Diet and weight: a grocery store on wheels cut salt in housing communities

If you care about diet and weight, you have probably wondered whether bringing healthy food closer to home changes what people eat. A new trial gives a useful, mixed answer. In a study of 242 adults living in subsidized housing in the Minneapolis-St. Paul area, people at sites with a weekly grocery store on wheels ate about 400 mg less sodium a day than people at sites still waiting for it.

The truck did not move the needle on overall diet quality or on most other eating measures. Still, less salt is a real result, and almost everyone who used the market said they would recommend it.

How the study worked

Researchers tested the Twin Cities Mobile Market, a full-service grocery store in a truck that sells low-cost, nutritious food. They worked with 12 public or private subsidized housing sites, and the sites were randomly assigned to get weekly market visits or to wait their turn. About 9 in 10 of the 242 adults stayed in the study through follow-up. Results were published on November 2, 2026, in JAMA Network Open. Not everyone shopped at the truck, since 43.1% of people at market sites used it at least once in months 5 and 6, so the results reflect real-world use rather than a perfect dose.

People reported what they ate through detailed 24-hour food recalls, where a trained interviewer asks what you ate and drank over the past day. Follow-up checks began after 6 months of market service.

What they found

The clearest result was about salt. People at the market sites ate 397 mg less sodium each day than people at the waiting-list sites. That is roughly 400 mg, which is a meaningful drop in a daily diet. The researchers noted that a change like this could improve health across a whole community.

Overall diet quality, the main thing the study measured, was not meaningfully different between the groups. The score is built from many parts of eating, such as fruits, vegetables and grains. The gap was only 1.25 points, and the study could not tell it apart from no difference.

Most of the other measures also showed no clear difference between the groups:

• Fruit and vegetable intake
• Total calories
• Added sugar intake
• Food security, meaning how reliably people had enough food
• Fruit and vegetable servings brought into the home

One extra check is worth knowing about. When researchers looked only at people who followed the plan closely, those in the market group got 2.35% more of their calories from added sugar than the comparison group. That did not show up in the main analysis.

The good news on the experience side is strong. Of 94 people who said they had ever used the market, 90 (95.7%) would recommend it. Each site averaged about 18 weekly transactions.

Why does less sodium matter?

Sodium is the part of salt that most affects how your body holds water and how hard your heart works. Much of it comes from packaged and prepared foods, not the salt shaker. When a store brings fresher, simpler options to your door, it can nudge what ends up in your cart. The study did not pin down exactly which foods drove the drop, so treat the cause as an open question.

What you can do today

Pick one packaged food you buy often, like canned soup, bread or frozen meals. Next time you shop, compare the sodium line on the Nutrition Facts label (the FDA has a simple guide) across two brands. Put the lower-sodium one in your cart.

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