Research reviewed by Gram found that a full-service mobile grocery market did not meaningfully improve overall diet quality in low-income housing, but it was linked to about 397 mg less daily sodium. In this 2026 randomized trial of 242 adults, 95.7% of market users said they would recommend it.
A new study looked at whether a grocery store on wheels could help people in low-income housing eat better. Researchers in the Minneapolis-St. Paul area gave weekly mobile market visits to some housing sites and compared them with sites that had to wait. Overall diet quality did not improve in a meaningful way, and most other measures, including fruit and vegetable intake and food security, looked about the same between groups. However, people who had access to the market ate about 397 mg less sodium each day. Nearly all people who used the market said they would recommend it. According to research reviewed by Gram, the market may be a useful tool for reducing salt intake, but it did not fix the bigger picture of diet quality on its own.
Key Statistics
A 2026 randomized clinical trial of 242 adults in subsidized housing found that access to a full-service mobile market was associated with about 397 mg less sodium eaten per day compared with a waiting list control group.
In a 2026 randomized clinical trial of mobile grocery markets, 90 of 94 people who had used the market (95.7%) said they would recommend it to others.
A 2026 randomized clinical trial across 12 housing sites found that overall diet quality did not significantly improve with a mobile market, with an adjusted mean difference of 1.25 points on the Healthy Eating Index.
The Quick Take
- What they studied: Researchers wanted to know whether a full-service mobile grocery market, a store that drives to housing sites and sells fresh and affordable food, could improve what people eat and their access to healthy food.
- Who participated: There were 242 adults who completed the starting assessments, with an average age of about 66 years. About 64% were women, and about 57% received SNAP (food assistance) benefits. All lived in subsidized housing across 12 sites.
- Key finding: Overall diet quality did not change significantly between the groups. People with access to the market ate about 397 mg less sodium per day than the control group, a small but meaningful drop. Most other measures showed no clear difference.
- What it means for you: If a mobile market comes to your building, using it may help lower your salt intake. It is not yet clear that it will transform your overall diet, so pairing it with other healthy habits is still important.
The Research Details
This was a randomized clinical trial, which means housing sites were assigned by chance to either receive weekly visits from the mobile market or to wait and receive it later. Because the sites were randomly assigned, the two groups were expected to be similar at the start, so any differences afterward are more likely to come from the market itself.
The study ran in three waves from January 2022 to October 2025 across 12 public or private subsidized housing sites in the Minneapolis-St. Paul area. Researchers first invited people who said they were interested in the market, then measured their eating habits with 24-hour recalls, where participants described everything they ate and drank in the previous day. Follow-up checks began after six months of market service.
The team looked at a main measure of diet quality, called the Healthy Eating Index, along with intake of fruits, vegetables, calories, sodium, and added sugar. They also measured food security, which is how reliably a household can get enough food, and how much fruit and vegetable produce people bought for home use.
Randomizing sites rather than comparing people who chose to use the market helps reduce the chance that the results were driven by who was already motivated or healthier. Since this approach is considered the strongest way to test whether a program causes a change, it gives the findings more weight than a simple observational study would.
Using 24-hour recalls and a standard diet scoring system also allowed the team to compare results with other national nutrition research. Measuring several outcomes at once, not just diet quality, helped show which changes did and did not happen.
The study used a rigorous design, with random assignment of sites, pre-planned outcomes, and high participant retention. About 90% of enrolled participants stayed in the study through follow-up, which is strong for a trial like this and lowers the risk that dropouts distorted the results.
Several checks were run to test whether the main findings held up. Most results stayed consistent across these checks, though one per-protocol analysis, which looked only at people who actually shopped at the market, found a small increase in calories from added sugar. This type of extra finding should be watched in future studies. Readers should also know that many outcomes were measured, so some results could occur by chance, and that diet data relied on people’s memory of what they ate.
What the Results Show
The main goal was to see whether the mobile market improved diet quality as measured by the Healthy Eating Index. After adjusting for other factors, the difference between the market group and the waiting list group was small, with an average difference of 1.25 points. The range of possible results was wide enough that a true benefit or no benefit could both fit the data, so the researchers could not confirm a meaningful improvement in overall diet quality.
The clearest positive result was sodium. Participants who had access to the market ate about 397 mg less sodium per day than those in the waiting list group. That amount is roughly one-sixth of the daily limit many health groups recommend, so even a modest drop can matter across a whole community.
Most other outcomes showed no significant difference. Fruit and vegetable intake, total calories, added sugar, food security, and fruit and vegetable purchasing for home use did not clearly change in the market group compared with the control group. Participation was also limited: about 43% of people at market sites shopped at least once during months 5 and 6 of the program, so many people in the intervention group did not use it regularly.
Satisfaction was very high among people who used the market. About 96% of those who had ever shopped there said they would recommend it to others, which suggests the service was well received and welcomed by residents. Sites averaged about 18 weekly transactions, and roughly 10% of households made a purchase in a given week, showing steady but modest use.
The per-protocol analysis, which compared only people who actually followed the program, found that participants in the market group consumed about 2.35% more of their calories from added sugar than the control group. This was not seen in the main analysis, so it should be treated as a signal to watch rather than a firm conclusion. It also highlights that how much people actually use a program can shape what the results look like.
Earlier research on mobile markets and similar programs has often reported that they increase access to fresh food and make shoppers happier, and this study confirms those patterns. However, previous studies frequently relied on less rigorous comparisons, so this randomized design adds an important check on whether the benefits are real.
The mixed results here are consistent with broader research showing that improving food access alone does not always change overall diet quality. Factors like cost, cooking skills, food preferences, and how often people shop all seem to matter. The sodium finding fits with research suggesting that changes in the food environment can influence intake of nutrients people often need to limit.
The study was conducted in one metropolitan area with a specific group of older adults living in subsidized housing, so the results may not apply to every community or age group. Participation in the market was far from universal, which likely made it harder to see large changes in diet.
Diet information came from 24-hour recalls, which depend on memory and can be imprecise. The study also measured many outcomes, so some results may have occurred by chance. Follow-up covered a limited time period, and it is not known whether the sodium benefit or other changes would last for years. Finally, the per-protocol sugar result was unexpected and needs further study before it can be understood.
The Bottom Line
Research reviewed by Gram suggests that mobile markets are a promising way to improve access to food and may modestly reduce sodium intake, with moderate confidence in the sodium result. There is less confidence that they will improve overall diet quality on their own, since this trial did not find a significant change. Communities can use mobile markets as one part of a broader plan that also includes nutrition education, affordable pricing, and cooking support.
People living in subsidized or low-income housing, community organizers, housing managers, public health staff, and policymakers planning food access programs should pay attention to these findings. Older adults who have trouble traveling to grocery stores may also find this research useful. People who already eat a varied diet with plenty of produce may not see the same benefits, and anyone with a medical condition that requires specific dietary guidance should talk with a healthcare provider before making major changes.
In this study, changes in sodium intake were measured after about six months of market service. People who shop regularly may notice a difference in their salt intake over several months, but overall diet quality changes typically take longer and depend on many other habits. Longer-term benefits are still unknown and would need more research to confirm.
Frequently Asked Questions
Do mobile grocery markets help people eat healthier?
A 2026 randomized trial found mobile markets did not significantly improve overall diet quality in low-income housing communities. However, participants ate about 397 mg less sodium daily, and most users were highly satisfied with the service.
How much salt can a mobile grocery market help reduce?
In a randomized trial of 242 adults in subsidized housing, people with access to a mobile market consumed about 397 mg less sodium per day than a control group. Results were measured after roughly six months of market service.
Why didn’t a mobile market improve fruit and vegetable intake in the study?
The trial found no significant change in fruit and vegetable intake between groups. Only about 43% of market-site participants shopped there in months 5 and 6, so limited regular use likely made large dietary changes harder to detect.
What is a mobile market and who can use one?
A mobile market is a grocery store on wheels that brings affordable, fresh food to communities with limited access. In this study, it served subsidized housing sites in the Minneapolis-St. Paul area, and it is designed mainly for people with low incomes and limited food access.
Want to Apply This Research?
- Log your daily sodium intake using a food tracker, and compare your weekly average before and after you start shopping at a mobile market. Also track how many servings of fruits and vegetables you eat each day, aiming to see a gradual increase over four to six weeks.
- Plan one mobile market visit per week and choose at least two fresh produce items to add to your meals. Read labels on canned, packaged, and frozen foods to compare sodium levels, and pick lower-sodium options when possible.
- Review your sodium and produce logs once a month for six months, then once a quarter after that. Note any changes in grocery spending, food security, or how often you use the market, and share the trends with a healthcare provider or community nutrition program if you have one.
This article summarizes a single randomized clinical trial and is for general information only. It is not medical or nutritional advice. Results were based on a specific group of adults in one metropolitan area and may not apply to everyone. Before making changes to your diet, especially if you have high blood pressure, kidney disease, diabetes, or other health conditions, talk with your doctor or a registered dietitian.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.