vast interior of a trailer, stark portraits line the walls — haunting black-and-white portraits of people touched by hunger in the United States.

This big rig isn’t just a truck. It’s a traveling, interactive exhibit put on by Mazon, a Jewish advocacy and policy group working to end hunger in this country and Israel.

The photographs are by Barbara Grover, and the exhibit on wheels is called “This Is Hunger.” Its aim is to introduce people to stories that show just how deep and pervasive the problem is.

Inside the 53-foot-long double expandable trailer, visitors will hear first-person accounts from people like John, a boy in Michigan who wishes he could get a job to help his family, or Whitney, who at 65 can’t afford to buy vegetables.

Since the project is sponsored by Mazon: A Jewish Response to Hunger, the truck’s 16-month tour has stopped at synagogues and Jewish institutions from Phoenix to Nashua, New Hampshire, and from Seattle to Miami — more than 50 cities in all since kicking off in Los Angeles in November 2016.

As it heads into the homestretch, the truck is visiting four spots in the Bay Area this month: Congregation Beth David in Saratoga (Jan. 7-10), the Peninsula JCC in Foster City (Jan. 11-14), the Brandeis School of San Francisco (Jan. 16-20) and Congregation Beth Am in Los Altos Hills (Jan. 23-26). The truck will be parked on-site at each institution, except for Brandeis, where it will be just down the road at 855 Brotherhood Way outside a Mason’s lodge.

Visitors may sign up for a 45-minute visit, and groups of 30 will be admitted at assigned times during the day. Admission is free, but tickets need to be reserved in advance.

The experience is interactive. For example, as visitors sit around a communal table, they will see projected portraits and hear recordings of people telling their stories in their own voices.

According to Mazon, some 42.2 million people, including 13.1 million children and 5.7 million seniors, struggle with hunger, but the problem is largely unseen, hidden by stigma and ignorance. Many who have taken the tour have been surprised to find out the level of food insecurity among seniors; for example, three out of five seniors who are eligible for food stamps opt not to participate in SNAP (Supplemental Nutrition Assistance Program), “because they think there’s a stigma attached to receiving those benefits,” said a Mazon organizer.

The truck was at Congregation B’nai Israel in Sacramento over the summer and will be wrapping up its long tour in Southern California from Jan. 28 through Feb. 14.